Biology 112 Midterm #1

Front 1

Cell Theory

Back 1

All organisms made from cell, it is the fundamental unit of life, all cells come from preexisting cells.

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Homeostasis

Back 2

Maintains stable environment and water levels for cells to function properly

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Natural Selection

Back 3

Within a population, organisms that are able to adapt better in their environment are more likely to survive. This is a key mechanism to Charles Darwin's Theory of Evolution.

Front 4

Eukaryote cells

Back 4

Usually multicellular, contains internal components, a nucleus is present; sexual production through mitosis and meiosis.

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Prokaryotic cells

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Lacks a nucleus (nucleoid in which it holds the genetic information), unicellular (Archaea and bacteria), lack internal components, and small in size. Since it has a small size, there is a higher metabolic rate due to high surface area/volume ratio.

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Laws of Thermodynamics (state and relation to cell biology)

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Energy cannot be created nor destroyed but only transformed into other forms of energy. Cells use energy from the environment (for example the sun) and convert it into chemical energy for energy that organelles may use. Transformation of energy is associated with degree of disorder in the universe. Cells require large amounts of energy in order to control itself. Excess energy is released and small molecules move (which results in an increase of entropy)

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Metabolism

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Makes ATP which is produced by the mitochondria (breaks down macromolecules for energy)

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Central Dogma

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Explanation of genetic information flow. DNA contains the genetic information. Through transcription a copy of the DNA strand is formed to create an RNA strand. Translation is taking mRNA and form a sequence of amino acids (eventually the formation of proteins)

Front 9

Environmental selection

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Individuals may be different w h others due to environmental differences (season differneces and locations)

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Genetic variation

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Variation of alleles and genes which creates diversity in a population (big or small)

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Tree of life

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Evolution can be represented by a tree (tree of life: evolutionary relationships between organisms->Eukarya, Prokarya, and Archaea

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Ecology

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The study of how organisms interact with each other and their physical environment. (No organism exists in isolation)

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Symbiosis

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The mutalistic relationship between two organisms (paratism- host is harmed; predation- prey is lethally killed)

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Mutations

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They often create new adaptations in species as well as environmental/genetic factors which creates the branches of life

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Features of organisms that shape ecological systems

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Anatomy, physiology, and behavior shapes the ecological systems

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How did humans affect earth

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Humans have existed as homo sapiens 4 billions years ago. Now at a population of over 7 billion, we are leaving ecological footprints and technological advances. Understanding biology requires understanding through an integrated perspective.

Front 17

What makes up an atom

Back 17

Proton, electron, and neutron

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Isotopes

Back 18

Atoms of the same elements but different number of neutrons

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Electronegativety

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The ability of atoms to attract electrons

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Valence electrons

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Most outmost electrons which tend to have the highest amount of energy

Front 21

Characteristics of water

Back 21

Polar molecules (have slightly charged negative ends and slightly charged positive ends)

Good solvents(capable of dissolving many substances)

Hydrogen bonds (creates high cohesion, surface tension)

Thermal properties (has a high heat capacity which moderates organisms body temperature)

Front 22

Carbon

Back 22

Most abundant element, makes up all organic molecules, can form up to four covalent bonds, form rings and long chains.

Front 23

Hydrogen bond

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A hydrogen that has a slight positive charge and is covalently bonded to a more electronegative atom (N or O)

Front 24

6 most abundant elements

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Carbon, Oxygen, Hydrogen, Nitrogen, Phosphorus, Sulphur

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Isomers

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Two or more compounds with the same formula but different structures.

Front 26

Types of macromolecules

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Proteins (amino acids), Lipids (Fatty acids/glycerol), carbohydrates (monosaccharides), and Nucleic acid (Nucleotides)

Front 27

What is part of the Protein structure

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Alpha carbon, R group (side group), Carboxyl group and amino group

Front 28

What dictates the size of the cell

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Diffusion (a more flatter shape) surface/volume ratio (smaller cell or dividing up cytoplasm to create more SA) and diffusion (increased concentration inside the cell would increase the rate of osmosis)

Front 29

Stages of Bacteria cell growth

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Lag- cells are not adapting to new cell growth,preparing for replication and division

Exponential- Cells are dividing (binary fission) at the same rate

Stationary- Cells dividing at the same rate as cells dying. Inhibitory levels of waste products are accumulating and resources start to run out

Death- Cells are dying, greater death rate, essential nutrients have become completely depleted.

Front 30

Types of macromolecule bonds

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Glycosidic bonds (carbohydrates) peptide bonds (amino acids) Phophodiester bond (nucleic acid- 5 phosphate and 3 hydroxyl group) ester linkage (lipids)

Front 31

Difference between Saturated and Unsaturated bonds

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Has no double bonds/has a double bond

Front 32

Describe the scientific method

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An observation is made, where you view the natural phenomenon and you make a hypothesis based on the reason of the observation. A prediction is made which would be tested in experiments. Once many experiments are successful, a hypothesis is developed into a theory.

Front 33

Van Der Waals

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Temporary binding of polarized molecules because of opposite charged

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Phospholipid structure

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Composed of glycerol attached to 2 fatty acid hydrophobic tails (non polar) and phosphate hydrophilic head (polar). Forms a bilayer in aqueous solutions.

Front 35

Predict the changes in cell growth in response to changes in environmental conditions.

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Temperature- minimal temperature slows growth while maximum kills cells

Nutrients- Exponential phase changes and stationary phase either lower or higher

Water- Essential nutrients, slower growing rate

pH- longer lag, less rapid growth, enzyme activity affected.

Front 36

Why is a reaction spontaneous when phospholipids are in aqueous solutions?

Back 36

Phospholipids are unique for their amphipathic nature, which forms into a bilayer. The interactions favor the structure. Lipid motion decreases, which then the movement of water molecules increase (hydrophobic effect). Self aggregation gives water more freedom thus a large entropy is resulted. Large entropy=-Gibbs free energy= reaction is spontaneous

Front 37

Function of cholesterol in cell membranes

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Increases/decreases membrane fluidity depending on the temperature. Low temperatures prevent phospholipids packing, increase mobility.

Front 38

Types of proteins and functions

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Transporters- moves ions across cell membrane, identifying cells openings for diffusion

Channels- Regulates movement of molecules in cell

Carriers- Facilitate movement by binding on protein site and grabs certain molecules.

Receptors- receive chemical signals from outside the cell

Enzymes- Catalyze chemical reactions

Anchors- Helps maintain cell structures and shape

Front 39

Describe the fluid mosaic module

Back 39

Plasma membrane (cytoplasm inside and extracellular fluid outside). Lipids and proteins make up the mosaic structure. "Fluid"part represents how some parts of the membrane can move around freely, if they are not attached to other parts of the cell. The "mosaic" part illustrates the 'patchwork' of proteins that is found in the Phospholipid Bilayer. Cholesterol maintains cell membrane stability in times of extreme temperatures.

Front 40

Integral membrane and peripheral membrane

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Integral- permanently attached to the membrane

Peripheral- temporarily associated with lipid bilayer

Front 41

What do cells need in the growth bacterium?

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Glucose (Carbon sources, concentration gradient), Salts and minerals (osmolarity), Phosphorus (ATP, phospholipids and nucleic acids) , Nitrogen (for proteins), H2O, Sulphur for protein structure.

Front 42

Cell wall/plasma membrane

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Cell Wall- helps maintain cell structure and inner contents of the cell; very rigid

Cell membrane- Regulates contents going inside and outside the cell (selectively permeable to certain molecules).

Front 43

Types of Passive transport (no energy required)

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Osmosis- high water concentration to low concentration through membrane proteins called aquaporins.

Diffusion- random movement from high to low concentration until equilibrium is established.

Facilitated Diffusion- diffusion uses carrier proteins (simple diffusion only requires concentration gradient).

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Explanation of Active transport (energy required)

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Usually process goes against the concentration (low concentration to high concentration). Primary transport move ions across in membrane creating difference in charge (ie Na+ and K+). Secondary (no ATP energy) uses protein pump which generates electrochemical gradient (due to greater positive charges on side of membrane with higher concentration of proteins).

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Which molecules are permeable/not permeable to cell membrane

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Permeable- hydrophobic molecules and small/ uncharged molecules (O2, H20, CO2, Ethanol)

Non permeable- large molecules and charged molecules (Glucose, Na+, H+)

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Electrochemical gradient

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Dictates the movement ions depending on the charge of the ions

Front 47

If you put water in one side and NaCl on the other side....

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Net movement will move to one side, but move in both directions constantly. Diffusion still occurs, but NO NET MOVEMENT.

Front 48

Hypertonic solution

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Higher concentration of solute in extracellular cell (lower concentration of water), will cause red blood cells to shrivel

Front 49

Hypotonic solution

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Lower concentration of solute in extracellular cell(higher concentration of water), will cause red blood cells to swell and burst.

Front 50

List some strategies that cells use to deal with the consequences of osmotic pressure build up as a result of the selective permeability of membranes

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Turgor pressure- make sure that the cell wall is rigid

Contractile vacuole- takes in excess water and releases it outside the cell

Cell wall is composed of cellulose, which strengthens the wall.

Front 51

Endoplasmic Reticulum

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Network of membranous tubules that is involved in protein and lipid synthesis

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Lysosomes

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Enzymes that break down macromolecules

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Golgi Apparatus

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Modifies proteins and lipids that are received from the endoplasmic reticulum.

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Cytoskeleton

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It forms a framework for the movement of organelles around the cytoplasm.

Front 55

Denaturing of proteins

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Due to high temperatures or unfavorable chemical changes (loses its quaternary structure)

Front 56

Chaperones

Back 56

specialized proteins that help protect slow protein folding and denatured proteins.

Front 57

Polarity

Back 57

asymmetric with two distinct chemical ends. Polypeptide extended by addition of a new amino acid and a residue to the C terminus because ribosome knows how to attach C to N.

Front 58

Classify amino acids on the basis of the hydrophilic/ hydrophobic properties of their side chains (R- groups).

Back 58

Generally Polar hyrdophilic has an oxygen or sulphur on side chain (in exception of Glycine, Serine, and cystenine). Hydrophobic side chains only carbons and hydrogens.

Front 59

Gibbs free energy (△G)

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Amount of energy required (endergonic+exergonic)

Front 60

Spontaneous reaction vs non spontaneous reaction

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Spontaneous reaction releases energy (negative G=catabolic reaction); breaks down macromolecules and produce ATP. Non spontaneous reaction requires an input of energy (positive G= anabolic reaction); build macromolecules from smaller units.

Front 61

Enthalpy vs Entropy

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Enthalpy: Total energy in the system; Entropy: degree of disorder in a system, motional movement

Front 62

Roles of enzymes in chemical reactions

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Reduces activation energy and increase rate of chemical reaction (transition state- time when chemical reactants are broken and products are formed) The △G value doesn't change in a presence of an enzyme

Front 63

How are the activity of enzymes affected?

Back 63

Inhibitors reduce the activity of enzymes (Competitive- enzyme binds to active site; non competitive- slows reaction by altering the shape of enzyme) and Activators increase the activity of enzymes.

Front 64

Why is ATP an important molecule in metabolism?

Back 64

It provides energy coupling between exergonic and endergonic reactions.

Front 65

Zinc, an essential trace element for most organisms, is present in the active site of the enzyme carboxypeptidase. The zinc most likely functions as a(n)

Back 65

cofactor necessary for enzyme activity.

Front 66

Allosteric enzyme

Back 66

Binds other than active site: regulation of biological process

Front 67

Explain how chemical energy is in molecular bonds

Back 67

Electrons far away from the nucleus have high potential energy. As shared electrons are more further apart, increase in potential energy.

Front 68

Characteristics of enzymes

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Reduce AE, highly specific, only bind to one specific substrate, form complexes with reactants and products

Front 69

Why are 3D shapes of proteins important

Back 69

so that the active site is in the correct location.

Front 70

Protein structures and sequences

Back 70

Primary- linear sequence of amino acids that determine folding (peptide bonds)

Secondary- Interactions of amino acids(alpha helices and beta sheets-hydrogen bonding which stabilize the structure of the helix-backbone)
Tertiary- Covalent interactions between R groups (disulfide bonds), non covalent bonds dipole dipole with polar groups and van der walls (induced) between non polar R groups. #D shape determined by interactions of side chains.

Quaternary- multiple polypeptides which would eventually form protein subunits

Front 71

Types of non covalent bonds

Back 71

Permanent Dipole- Permanent Dipole= polar molecules that are pulled due to electronegativety difference

Induced Dipole- Similar electronegativity (temporary charge when pulled towards a permanent dipole (ie HCL and Br-Br)

Ion dipole- charged dipole+fully charged ion

Ionic bond- amino acid side chains of opposite charges (NH3+, CO2-)

Front 72

When amino acid is changed...

Back 72

Consider the charge repulsion, which might prevent binding with protein

Front 73

How can your non covalent interactions change due to factors?

Back 73

Beyond optimal temperature will break bonds. change in pH will also change bonds. Detergents and amino acid substitution will definitely change the non covalent interactions.

Front 74

Why are non covalent bonds important

Back 74

They are weak bonds that can be easily broken