Ib Biology Hl Sem 1

Front 1

What are the characteristics common to all forms of life?

Back 1

reproduction, carbon, responds to surroundings, Growth and Development, cellular organization, and energy

Front 2

What are the levels of biological organization from simple to most complex?

Back 2

Molecules, cell, tissue, organ, organism, population, community, ecosystem, biosphere

Front 3

What are the 4 most common types of biological molecules?

Back 3

Proteins, nucleic acids, carbohydrates, and lipids

Front 4

What is the definition of an organelle?

Back 4

any of a number of organized or specialized structures in a living cell

Front 5

What is the definition of a cell?

Back 5

The smallest structure and functional unit of an organism.

Front 6

What is the definition of tissue?

Back 6

The material of specialized cells and their products that make a wall of cells and their products

Front 7

What is the definition of organ?

Back 7

a part of an organism that is self-contained and serves a function

Front 8

What is the definition of organism?

Back 8

an individual animal, plant, or single-celled life form

Front 9

What are the similarities and differences of a population and an ecosystem?

Back 9

a population and ecosystem both include organisms, however a population is one type of species while an ecosystem is both biotic and abiotic things.

Front 10

What is the definition of emergent properties?

Back 10

the feature that can't be directly from the features of its simpler parts eg. the taste of salt w/ the combination of Na+Cl

Front 11

What are the 4 shared characteristics of cells?

Back 11

DNA, cytoplasm, ribosome, and plasma membranes

Front 12

What is the definition of unicellular organisms?

Back 12

an organism that consists only of 1 cell eg. bacteria/microorganisms

Front 13

What is the definition of multicellular organisms?

Back 13

an organism that consists of multiple cells eg. human

Front 14

What are the similarities and differences between prokaryotic and eukaryotic cells?

Back 14

Prokaryotic cells have no nuclei, unlike Eukaryotic cells. Both are enclosed by membranes and have DNA. Prokaryotic cells have no independent organelles, except for the organelle of ribosome

Front 15

How do the cells in multicellular organisms become specialized?

Back 15

By controlling what DNA is expressed in one cell, because all of the cells in an organism have the same DNA, but only express some. This might include how tight the bindings of the protein are, and if protein is made what the microRNAs do

Front 16

What is sexual reproduction?

Back 16

the production of a new living organism by combining genetics of 2 different sexes

Front 17

What is asexual reproduction?

Back 17

the reproduction of offspring without the fusion of gametes.

Front 18

How do Growth and Development differ?

Back 18

Growth is the process of Development, which is getting bigger/stronger/smarter

Front 19

In the ecosystem, sun's role is to provide what?

Back 19

light

Front 20

When consumers die, what gets nutrients and energy from the dead?

Back 20

The saprotrophs and detritivores

Front 21

What is the definition of homeostasis and an example?

Back 21

The ability or tendency of an organism or cell to maintain internal equilibrium by adjusting its physical processes. eg. body temperature in mammals

Front 22

What is the definition of metabolism?

Back 22

The chemical processes in living organisms in order to maintain life. eg. the mammal's body metabolism can change the need and absorption of energy, depending on environment

Front 23

How does "response to environment" differ from "adaptation to environment?"

Back 23

Response involves the behavior that results from the environment, while adaptation is how structures or functions of an organism change in order to better survive in the environment.

Front 24

What is the definition of adapt?

Back 24

to adjust to the environment

Front 25

What is the definition of anabolism?

Back 25

constructive metabolism that synthesizes more complex substances from simple substances

Front 26

What is the definition of an atom?

Back 26

The smallest unit of matter

Front 27

What is the definition of autotroph?

Back 27

any organism capable of self nourishment to get energy

Front 28

What is the definition of Biome?

Back 28

a large naturally occuring community of fauna and flora occupying that habitat

Front 29

What is the definition of biosphere?

Back 29

it is the part of the earth's crust, waters, and atmosphere that support life

Front 30

What is the definition of catabolism?

Back 30

the metabolism breaking down complex into simple substances with the release of energy

Front 31

What is the definition of cell?

Back 31

the smallest functioning structure of living matter

Front 32

What is the definition of cell membrane?

Back 32

The semipermeable membrane enclosing the cytoplasm of a cell

Front 33

What is the definition of community?

Back 33

a set of species found in the same place at the same time

Front 34

What is the definition of cytoplasm?

Back 34

The cell substance between cell membrane and nucleus

Front 35

What is the definition of detritivore?

Back 35

an organism that uses organic waste as a food source

Front 36

What is the definition of differentiation?

Back 36

process by which cells or tissues change/specialize in development

Front 37

What is an electron?

Back 37

an elementary particle having negative charge and exists outside of the nucleus (electron cloud)

Front 38

What is evolution?

Back 38

process how different living organisms developed and diversified

Front 39

What is growth?

Back 39

Increasing in amount or complexity

Front 40

What is a heterotroph?

Back 40

organism deriving nutrients from complex organic substances

Front 41

What is a molecule?

Back 41

a group of atoms bonded together

Front 42

What is a neutron?

Back 42

a neutrally charged ion inside the nucleus with proton

Front 43

What is organization?

Back 43

organic structure or compositions

Front 44

What is a proton?

Back 44

A positive ion in the nucleus with a neutron

Front 45

What are ribosomes?

Back 45

tiny mitten-shaped organelles that manufacture proteins

Front 46

What is a saprotroph?

Back 46

organism that live and feeds on dead organic matter

Front 47

What is tissue?

Back 47

An aggregate of similar cells and cell products

Front 48

How is the surface area of a cube calculated?

Back 48

6(L)^3

Front 49

How is the volume of a cube calculated?

Back 49

(L)^3

Front 50

How is the surface area to volume ratio calculated?

Back 50

SA:V = 6(L)^2/L^3 = 6/L

Front 51

What happens to the SA:V ratio when the size of the cell increases?

Back 51

the ratio is becoming smaller ad smaller, giving a cell less surface area for the transport of nutrients for given unit volume

Front 52

What does the amount of surface area for a cell dictate?

Back 52

the larger the SA is, the rate of diffusion halves each time cell doubles size, and the cell has a limit before it is too large to metabolize

Front 53

What does the amount of volume dictate in a cell?

Back 53

the number of reactions increase in a cell the larger the volume

Front 54

What are some adaptations by cells to maximize their SA:V ratio?

Back 54

Creating many more cell folds (Crista) in their cell membranes to maximize the SA which speeds up the processes of cellular metabolism

Front 55

What is the function of a cell membrane?

Back 55

To protect the nucleus and filter particles

Front 56

What is the structure of a phospholipid?

Back 56

made up of 2 hydrophobic tails for each hydrophilic head. Structure is flexible and changes shape easily due to fluidity. Structure is strong due to attraction between hydrophobic tails

Front 57

How are integral proteins different from peripheral proteins?

Back 57

integral protein is inside the lipid bilayer, where peripheral protein are attached to the hydrophilic heads of the bilayer

Front 58

What are the 4 functions of membrane bound proteins?

Back 58

a) Immune system receptors (b) act as carrier proteins to transport molecules across cell membranes (c) signal transduction (d) cell-cell adhesion

Front 59

Why are carrier proteins and channel proteins different types of transport proteins?

Back 59

both are integral membrane proteins involved in moving things across the membrane and both have specific targets, but carrier proteins transport molecules by changing shape while channel proteins are like tubes to transport. Carrier proteins are saturated, while channel proteins are unsaturated

Front 60

Why are phospholipids in the membrane fluid?

Back 60

fluid membranes allow cells to be dynamic and responsive in their environment

Front 61

Why are some fatty acids considered saturated while others are unsaturated?

Back 61

saturated fatty acids are evenly filled with hydrogen, while double bonds in the hydrocarbon chain create unsaturated fatty acids

Front 62

What is the effect on the fluidity of being saturated or unsaturated?

Back 62

That the double bonds in the unsaturated require more room, so unsaturated is more fluid than saturated

Front 63

What is the function of the cholesterol molecules in the membrane?

Back 63

to provide protection from some water soluble molecules and provide structure in the cell membrane. Cholesterol also contains both a hydrophilic and hydrophobic

Front 64

What is adhesion?

Back 64

water is attracted to other substances (like how water sticks together)

Front 65

What is a carrier transport protein?

Back 65

can carry non charged substances across the membrane

Front 66

What is a channel carrier protein?

Back 66

can carry charged substances across the membrane

Front 67

What is cholesterol in the membrane?

Back 67

used to build and maintain the membrane, and modulates membrane fluidity

Front 68

What is an enzyme?

Back 68

a substance produced by a living organism that acts as a catalyst in reactions

Front 69

What is a fatty acid?

Back 69

carboxylic acid consists of hydrocarbon chain and terminal carboxyl groups

Front 70

What is a fluid mosaic?

Back 70

widely accepted idea: in plasma membranes proteins are embedded in lipids

Front 71

What is an integral protein?

Back 71

protein molecule is permanently attached to biological membrane

Front 72

What is a peripheral protein?

Back 72

adheres only temporarily to biological membrane that they're associated

Front 73

What is the phospholipid bilayer?

Back 73

thin membrane made of 2 layers of lipid molecules

Front 74

What is the plasma membrane?

Back 74

external fatty layer surrounding molecules of a cell

Front 75

What is a receptor?

Back 75

an organ or cell able to respond to stimuli and transmit signal

Front 76

What is saturated?

Back 76

containing no double or triple bonds

Front 77

2.1.1
Outline Cell Theory

Back 77

Cell theory states that: all living organisms are composed of cells. Multicellular organisms are composed of many cells, while unicellular are of one cell. Cells are the basic unit of structure in all organisms. Cells are the smallest units of life capable of surviving on their own. Cells come from pre-existing cells and never non-living material

Front 78

2.1.2
Discuss the evidence for the Cell Theory

Back 78

Scientists had experimented and found the cell was the smallest piece of living matter that could live on its own, and because of these units were so small, they were named cells. Cells could only reproduce from living matter, because cells cannot reproduce unless the cells can perform cell reproduction, which is impossible with a dead cell

Front 79

2.1.3
State that unicellular organisms carry out all functions of life.

Back 79

Unicellular organisms carry out al the functions of life including: metabolism, response, homeostasis, growth, reproduction, and nutrition.

Front 80

2.1.7
State that multicellular organisms show emergent properties

Back 80

multicellular organisms show emergent properties. cells can form different substances by specializing. Being one cell on its own is useless because of cells working together to function

Front 81

2.1.8
Explain that cells in multicellular organisms differentiate to carry out specialized functions by expressing some of their genes but not others

Back 81

Each cell in a multicellular organism contains all of the genes of that organism. The genes that are activated are different for each cell in our body to have its own function. Cells will develop in their own ways by differentiation which depends on the gene expression

Front 82

5.1.1
Define species, habitat, population, community, ecosystem, and ecology

Back 82

Species are a group of organisms which can interbreed and produce fertile offspring. Habitat is environment in which a species normally lives. Population is a group of organisms of same species. Community is a group of populations living and interacting in an area. Ecosystem is system of organisms and abiotics in area. Ecology is the study of relationships between biotic and abiotic and the environment they're in

Front 83

5.1.2
Distinguish between autotroph and heterotroph

Back 83

autotrophs are organisms that synthesize their organic molecules from simple inorganic substances where areas heterotrophs are organisms that obtain organic molecules from other organisms

Front 84

5.1.3
Distinguish between consumers, detritivores, and saprotrophs

Back 84

consumer is an organism that ingests other organic material that is living or recently killed. Detritivore is an organism that ingests nonliving organic matter. Saprotroph is an organism that lives on nonliving organic matter, secreting digestive enzymes into it an absorbing the products of digestion

Front 85

2.1.6
Explain the importance of the surface area to volume ratio as a factor limiting cell size.

Back 85

A large number of chemical reactions take place in the cytoplasm of cells. To be able to use this space effectively (like metabolizing) the surface area to volume ratio is very important. If it is too small, cells will overheat because metabolism is too fast. If the ratio is too big, the cell will die because metabolism is too slow

Front 86

2.4.1
Explain how the hydrophobic and hydrophilic properties of phospholipids help to maintain the structure of cell membranes.

Back 86

the phospholipid is both hydrophilic and hydrophobic. With a hydrophilic head pointed pointed out hydrophobic tailspointed in when the lipid is in water, the phospholipid can be flexible but strong. This is also in part that the hydrophobic tails like to be by each other. This is a stable structure with fluidity that allows the cell to change shape easily and maintain the structure of cell membranes

Front 87

2.4.3
List the functions of membrane proteins.

Back 87

Membrane proteins can act as hormone binding sites, electron carriers, pumps for active transport, channels for passive transport, and enzymes. Also, they can be used for cell to cell communication and cell adhesion.

Front 88

2.4.8
Describe how the fluidity of the membrane allows it to change shape, break and reform during endocytosis and exocytosis.

Back 88

the phospholipids int he cell membrane are not solid but are in a fluid state allowing the membrane to change its shape and also vesicles to fuse with. This means substances can enter the cell via endocytosis and exit via exocytosis. The membrane then returns to its original states. In exocytosis, the vesicles fuse with the membrane expelling their content outside the cell. The membrane then goes back to its original state. Endocytosis is a similar process which involves the pulling of the plasma membrane inwards so that a vesicle is pinched off and then this vesicle can carry its content to anywhere in the cell

Front 89

3.1.1 – State that the most frequently occurring elements in living things are carbon, hydrogen, oxygen and nitrogen.

Back 89

Carbon, hydrogen, oxygen and nitrogen are the most frequently occurring chemical elements in living things. All of these elements form macromolecules essential to life, and are macronutrients/important components in all biochemical molecules.This is why all organisms are carbon-based life-forms.

Front 90

3.1.2 – State that a variety of other elements are needed by living organisms, including sulfur, calcium, phosphorus, iron and sodium.

Back 90

A variety of other elements are needed by living organisms including sulfur, calcium, phosphorus, iron and sodium to maintain homeostasis in living organisms with the most significant function being bonding to oxygen.

Front 91

3.1.3 – State one role for each of the elements mentioned in 3.1.2

Back 91

Sulfur is needed for the synthesis of two amino acids. Calcium acts as a messenger by binding to calmodulin and a few other proteins that regulate transcription and other processes in the cell. Phosphorus is a part of DNA molecules and is also part of the phosphate groups in ATP. Iron is needed for the synthesis of cytochromes that are proteins used during electron transport for aerobic cell respiration. Sodium upon entering the cytoplasm raises the solute concentration, which allows water to enter by osmosis.

Front 92

3.1.4 – Draw and label a diagram showing the structure of water molecules to show their polarity and hydrogen bond formation.

Back 92

The Hydrogen in this diagram are positive and the oxygen carries a -2 polarity. To let the Oxygen form bonds with other Hydrogen after becoming neutral, it must connect by a covalent bond to the Hydrogen of another neutral water molecule.

Front 93

3.1.5 – Outline the thermal, cohesive and solvent properties of water.

Back 93

Thermal properties of water include heat capacity, boiling and freezing points and the cooling effect of evaporation. Due to water’s substantial heat capacity, a significant amount of energy is needed to increase its temperature and break the many sturdy Hydrogen bonds included in its structure. This is why the temperature of water maintains homeostasis easily.
Water has a high boiling and freezing point. It boils at 100 C due to strong hydrogen bonds that need to break before liquid can change to gas. Due to low density in the water as it reaches its freezing point, ice will float.
To evaporate water below the boiling temperature, Hydrogen bonds need to break.
Cohesion is the effect of hydrogen bonds holding the water molecules together. Capillary Action is due to cohesion. The polarity of water creates a magnetism in water, allowing for strong adhesion between water molecules.
The solvent properties of water helps the many different molecules can adhere to it due to its polarity.

Front 94

3.1.6 – Explain the relationship between the properties of water and its uses in living organisms as a coolant, medium for metabolic reactions and transport medium.

Back 94

Water can evaporate at temperatures below the boiling point with breaking Hydrogen bonds. Evaporation of water cools mammalian bodies by sweat and plant leafs by transpiration. This is from using the heat energy to to break the hydrogen bonds. The solvent properties of water allow many different substances to attach to it due to its polarity and so substances can be carried in the blood and sap of plants as they dissolve in water. By doing these processes and having strong homeostasis, water can produce good metabolic reactions.

Front 95

3.2.1 – Distinguish between organic and inorganic compounds.

Back 95

Organic compounds are compounds that contain carbon. Inorganic compounds are the ones that don’t contain carbon. There are few compounds found in living organisms that do not contain carbon, but are considered as inorganic compounds. These include carbon dioxide, carbonates and hydrogen carbonates.

Front 96

3.2.2 – Identify glucose, ribose and fatty acids from diagrams showing their structures.

Back 96

Glucose is a monosaccharide and is the easiest sugar to digest because it can be easily made into blood sugar. The glucose has a structure of five OH molecules, with the fifth hanging off of an Oxygen molecule. Glucose is a carbohydrate macromolecule.


Ribose is a Pentose molecule, and has all of its hydroxyl groups on the same side. Ribose is a Nucleic Acid macromolecule. When mutated into deoxyribose, ribose can be part of a DNA strand.

Fatty Acids are a macromolecule broken up into: triglycerides, phospholipids, and steroids. This group needs more oxygen to release energy.

Front 97

3.2.3 – List three examples each of monosaccharides, disaccharides and polysaccharides.

Back 97

Glucose, galactose and fructose are all monosaccharides.
Maltose, lactose and sucrose are all disaccharides.
Starch, glycogen and cellulose are all polysaccharides.

Front 98

3.2.4 – State one function of glucose, lactose and glycogen in animals, and of fructose, sucrose and cellulose in plants.

Back 98

In animals, glucose is used as an energy source for the body and lactose is the sugar found in milk which provides energy to new borns until they are weaned. Finally, glycogen is used as an energy source (short term only) and is stored in muscles and the liver.
In plants, fructose is what makes fruits taste sweet that attracts animals that then eat the fruits and disperse the seeds found in the fruits. Sucrose is used as an energy source for the plant whereas cellulose fibers are what make the plant cell wall strong.

Front 99

3.2.5 – Outline the role of condensation and hydrolysis in the relationships between monosaccharides, disaccharides and polysaccharides; between fatty acids, glycerol and triglycerides; and between amino acids and polypeptides.

Back 99

Condensation reactions occur when molecules are covalently joined together and water is formed as a by-product. In carbohydrates, that bond is called glycosidic linkage. The opposite of condensation reaction is hydrolysis reaction, which requires a water molecule to break a covalent bond between two subunits. Monosaccharides are single monomers that are joined to form disaccharides, while sugars containing multiple subunits are called polysaccharides.

Front 100

3.2.6 – State three functions of lipids.

Back 100

Lipids can be used for energy storage in the form of fat in mammals and oil in plants.
Lipids can be used as heat insulation as fat under the skin reduces heat loss.
Lipids allow buoyancy as they are less dense than water and help some animals float in water.

Front 101

3.2.7 – Compare the use of carbohydrates and lipids in energy storage.

Back 101

Carbohydrates and lipids can both be used as energy storage, however carbohydrates are normally used for short-term storage whereas lipids are used for long-term storage. Unlike lipids, carbohydrates are soluble in water. This makes carbohydrates easier to transport around the body (from and to storage). Also, carbohydrates are a lot faster by being more rapidly digested their energy is useful if the body requires energy.

As for lipids, they are insoluble which makes them more difficult to transport however because they are insoluble, lipids do not have an effect on osmosis which prevents problems within the cells in the body. They also contain more energy per gram than carbohydrates that make lipids a lighter store compared to a store of carbohydrates equivalent in energy.

Front 102

Adhesion

Back 102

being attracted to other substances

Front 103

Anion

Back 103

negatively charged ion

Front 104

Atom

Back 104

Basic unit of chemical element/smallest unit of matter

Front 105

Calcium

Back 105

– the chemical element of atomic number 20, needed for survival of organisms

Front 106

Capillary Action

Back 106

ability of a liquid to flow in narrow spaces without the assistance of, and in opposition to external forces like gravity. Eg. water uses its magnetism and adhesive/cohesive properties to pull water through stem of plant from roots to top

Front 107

Carbohydrate

Back 107

any large group of compounds occurring in foods and living tissues containing: sugars, starch, and cellulose. They contain hydrogen and oxygen in the same ratio as water (2:1) and can typically be broken down to release energy in the animal body.

Front 108

Carbon

Back 108

chemical element of atomic number 6, found in almost all living or formerly living matter.

Front 109

Carboxyl

Back 109

of or denoting the acid radical COOH, present in most organic acids. The –COOH group where a carbon atom is doubly bonded to an oxygen atom and singly bonded to an OH group.

Front 110

Cation

Back 110

positively charged ion

Front 111

Cellulose

Back 111

insoluble substance that is the main constitute of plant cell walls and of vegetable fibers. It is a polysaccharide consisting of chains of glucose monomers.

Front 112

Chemical bond

Back 112

an electrical force linking atoms, creating molecules

Front 113

Chemical Formula

Back 113

representation of a substance using symbols for its constituent elements.

Front 114

Chitin

Back 114

fibrous substance consisting of polysaccharides and forming the major constituent in the exoskeleton of arthropods and walls of fungi.

Front 115

Cholesterol

Back 115

important constituent of cell membranes and precursors of other steroid compounds.

Front 116

Cis

Back 116

denoting or relating to a molecular structure in which two particular atoms or groups lie on the same side of a given plane in a molecule, in particular denoting an isomer in which its substituents at opposite ends of a carbon-carbon double bond are on the same side of the bond.

Front 117

Cohesion

Back 117

– sticking together of particles of the same substance

Front 118

Condensation Reaction

Back 118

– polymerization of monomers in which two or more molecules combine, resulting in the production of water and product

Front 119

Covalent Bond

Back 119

chemical bond that involves sharing a pair of electrons between atoms in a molecule

Front 120

Dehydration Synthesis

Back 120

process that joins molecules and produces water

Front 121

Deoxyribose

Back 121

sugar derived from ribose by replacing a hydroxyl group with hydrogen

Front 122

Disaccharide

Back 122

any of a class of sugars whose molecules contain two monosaccharide residues

Front 123

Electron

Back 123

stable subatomic particle with a charge of negative electricity, found in all atoms and acting as the primary carrier of electricity in solids.

Front 124

Element

Back 124

a substance that can’t be broken into two or more simpler substances. Some of them are put in the periodic table of elements which was made by Dmitri Mendeleev.

Front 125

Fatty acid

Back 125

carboxylic acid consisting of a hydrocarbon chain and a terminal carboxyl group, esp. any of those occurring as esters in fats and oils.

Front 126

Fructose

Back 126

a hexose sugar found esp. in honey and fruit

Front 127

Glucose

Back 127

a simple sugar that is an important energy source in living organisms and is a component of many carbohydrates

Front 128

Glycerol

Back 128

has three hydrophilic hydroxyl groups that are responsible for its solubility in water and its hydroscopic nature

Front 129

Glycogen

Back 129

substance deposited in bodily tissue as a store of carbohydrates. It is a polysaccharide that forms glucose on hydrolysis

Front 130

Hydrocarbon

Back 130

a compound of hydrogen and carbon, such as any of those that are the chief components of petroleum and natural gas

Front 131

Hydrogen

Back 131

chemical element atomic number 1, the lightest chemical element

Front 132

Hydrogen bond

Back 132

a weak bond between two molecules resulting from an electrostatic attraction between a proton in one molecule and an electronegative atom in the other

Front 133

Hydrolysis Reaction

Back 133

molecules of water are split into hydrogen cations and hydroxide anions in the process of a chemical mechanism

Front 134

Hydrophilic

Back 134

having a tendency to mix with, dissolve in, or be wetted by water

Front 135

Hydrophobic

Back 135

tending to repel or fail to mix with water

Front 136

Inorganic

Back 136

does not include carbon in its molecular structure

Front 137

Ionic Bond

Back 137

chemical bond in which one atom loses an electron to form a positive ion and the other atom gains an electron to form a negative ion

Front 138

Iron

Back 138

chemical element atomic number 26, ferrum, exists in wide range of oxidation states and is a necessary mineral for life

Front 139

Isomer

Back 139

each of the two or more compounds with the same formula but a different arrangement of atoms in the molecule and different properties.

Front 140

Lactose

Back 140

a sugar present in milk; disaccharide containing glucose and galactose units

Front 141

Lipid

Back 141

any of a class of organic compounds that are fatty acids in their derivatives and are insoluble in water but soluble in organic solvents.

Front 142

Macromolecule

Back 142

a molecule containing a very large number of atoms, such as a protein, nucleic acid, or synthetic polymer.

Front 143

Maltose

Back 143

a sugar produced by the breakdown of starch, e.g., by enzymes found in malt and saliva. It is a disaccharide consisting of two linked glucose units

Front 144

Matter

Back 144

generally anything that has mass and volume. Typically includes atoms and other particles that have mass.

Front 145

Monomer

Back 145

a molecule that can be bonded to other identical molecules to form a polymer

Front 146

Monosaccharide

Back 146

any of the class of sugars (e.g., glucose) that cannot be hydrolyzed to give a simpler sugar

Front 147

Neutron

Back 147

a subatomic particle of about the same mass as a proton but without and electric charge, present in all atomic nuclei expect those of ordinary hydrogen

Front 148

Nitrogen

Back 148

the chemical element of atomic number 7, gas necessary for life

Front 149

non-polar

Back 149

a compound or element whose electron capacity is satisfied. A neutral condition that will remain unreactive.

Front 150

Nucleic Acid

Back 150

a complex organic substance present in living cells, esp. DNA or RNA, whose molecules consist of many nucleotides linked in a long chain

Front 151

Organic

Back 151

of, relating to, or derived from living matter is not correct... It is a substance based on carbon and must include carbon in its molecular structure

Front 152

Oxygen

Back 152

Chemical element atomic number 8, nonmetallic element.

Front 153

Phosphate Group

Back 153

a functional group or radical comprised of phosphorus attached to four oxygen, and with a net negative charge. Involved in anabolic reactions and part of hydrophilic head of phospholipids in biological membrane

Front 154

Phospholipid

Back 154

a lipid containing a phosphate group in its molecule, e.g., lecithin

Front 155

Phosphorus

Back 155

highly reactive chemical element of atomic number 15

Front 156

Polar

Back 156

consisting of molecules with a dipole moment, ionic, type of covalent bond between two atoms in which electrons are shared unequally.

Front 157

Polymer

Back 157

a macromolecule composed of repeating structural units or chains typically connected by covalent chemical bonds.

Front 158

Polysaccharide

Back 158

any of a class of carbohydrates that are made of long chains of simple carbohydrates. Polymers of more than ten monosaccharides linked glycosidically branched or unbranched.

Front 159

Protein

Back 159

any of a class of nitrogenous organic compounds that consist of large molecules composed of one or more long chains of amino acids and are an essential part of all living organisms, esp. as structural components of body tissues.

Front 160

Proton

Back 160

stable subatomic particle occurring in all atomic nuclei, with a positive electric charge equal in magnitude to that of an electron, but of opposite sign.

Front 161

Ribose

Back 161

sugar of the pentose class that occurs widely in nature as a constituent of nucleosides and several vitamins and enzymes.

Front 162

Saturated

Back 162

consists of triglycerides containing no carbon-carbon double bonds

Front 163

Sodium

Back 163

the chemical element of atomic number 11, trace element that can affect the osmosis of water into the cell membrane

Front 164

Solute

Back 164

the minor component in a solution, dissolved in the solvent

Front 165

Solvent

Back 165

liquid in which a solute is dissolved to form a solution

Front 166

Specific heat

Back 166

the heat required to raise the temperature of the unit mass of a given substance by a given amount

Front 167

Starch

Back 167

a polysaccharide that functions as a carbohydrate store and is an important constituent of the human diet

Front 168

Sterol

Back 168

any of a group of naturally occurring unsaturated steroid alcohols, typically waxy solids

Front 169

Sucrose

Back 169

a compound that is the chief component of cane or beet sugar

Front 170

Sulfur

Back 170

the chemical element of atomic number 16, a yellow combustible nonmetal

Front 171

Surface tension

Back 171

– the tension of the surface film of a liquid caused by the attraction of the particles in the surface layer by the bulk of the liquid, which tends to minimize surface area

Front 172

Trace element

Back 172

a chemical element present only in minute amounts in a particular sample or environment. Required only in minute amounts by living organisms for normal growth.

Front 173

Trans

Back 173

denoting or relating to a molecular structure in which two particular atoms or groups lie on opposite sides of a given plane in a molecule, in particular denoting an isomer in which substituents at opposite ends of a carbon-carbon double bond are also on opposite sides of the bond

Front 174

Transparent

Back 174

allowing light to pass through so that objects can be distinctly seen

Front 175

Triglyceride

Back 175

an ester formed from glycerol and three fatty acid groups. Triglycerides are the main constituent of natural fats and oils, and high concentrations in the blood indicate an elevated risk of stroke.

Front 176

Unsaturated

Back 176

hydrocarbons that have double or triple covalent bonds between adjacent carbon atoms.

Front 177

Water

Back 177

two hydrogen bonded to one oxygen, and is the basis of the fluids of living organisms

Front 178

Wax

Back 178

class of hydrocarbons that are plastic (malleable) at normal ambient temperatures. Insoluble in water but soluble in petroleum based solvent.

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Nuceleotide

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molecules that consist of 3 parts: a sugar, phosphate group, and nitrogenous containing ring structure called nitrogenous base

Front 180

Deoxyribose

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sugar within DNA

Front 181

Ribose

Back 181

sugar within RNA

Front 182

RNA

Back 182

required catalyst to start replication

Front 183

tRNA

Back 183

transfer RNA, involved in decoding base sequence of AA during translation and carries AA

Front 184

rRNA

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ribosomal RNA, part of structure of ribosome where polypeptide synthesis occurs

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mRNA

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messenger RNA, carries info needed to synthesize a polypeptide and made in transcription

Front 186

ATP

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transports chemical energy within cells for metabolism

Front 187

Nitrogenous Base

Back 187

nitrogen containing ring structure

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Adenine Thymine Guanine Cytosine Uracil

Back 188

bases of RNA/DNA

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Complementary

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Hydrogen bond

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Double helix

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2 polymers of nucleotides, coiled around each other

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Histone

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Most common DNA proteins; don't form sheath around DNA strand

Front 192

Replication

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a process many catalysts are involved in to separate DNA helix and create new strands

Front 193

Helicase

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catalyst enzyme in replication

Front 194

DNA or RNA Polymerase

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links the phosphate of newest nucleotides to the sugar of new nucleotides before it, covalent bond, and is polymer of nucleotides

Front 195

Semi-conservative

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when dividing, DNA reuses 1 strand in each molecule and 1 new strand

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Ligase

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enzyme in DNA joins Okazaki fragment

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Okazaki fragments

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fragments on the lagging strand

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Codon

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sequence of 3 bases on the mRNA. Each codes for an AA to be added to polypeptides in translation

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Anticodon

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complementary to codon on tRNA can make attachment to mRNA

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Gene

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a distinct sequence of nucleotides forming part of a chromosome

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None Coding Sequence

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3 codons/stop codon

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Human Genome Project

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has led us to understand that there are a number of recognizable patterns observed in DNA

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Start code/stop code

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first or last 3 codons of mRNA for an AA sequence in translation

Front 204

Loci

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the position of a gene or mutation of a chromosome

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Polypeptide

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compose a protein, synthesized by mRNA, sequence of AA

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Amino Acid

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simple organic compound containing both a carboxyl (COOH) and an amino (NH2) group

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Enzyme

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biological catalysts that speed up biochemical reactions

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Spindle Fibers

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separates the chromosomes into daughter cells during cell division. It is part of the cytoskeleton in eukaryotic cells

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Cell Cycle

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series of events leading to the cell's division and replication

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Mitosis

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the process of nuclear division in a cell in steps of: prophase, metaphase, anaphase, telophase, cytokinesis

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Meiosis

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a type of cell division that results in two daughter cells each with half the chromosome number of the parent cell

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Cell phases

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prophase, metaphase, anaphase, telophase, cytokinesis

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Chromatin

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the material of which the chromosomes of organisms other than bacteria are composed. It consists of protein, RNA, and DNA.

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Sister Chromatids

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2 identical copies of a chromatin connected by a centromere

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Centromere, telomere

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Connects the 2 identical copies of a chromatin

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Cleavage furrow

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constriction of the cell membrane at the equator of the cell that marks the beginning of cytokinesis in animal cells and the cell divides as the furrow deepens

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Cell plate

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in plants, a membrane-bound space produced during cytokinesis by the vesicles of the Golgi apparatus. The plate fuses with the plasma membrane, dividing the cell into two compartments

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3 prime

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the end of the deoxyribose's sugar rings

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5 prime

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the end of the phosphate group

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reverse transcriptase

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an enzyme that catalyzes the formation of DNA from an RNA template in reverse transcription

Front 221

density dependent inhibition

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the phenomenon exhibited by most normal (anchorage dependent) animal cells in culture that stop dividing once a critical cell density is reached

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anchorage dependence

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dependence of cell growth on attachment to a substratum

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tumor

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abnormal growth of cells

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malignant/benign

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malignant is uncontrolled growth while benign is not cancerous

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pyrimidine/purine

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basis of the bases in RNA/DNA... thymine, uracil and cytosine are pyrimidines. Adenine and guanine are purines.

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nucleosomes

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group of histones (8) forming octomers

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interon/exon

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remaining portion of mRNA in transcription "-ase" exons. Interspersed sequences in mRNA not contributing to formation of polypeptides.

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recombination

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rearrangement of genetic material, especially by crossing over in chromosomes or by the artificial joining of segments of DNA from different organisms.

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DNA anatomy

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nucleotides in each strand are joined by covalent bonds, alternating sugar and phosphate molecules form a backbone for each strand, the 2 strands are held together by hydrogen bonds between nitrogenous bases, 2 strands in helix, contains: adenine, thymine, guanine, and cytosine in nitrogenous bases. Adenine bonds to Thymine and Guanine bonds to Cytosine.

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3.3.1 Outline DNA nucleotide structure in terms of sugar (deoxyribose), base and phosphate.

Back 230

A nucleotide is made of the sugar deoxyribose, a base (which can be either adenine, guanine, cytosine or thymine) and a phosphate group. Below is a representation of a nucleotide.

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3.3.2 – State the names of the four bases in DNA.

Back 231

Adenine, Thymine, Guanine, Cytosine

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3.3.3 – Outline how DNA nucleotides are linked together by covalent bonds into a single strand.

Back 232

Nucleotides are linked to one another to form a strand. A covalent bond forms between the sugar of one nucleotide and the phosphate group of another nucleotide.

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3.3.4 – Explain how a DNA double helix is formed using complementary base pairing and hydrogen bonds.

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DNA is made up of two nucleotide strands. The nucleotides are connected together by covalent bonds within each strand. The sugar of one nucleotide forms a covalent bond with the phosphate group of another. The two strands themselves are connected by hydrogen bonds. The hydrogen bonds are found between the bases of the two strands of nucleotides. Adenine forms hydrogen bonds with thymine whereas guanine forms hydrogen bonds with cytosine. This is called complementary base pairing.

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3.3.5 – Draw and label a simple diagram of the molecular structure of DNA.

Back 234

Without a picture here... Imagine the left of the ladder starting with a phosphate, then bonding covalently to a pentose sugar (deoxyribose) and then another phosphate. This continues down the ladder and on the other side of the ladder, the 3 prime starts the same way, only missing its first phosphate. The nucleotides, making half of the ladder, composed of: one phosphate covalently bonded to pentose sugar, which is also bonded to a nitrogenous base. On the other half of the ladder it will be the same, but with the corresponding nitrogenous base. If A and T are the nitrogenous bases, a double hydrogen bond will be used. If C and G are used, a triple hydrogen bond will be used. The 5 prime will end in 3 prime and the 3 prime will end in 5 prime, making up for the lagging and leading.

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3.4.1 – Explain DNA replication in terms of unwinding the double helix and separation of the strands by helicase, followed by formation of the new complementary strands by DNA polymerase.

Back 235

DNA Replication is semi-conservative as both of the DNA molecules produced are formed from an old strand and a new one. The first stage of DNA replication involves the unwinding of the double strand of DNA (DNA double helix) and separating them by breaking the hydrogen bonds between the bases. This is done by the enzyme helicase. Each separated strand now is a template for the new strands. There are many free nucleotides around the replication for which to bond to the template strands. The free nucleotides form hydrogen bonds with their complimentary base pairs on the template strand. Adenine will pair up with thymine and guanine will pair up with cytosine. DNA polymerase is the enzyme responsible for this. The new DNA strands then rewind to form a double helix. The replication process has produced a new DNA molecule which is identical to the initial one.

Front 236

3.4.2 – Explain the significance of complementary base pairing in the conservation of the base sequence of DNA.

Back 236

Complementary base pairing is very important in the conservation of the base sequence of DNA. This is because adenine always pairs up with thymine and guanine always pairs up with cytosine. As DNA replication is semi-conservative (one old strand an d one new strand make up the new DNA molecules), this complementary base pairing allows the two DNA molecules to be identical to each other as they have the same base sequence. The new strands formed are complementary to their template strands but also identical to the other template. Therefore, complementary base pairing has a big role in the conservation of the base sequence of DNA.

Front 237

3.4.3 – State that DNA replication is semi-conservative.

Back 237

DNA replication is semi-conservative as both of the DNA molecules produced are formed from an old strand and a new one.

Front 238

3.5.1 – Compare the structure of RNA and DNA.

Back 238

DNA and RNA both consist of nucleotides which contain a sugar, a base and a phosphate group. However there are a few differences. Firstly, DNA is composed of a double strand forming a helix whereas RNA is only composed of one strand. Also the sugar in DNA is deoxyribose whereas in RNA it is ribose. Finally, both DNA and RNA have the basis: adenine, guanine and cytosine; but DNA contains thymine while RNA contains uracil.

Front 239

3.5.2 – Outline DNA transcription in terms of the formation of an RNA strand complementary to the DNA strand by RNA polymerase.

Back 239

DNA transcription is the formation of an RNA strand, which is complementary to the DNA strand. The first stage of transcription is the uncoiling of the DNA double helix. Then, the free RNA nucleotides start to form an RNA strand by using one of the DNA strands as a template. This is done through complementary base pairing, however in the RNA chain, the base thymine is replaced by uracil. RNA polymerase is the enzyme involved in the formation of the RNA strand and the uncoiling of the double helix. The RNA strand then elongates and separates from the DNA template. The DNA strands then reform a double helix. The strand of RNA formed is called messenger RNA.

Front 240

3.5.3 – Describe the genetic code in terms of codons composed of triplets of bases.

Back 240

A triplet of bases (3 bases) forms a codon. Each codon codes for a particular amino acid. Amino acids in turn link to form proteins. Therefore DNA and RNA regulate protein synthesis. The genetic code is the codons within DNA and RNA, composed of triplets of bases which eventually lead to protein synthesis.

Front 241

3.5.4 – Explain the process of translation, leading to polypeptide formation.

Back 241

Translation is the process in which proteins are synthesized. It uses ribosomes, messenger RNA which is composed of codons and transfer RNA which has a triplet of bases called the anticodon. The first stage of translation is the binding of messenger RNA to the small subunit of the ribosome. The transfer RNA’s have a specific amino acid attached to them which corresponds to their anticodons. A transfer RNA molecule will bind to the ribosome however its anticodon must match the codon on the messenger RNA. This is done through complementary base pairing. These two form a hydrogen bond together. Another transfer RNA molecule then bonds. Two transfer RNA molecules can bind at once. Then the two amino acids on the two transfer RNA molecules form a peptide bond. The first transfer RNA then detaches from the ribosome and the second one takes its place. The ribosome moves along the messenger RNA to the next codon so that another transfer RNA can bind. Again, a peptide bond is formed between the amino acids and this process continues. This forms a polypeptide chain and is the basis of protein synthesis.

Front 242

Enzyme

Back 242

a substance produced by a living organism that acts as a catalyst to bring about a specific biochemical reaction.

Front 243

Active site

Back 243

a region or an enzyme that binds to a protein or other substance during a reaction

Front 244

Enzyme-substrate specificity

Back 244

the enzyme can only work for one substrate at a time

Front 245

pH

Back 245

a figure expressing the acidity or alkalinity of a solution on a logarithmic scale on which 7 is neutral, lower values are more acidic, and higher values are more alkaline.

Front 246

substrate concentration

Back 246

as the concentration of substrate increases, the rate of reaction also increases until the point of saturation occurs.

Front 247

induced fit model

Back 247

enzymes are proteins that catalyze (i.e., increase the rate of) chemical reactions. in enzymatic reactions, the molecules at the beginning of the process are called substrates, and the enzyme converts them into different molecules, called the products. If the substrate does not fit exactly into the active site in an enzyme, and the enzyme must work to fit with the substrate, this is induced fit.

Front 248

denaturation

Back 248

to unfold a protein or break it up, changing its usual 3D structure. Proteins can be denatured by chemical action, heat or even agitation of a protein solution.

Front 249

lactase

Back 249

an enzyme that catalyzes the hydrolysis of lactose to glucose and galactose

Front 250

lock and key model

Back 250

enzymes are proteins that catalyze (i.e., increase the rate of chemical reactions. In enzymatic reactions, the molecules at the beginning of the process are called substrates, and the enzyme converts them into different molecules, called the products.

Front 251

coenzyme

Back 251

a nonprotein compound that is necessary for the functioning of an enzyme

Front 252

activation energy

Back 252

the minimum quanitity of energy that the reacting species must possess in order to form an 'activated complex' or 'transition state' before proceeding to become products.

Front 253

lactose intolerance

Back 253

a genetic trait characterized by the absence of the enzyme lactase, which breaks down lactose, the main sugar in milk and other dairy products.

Front 254

transition state

Back 254

transition state speculation assumes, that during an alkali-containing reaction, the reactants have been initially altered into a magnitude activated passing from a singular to another state and afterwards they get converted into the last products.

Front 255

inhibitor

Back 255

a chemical compound that has the effect of blocking or slowing an enzymatic reaction

Front 256

allosteric interactions and site

Back 256

allosteric regulation is the regulation of an enzyme or other protein by binding an effector molecule at the protein's allosteric site (that is, a site other than the protein's active site)

Front 257

3.6.1 Define enzyme and active site

Back 257

Enzymes are globular proteins which act as catalysts of chemical reactions. Active sites are regions on the surfaces of enzymes to which substrates bind and which catalyzes a chemical reaction involving the substrates.

Front 258

3.6.2 Explain enzyme-substrate specificity. The lock-and-key model can be used as a basis for the explanation. Refer to the 3D structure.

Back 258

The active site of an enzyme is very specific to its substrates as it has a very precise shape. This results in enzymes being able to catalyze only certain reactions as only a small number of substrates fit into the active site. This is called enzyme-substrate specificity. For a substrate to bind to the active site of an enzyme it must fit into the active site and be chemically attracted to it. This makes the enzyme very specific to its substrate. The enzyme-substrate complex can be compared to a lock and key, where the enzyme is the lock and the substrate is the key.

Front 259

3.6.3 Explain the effects of temperature, pH and substrate concentration on enzyme activity.

Back 259

enzyme activity increases with an increase in temperature and usually doubles with every 10 degree rise. This is due to the molecules moving faster and colliding together more often in heat. However, at a certain point the temperature gets too high and the enzymes denature and stop functioning. This is due to the heat-causing vibrations within the enzyme destroying its structure by breaking bonds in the enzyme. Enzymes usually have an optimum pH at which they work most efficiently. As the pH diverges from the optimum, enzyme activity decreases. Both acid and alkali environments can denature enzymes. Enzyme activity increases with an increase in substrate concentration as there are more random collisions between the substrate and the active site. However, at some point, all the active sites are taken and increasing the substrate concentration will have no more effect on enzyme activity. As long as there are active sties available, an increase in substrate concentration will lead to an increase in enzyme activity.

Front 260

3.6.4 Define denaturation

Back 260

Denaturation is changing the structure of an enzyme (or other protein) so it can no longer carry out its function.

Front 261

3.6.5 Explain the use of lactase in the production of lactose-free milk.

Back 261

Lactose is the sugar found in milk. It can be broken down by the enzyme lactase into glucose and galactose. However, some people lack this enzyme and cannot break down lactose leading to lactose-intolerance. Lactose intolerant people need to drink milk that has been lactose reduced. Lactose-free milk can be made in two ways. The first involves adding the enzyme lactase to the milk so that the milk contains the enzyme. The second way involves immobilizing the enzyme on a surface or in beads of a porous material. The milk is then allowed to flow past the beads or surface with the immobilized lactase. This method avoids having lactose in the milk.

Front 262

Cell respiration

Back 262

cellular respiration is the process by which the chemical energy of "food" molecules is released and partially captured in the form of ATP

Front 263

ATP

Back 263

adenosine triphosphate: a nucleotide derived from adenosine that occurs in muscle tissue; the major source of energy for cellular reactions

Front 264

Glycolysis

Back 264

the breakdown of glucose by enzymes, releasing energy and pyruvic acid

Front 265

Pyruvate

Back 265

the product of glycolysis that enters into the mitochondria matrix to produce Acetyl-CoA, or it's used to produce lactic or alcohol fermentation in anaerobic conditions.

Front 266

Anaerobic

Back 266

production of ATP without oxygen builds up lactic acid. This is system is responsible for quick bursts of power and speed, but burns the fuel stored directly in your muscles creating lactic acid buildup.

Front 267

Lactate

Back 267

a metabolic intermediary produced (mainly) during intense exercise when the demand for energy in the muscles outstrips that which an be produced by aerobic metabolism. The point at which lactate begins to accumulate is often referred to as the "lactate threshold"

Front 268

Ethanol

Back 268

anaerobic respiration leaves a lot of energy in the form of ethanol or lactate molecules that the cell cannot use and must excrete.

Front 269

carbon dioxide

Back 269

a heavy odorless gas formed during respiration and by the decomposition of organic substances; absorbed from the air by plants in photosynthesis.

Front 270

Mitochondrion

Back 270

mitochondria are sometimes described as "cellular power plants" because they generate most of the cell's supply of ATP, used as a source of chemical energy. In addition to supplying cellular energy, mitochondria are involved in other tasks such as: signaling, cell differentiation, cell death as well as the control of the cell cycle and cell growth.

Front 271

ADP

Back 271

adenosine diphosphate - contains 2 phosphate and is weaker than ATP because of its sub energy levels.

Front 272

Aerobic

Back 272

This process using oxygen provides cells with needed ATP. Byproducts are carbon dioxide and water in this process.

Front 273

Oxidation/reduction

Back 273

any chemical reaction in which the transfer of electrons from one substance to another substance occurs. The substance losing electrons is oxidized and the substance gaining the electrons is reduced. Sometimes called "redox"

Front 274

Krebs Cycle

Back 274

the sequence of reactions by which most living cells generate energy during the process of aerobic respiration. It takes place in the mitochondria, consuming oxygen, producing carbon dioxide and water as waste products, and converting ADP to energy-rich ATP.

Front 275

Oxidative phosphorylation

Back 275

an enzymatic process in cell metabolism that synthesizes ATP from ADP.

Front 276

Electron-transport chain

Back 276

the third and final stage of glucose oxidation. A series of metabolic reactions that transport electrons from NAHD or FADH2 through a series of carriers resulting in ATP production.

Front 277

3.7.1 Define Cell respiration

Back 277

Cell respiration is the controlled release of energy from organic compounds in cells to form ATP.

Front 278

3.7.2 State that, in cell respiration, glucose in the cytoplasm is broken down into pyruvate, with a small yield of ATP.

Back 278

In cell respiration, the Krebs Cycle begins with intake of oxygen and breaks down sugars into energy through glycolysis into two pyruvates with yield of 2 ATP and 2 NADH.

Front 279

3.7.3 Explain that, during anaerobic cell respiration, pyruvate can be converted in the cytoplasm into lactate, or ehtanol and carbon dioxide, with no further yield of ATP. Mention that ethanol and carbon dioxide are produced in yeast, whereas lactate is produced in humans.

Back 279

In anaerobic cell respiration, the pyruvate stays in the cytoplasm, and in humans, is converted into lactate that is removed from the cell. In yeast, the pyruvate is converted into carbon dioxide and ethanol. In either case, no ATP is produced.

Front 280

3.7.4 Explain that, during aerobic cell respiration, pyruvate can be broken down in the mitochondrion into carbon dioxide and water with a large yield of ATP.

Back 280

In aerobic cell respiration, the Krebs Cycle begins with intake of oxygen and starts glycolysis which breaks sugars into two pyruvates with a yield of 2 ATP and 2 NADH.

Front 281

RuBP

Back 281

Ribulose Biphosphate is the 5 carbon chemical that combines w/ CO2 at the beginning of the Calvin Cycle

Front 282

Wavelength Chlorophyll

Back 282

is the molecule that absorbs sunlight and uses its energy to synthesize carbohydrates from CO2 and water in photosynthesis

Front 283

CAM plant

Back 283

standing for crassulacean acid metabolism, this is a type of plant that employs an alternative photosynthesis pathway where CO2 enters the open stomata of the leaf during the night, allowing the stomata to close during the day to reduce water loss.

Front 284

Pigment

Back 284

the natural coloring matter of animals or plants tissue

Front 285

Absorption

Back 285

the process by which the products of digestion are transferred into the body's internal environment, enabling them to reach the cells.

Front 286

Photolysis

Back 286

a process whereby sunlight causes the chemical bonds in a molecule to break.

Front 287

Carbon fixation

Back 287

refers to any process through which gaseous carbon dioxide is converted into a solid compound. It mostly refers to the processes found in autotrophs, usually driven by photosynthesis, whereby carbon dioxide is changed into sugars.

Front 288

Biomass

Back 288

vegetation used as a fuel, or source of energy, especially if cultivated for that purpose. Total weight of plants.

Front 289

Cyanobacteria

Back 289

a division of microorganisms that are related to the bacteria but are capable of photosynthesis. They are prokaryotic and represent the earliest known form of life on the earth.

Front 290

Electromagnetic spectrum

Back 290

the entire range of light waves arranged according to their wavelength or the energy of their photons.

Front 291

Photoactivated

Back 291

process wherby something is prepared or excited for a subsequent reaction.

Front 292

Thylakoid, stoma, grana

Back 292

make up chloroplasts, where photosynthesis starts/ the matrix of a chloroplast, in which the grana are embedded/ the stacks of thylakoids embedded in the stoma of a chloroplast

Front 293

Chemiosmosis

Back 293

An energycouplling mechanism that uses energy stored in the form of a hydrogen ion gradient across a membrane to drive cellular work, such as the synthesis of ATP. Most ATP synthesis in cell occurs by chemiosmos.

Front 294

Calvin Cycle

Back 294

The biochemical pathway used by photosynthesis and chemosynthetic organisms to fix CO2 and synthesize sugars

Front 295

Cyclic photophosphorylation

Back 295

the production of ATP using the energy of sunlight. Only two sources of energy are available to living organisms: sunlight and oxidation-reduction (redox) reactions. All organisms produce ATP, which is the universal energy currency of life.

Front 296

3.8.1 State that photosynthesis involves the conversion of light energy into chemical energy.

Back 296

Chlorophyll traps light energy from the Sun and converts those photons into chemical energy. In the chloroplast, substrates of CO2 and H2O react with the photons absorbed from the Sun to make sugars and O2. Photosynthesis is observed in most often aquatic and terrestrial environments with light. At extreme altitudes, extremophiles can still photosynthesize. In exceedingly high temperatures, photosynthesis can be seen in geothermal active regions.

Front 297

3.8.2 State that light from the Sun is composed of a range of wavelengths (colours) –

Back 297

Light from the Sun is composed of a range of wavelengths. There is a visible spectrum of light ranging from a multitude of colors. When these colors are combined together they create the “white light” we associate with sunlight. The shortest of these wavelengths on the visible spectrum of light are blues, which give off the most energy. The longest wavelengths are reds, which give off the least energy in the visible spectrum of light.

Front 298

3.8.3 State that chlorophyll is the main photosynthetic pigment –

Back 298

Chlorophyll is the main photosynthetic pigment. This is where light energy is trapped and turned into chemical energy. The head of the molecule is polar and composed of a ring structure. At the heart of this ring structure is the inorganic ion magnesium. This is the light-trapping region of the chlorophyll molecule. The tail of the molecule is non polar and embeds itself in membranes in the chloroplast.
There are other pigments, reds, yellows and browns but these are only usually seen in the experimental chromatography or in the autumnal colors of deciduous trees in a temperate climate.

Front 299

3.8.4 Outline the differences in absorption of red, blue and green light by chlorophyll. –

Back 299

Chlorophyll can absorb red and blue light more than green. Chlorophyll cannot absorb green light and so instead reflects it making leaves look green.

Front 300

3.8.5 State that light energy is used to produce ATP, and to split water molecules (photolysis) to form oxygen and hydrogen. –

Back 300

Light is absorbed by chlorophyll molecules (green) on membranes inside the chloroplast. This is the light trapping stage in which photons of light are absorbed by the chlorophyll and turned into chemical energy (electrons). The chemical energy (electrons) is trapped in making ATP. In photolysis, Water used in photosynthesis is split which provides: hydrogen for the formation of organic molecules. (C6H12O6). Oxygen gas is given off.

Front 301

3.8.6 State that ATP and hydrogen (derived from the photolysis of water) are used to fix carbon dioxide to make organic molecules. –

Back 301

H+ from the splitting of water are combined with carbon dioxide to form organic compounds like sugar. Bonds are formed between the carbon, hydrogen and oxygen using the energy from ATP (which came form the sun). C, H, O are enough to form lipids and carbohydrates. With a Nitrogen source amino acids and therefore proteins can be made.
Plants have this remarkable ability to manufactory all their own organic molecules and by definition all the basic organic molecules required by all life forms.

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3.8.7 Explain that the rate of photosynthesis can be measured directly by the production of oxygen or the uptake of carbon dioxide, or indirectly by an increase in biomass. –

Back 302

Photosynthesis can be measured in many ways as it involves the production of oxygen, the uptake of carbon dioxide and an increase in biomass. For example, aquatic plants release oxygen bubbles during photosynthesis and so these can be collected and measured. The uptake of carbon dioxide is more difficult to measure so it is usually done indirectly. When carbon dioxide is absorbed from water the pH of the water rises and so this can be measured with pH indicators or pH meters. Finally, photosynthesis can be measured through an increase in biomass. If batches of plants are harvested at a series of times and the biomass of these batches is calculated, the rate increase in biomass gives an indirect measure of the rate of photosynthesis in the plants.

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3.8.8 Outline the effects of temperature, light intensity and carbon dioxide concentration on the rate of photosynthesis. –

Back 303

As temperature increases, the rate of photosynthesis increases more and more steeply until the optimum temperature is reached. If temperature keeps increasing above the optimum temperature then photosynthesis starts to decrease very rapidly.
As light intensity increases so does photosynthesis until a certain point. At high light intensities photosynthesis reaches a plateau and so does not increase any more. At low and medium light intensity the rate of photosynthesis is directly proportional to the light intensity.
As the carbon dioxide concentration increases so does the rate of photosynthesis. There is no photosynthesis at very low levels of carbon dioxide and at high levels the rate reaches a plateau.