Biology Module 2

Front 1

Prokaryotes

Back 1

Single cells organisms with no membrane bound nucleus or organelles

Front 2

Eukaryotes

Back 2

Multicellular organisms with membrane bound organelles

Front 3

Nucleus

Back 3

Contains DNA, directs the synthesis of all proteins required by the cell and therefore controls the metabolic activities of the cell

Front 4

Nucleolus

Back 4

Area within the nucleus responsible for producing ribosomes necessary for protein synthesis

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Mitochondria

Back 5

Site of the final stages of cellular respiration. Double membrane bound to produce cristae and the fluid interior called the matrix. Inner membrane contains enzymes for aerobic respiration. Also contains mitochondrial DNA to produce it's own enzymes

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Vesicle

Back 6

Membranous sacs for storage and transport

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Lysosomes

Back 7

Specialised vesicles containing hydrolytic enzymes

Front 8

Cytoskeleton

Back 8

Network of fibres which gives a cell shape and structure. Organelles held in place by the cytoskeleton.

Composed of centrioles, microfilaments, microtubules and intermediate fibres

Front 9

Microfilaments (cytoskeleton)

Back 9

Contractile fibres of actin, responsible for cell movement and contraction during cytokinesis

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Microtubules (cytoskeleton)

Back 10

Globular tubulin proteins polymerise to form tubes that act as scaffold. They determine shape and acts a tracks for movement of organelles. Makes up spindle fibres

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Intermediate fibres (cytoskeleton)

Back 11

Give mechanical strength to cells

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Centrioles

Back 12

Component of the cytoskeleton, two associated centrioles form the centrosome involved in the assembly and organisation of spindle fibres

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Flagella Vs Cillia

Back 13

9+2 arrangement in structure

Flagella: Whip like, longer but fewer in number, generally used for movement.

Cillia: Hair like, used in sensory etc.

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Endoplasmic reticulum

Back 14

Network of membranes enclosib flattened sacs called cisternae. Connected to the nucleus.

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Smooth ER

Back 15

Responsible for lipid and carbohydrate synthesis and storage

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Rough ER

Back 16

Ribosomes bound to surface responsible for synthesis and transport of proteins. (Secretory cells contains more ER as they produce more enzymes etc.)

Front 17

Ribosomes

Back 17

No membrane, constructed of RNA. The site of protein synthesis

Front 18

Golgi Apparatus

Back 18

Similar in structure to SER. Modified and packages proteins into vesicles to leave the cell or lysosomes to stay in the cell

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Stages of Protein Synthesis

Back 19

1. Transcription

2. Translation

3. Proteins move to cisternae of RER and are packaged into vesicles

4. Vesicles move along the cytoskeleton to the Golgi apparatus

5. Vesicles fuse with the cis face of the Golgi and the proteins enter

6. The proteins are structurally modified such as adding carb groups etc.

7. Proteins leave the Golgi in vesicles pinched off at the trans face

8. Vesicles move towards and fuse to the cell surface membrane, releasing their contents by exocytosis. Or vesicles form lysosomes to remain in cell

Front 20

Transcription

Back 20

The copying of DNA base sequence in the nucleus using RNA, forming mRNA which leaves through the nuclear pores

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Translation

Back 21

Sequence of amino acids chained together at ribosomes to match mRNA triplet code

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Cellulose Cell Wall

Back 22

Rigid structure made of carbohydrate cellulose. Freely permeable. Contents of the cell push against the wall making it rigid. The wall acts as protection for the contented from invading pathogens

Front 23

Vacuoles

Back 23

Membrane lined sac in the cytoplasm containing cell sap. Most cells have large vacuoles to maintain rigor. Membrane is called tonoplast, it is selectively permeable.

Front 24

Chloroplasts

Back 24

Organelles responsible for photosynthesis. Double membrane bound structure similar to mitochondria. The fluid enclosed is called the stroma and they have an internal network of membranes called granum. Grana are joined by lanellae and the grana contain photosynthetic pigments

Front 25

Prokaryote/Eukaryote Comparison

Back 25

Front 26

Elements in Carbohydrates

Back 26

Carbon, Hydrogen and Oxygen

Front 27

Elements in Lipids

Back 27

Carbon, Hydrogen and Oxygen

Front 28

Elements in Proteins

Back 28

Carbon, Hydrogen, Oxygen, Nitrogen and Sulfur

Front 29

Elements in Nucleic Acids

Back 29

Carbon, Hydrogen, Oxygen, Nitrogen and Phosphorus

Front 30

Uses of Water and the properties which lead to them

Back 30

• Solvent - many solutes in an organism can be dissolved in water

• Coolant - High specific heat capacity

• Transport Medium - Capillary attraction, adhesive and cohesive

• Stable Environment for organisms - stable, doesn't change temperature or state easily

• Insulation - Floating ice keeps lower water warm so aquatic organisms survive at lower temperatures

Front 31

α Glucose - Structure

Back 31

Front 32

β Glucose - Structure

Back 32

Front 33

Glycosidic Bond

Back 33

Front 34

Cellulose Structure

Back 34

Alternating orientation of β Glucose. Cellulose form hydrogen bonds between each other forming microfibrils which form together to make fibres. This makes it strong and insoluble

Front 35

Monomers of Lactose

Back 35

Galactose and Glucose

Front 36

Starch

Back 36

Polymer of α Glucose

Bonds between C1 - C4

Twisted with hydrogen bond supports

Front 37

Amylopectin

Back 37

Branched molecule

Bonds between C1-C4 and C1-C6

Front 38

Glycogen

Back 38

Polymer of glucose

Branched, more than amylopectin so more compact

Branching leaves many glucose open to be removed

Front 39

Hydrolysis

Back 39

Reaction which breaks down polysaccharides with the addition g water

Front 40

Test for Reducing Sugars

Back 40

Benedict's Test for Reducing Sugars:

Place sample in boiling tube, grind and blend if necessary

Add equal volume of Benedict's Reagent (alkaline solution of Copper II Sulfate)

Heat mixture gently in boiling tube for 5mins

Results:

Blue>Green>Yellow>Orange>Red

No>High reducing sugars

Reducing sugars give up electrons to Cu2+ ions forming Cu+ hence colour change

Front 41

Test for Starch

Back 41

Iodine test for Starch:

Mix a few drops of potassium iodide solution with food sample

Results:

Positive when yellow/brown changes to purple/black

Front 42

Test for lipids

Back 42

Emulsion Test for Lipids:

Mix food sample with ethanol

Solution is then mixed with water and shaken

Results:

White Emulsion - Lipids Present

Remains Clear - No lipids

Front 43

Test for Protein

Back 43

Biuret Test for Proteins:

Add liquid sample to test tube

Add equal volume Biuret Reagent

Shake mixture and leave to stand for 5mins

Results:

Purple/Mauve - Proteins present

No change - Proteins not present

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Saturated

Back 44

No double bonds present between carbon atoms

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Unsaturated

Back 45

Double binds present between some carbon atoms

Front 46

Triglyceride

Back 46

One glycerol molecule combined with three fatty acids

Front 47

Phospholipids

Back 47

Modified triglycerides which contain phosphorus. The phosphate ions are negatively charged and so soluble in water

Front 48

Sterols

Back 48

Steroid alcohols, type of lipid found in cells

e.g cholesterol which regulates fluidity of phospholipid bilayer in membranes

Front 49

Roles of lipids

Back 49

• Membrane formation, creation of hydrophobic barriers

• Hormone Production

• Electrical insulation for nerve transmission

• Waterproofing

• Thermal insulation

• Protection/cushioning of vital organs

• Buoyancy

Front 50

Amino Acids Structure

Back 50

Front 51

Peptide Bond

Back 51

Front 52

Primary Level of Protein Structure

Back 52

Sequence of amino acids, influence how peptide folds and it's final shape

Only peptide bonds

Front 53

Secondary level of protein structure

Back 53

Oxygen, hydrogen and nitrogen interact

Hydrogen bonds form

H Bonds either pull together one chain into an α helix

Or, multiple chains to form a β pleated sheet

Front 54

Tertiary level of protein structure

Back 54

Folding of protein into final shape

Secondary structure brings R-groups close together to interact and fold

Interactions between R-groups may be:

- Hydrophobic/Hydrophilic interactions

- Hydrogen Bonds

- Ionic Bonds between +ve R-groups

- Disulfide bonds, covalent bonds between R-groups with sulfur

Front 55

Quaternary level of protein structure

Back 55

Association of two or more individual proteins called sub units

Interactions between sub units the same as tertiary but between peptide molecules

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Globular Proteins

Back 56

Compact and water soluble proteins

Roughly spherical in shape

Formed when tertiary structure keep Hydrophobic R-groups away from aqueous environment

Hydrophilic R-groups on outer side of protein

Front 57

Conjugated Proteins

Back 57

Globular Proteins with a prosthetic group, non protein component

Front 58

Haemoglobin

Back 58

Quaternary conjugated protein made of 4 polypeptides

Two α subunits, two β subunits.

Each containing a haem group, the iron II ion can combine with oxygen

Front 59

Catalase

Back 59

Quaternary conjugated protein with four haem groups allowing it to catalyse breakdown of hydrogen peroxide.

Front 60

Fibrous Proteins

Back 60

Long insoluble molecules, due to high proportion of hydrophobic R-Groups. Tend to make long, strong molecules.

Front 61

Keratin

Back 61

Fibrous protein with large proportion of sulfur and disulfide bonds. Found in hair

Front 62

Elastin

Back 62

Fibrous protein, elastic fibres in alveoli and blood vessels

Front 63

Collagen

Back 63

Fibrous protein, rope-like connective tissue found in skin and tendons

Front 64

Nucleotide

Back 64

Monomers of nucleic acids

Phosphodiester bonds form between nucleotides to produce nucleic acids

Front 65

DNA

Back 65

Deoxyribose Nucleic Acid

Contains Penrose sugar - deoxyribose

Two types of bases:

- Pyrimidines, smaller bases with single carbon ring. Thymine and Cytosine

- Purines, larger bases with double carbon ring. Adenine and Guanine

Double helix structure, two strands run antiparallel (5' one end 3' at the other) to each other joined by hydrogen bonds

A - T (2 hydrogen bonds)

C - G (3 hydrogen bonds)

Front 66

RNA

Back 66

Ribose Nucleic Acid

Ribose pentose sugar

Thymine base replaced with Uracil

U - A (2 hydrogen bonds)

Front 67

DNA Replication

Back 67

Front 68

Codon

Back 68

A triple of bases which code for a single amino acid

Front 69

ATP

Back 69

Adenosine Triphosphate

Universal energy currency

Not good as a long term energy store as phosphate bonds are unstable

Attaching Pi to an ADP creates ATP. This is phosphorylation.

ATP + H2O -> ADP + Pi + Energy

Properties:

- Small

- Water soluble

- Bonds between phosphates provide immediate energy

- Release energy in manageable small quantities, energy is not wasted as heat

- Easily regenerated

Front 70

Enzymes

Back 70

Globular proteins which catalyse biological reactions

Catalyse anabolic (building up) and catabolic (breaking down) reactions

Front 71

Lock and Key Hypothesis

Back 71

Active site on enzyme is complimentary to substrate, only specific substrates fit

Substrate and enzyme bind to form enzyme-substrate complex

Substrate(s) react and form enzyme-product complex

The product leaves and the enzyme is not used so continues to function

Front 72

Induced Fit Hypothesis

Back 72

Active site changes shape slightly as substrate enters

This puts strain on the substrates binds as a molecule

This lowers activation energy for the reaction

Front 73

Intracellular Enzymes

Back 73

Enzymes which act within cells e.g. catalase

Front 74

Extracellular Enzymes

Back 74

Enzymes that act outside of cells e.g. amylase and trypsin

Front 75

Digestion of Starch

Back 75

Starch is broken down to maltose via amylase produced in the salivary glands and pancreas

Maltose is broken down to glucose via maltase in the small intestine

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Digestion of proteins

Back 76

Trypsin, a protease, is produced in the pancreas and released in the pancreatic juice in the small intestine. It breaks down proteins into amino acids

Front 77

Competitive inhibition

Back 77

Molecule or part of a molecule with a similar shape to the substrate, fits in active site

Reduces rate of reaction but does not reduce Vmax

e.g. statins inhibit cholesterol synthesis so are prescribed to reduce cholesterol levels

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Non-competitive inhibition

Back 78

Molecule binds to other part of enzyme, an allosteric site

This alters the tertiary structure and the active site is no longer complimentary

Decreases rate of reaction and Vmax

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Cofactors

Back 79

A non-protein 'helper' component needed to carry out an enzymes function as a catalyst.

If it is an organic molecule it is a coenzyme

Front 80

Precursor Activation

Back 80

A change in the enzymes shape required to be activated. Can be achieved by the addition of a cofactor or another enzyme cleaving of certain bonds to open up the active site

Front 81

Intrinsic Proteins

Back 81

Proteins imbedded in both layers of the phospholipid bilayer

Channel proteins - allows passive movement

Carrier proteins, active and passive transport

Front 82

Glycoproteins

Back 82

Used for cell signalling, receptors for neurotransmitters and peptide hormones

Front 83

Glycolipids

Back 83

Cell markers or antigens so it can be recognised by the immune system

Front 84

Facilitated diffusion

Back 84

Diffusion across a membrane through protein channels

Front 85

Active Transport

Back 85

Movement of ions from low concentration to high concentration, requiring energy and a carrier protein

ATP bind to the carrier protein and is hydrolyse into ADP + Pi

shape

Molecule is released into the cell

Binding phosphate causes the protein to change shapeMolecule is released into the cellPhosphate is released and joins to ADP to form ATPProtein returns to original shape

Phosphate is released and joins to ADP to form ATP

Protein returns to original shape

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Bulk Transport

Back 86

Movement of large molecules such as enzymes or whole cells such as bacteria

Endocytosis (Phagocytosis - solids, pinocytosis - liquids), bulk transport into cells

Exocytosis, bulk transport out

Front 87

Osmosis

Back 87

Diffusion of water across a partially permeable membrane from high water potential to low water potential

Front 88

Cell Cycle

Back 88

Interphase - Normal cell activity:

Protein Synthesis

Mitochondria grow and divide

Chloroplasts grow and divide

Normal metabolic processes

G1 - First growth phase:

Proteins from which organelles are synthesised are produced and organelles replicate

Cell increases in size

CHECKPOINT - Cell size, nutrients, growth factors, DNA damage

S - Synthesis phase:

DNA is replicated in the nucleus

G2 - Second growth phase:

Cell increases in size

Replicated DNA is checked

Energy stores increase

CHECKPOINT - Cell size, DNA replication, DNA damage

Final CHECKPOINT - Spindle assembly, check chromosomes are attached to spindle