Module 2 (2/2) Flashcards
(69 cards)
1
Q
Example of intracellular and extracellular enzymes? (2)
A
- Intracellular = RNA polymerase (1)
- Extracellular = Amylase (1)
2
Q
What are the mechanisms of enzyme action? (2)
A
- Lock and key model (1)
- Induced fit model (1)
3
Q
Explain catalysis of lock and key model? (3)
A
- Substrate binds to active site perfectly to form an ES complex (1)
- Enzyme converts substrate into product, forming EP complex (1)
- Product is released from enzyme active site (1)
4
Q
Explain catalysis of induced fit model? (3)
A
- Substrate binds to active site to form ES complex (1)
- Enzyme undergoes conformational change to convert substrate
to product, forming EP complex (1) - Product is released from enzyme active site (1)
5
Q
Why is induced fit model the more widely accepted? (2)
A
- Conformational change explains how bonds break for product to
form (1) - Explains why enzymes like lipase have broader specificity (1)
6
Q
What happens when enzyme and substrate concentration increases? (2)
A
- More frequent collisions increases results in more ES complexes
formed (1) - Overtime graph plateaus as increased concentration becomes
limiting factor (1)
7
Q
What does it mean when saturation point is reached? (2)
A
- All enzyme active sites are occupied (1)
- Reaction is as fast as possible, known as Vmax (1)
8
Q
What happens to enzyme activity when temperature increases? (2)
A
- Temperature increases till optimum increases kinetic energy,
collisions and ES complex formation (1) - Too high temperature results in denaturing as tertiary structure
breaks down (1)
9
Q
What happens to enzyme concentration with pH change? (2)
A
- Optimum pH changes depending on enzyme (1)
- Concentrations of OH- and H+ will affect ionic and hydrogen
bonding and therefore tertiary structure (1)
10
Q
Whats Temperature Coefficient Q10 + Example (2)
A
- Indicates how much rate changes when temperature increases by
10°c - Q10 = rate of higher temp /
rate of lower temp - When Q10 is 2, the rate doubles every 10°c
11
Q
What are cofactors + example? (4)
A
- Non proteins molecules that need to be bound to an enzyme for it
to work (1) - Inorganic cofactors work by helping the enzyme bind to its
substrate (1) - Chemically unchanged (1)
- Magnesium ion is a cofactor for DNA polymerase (1)
12
Q
What are coenzymes + example? (4)
A
- Organic cofactors (1)
- Chemically altered (1)
- Carry chemical groups between enzymes (1)
- Derive from vitamins (1)
13
Q
Whats a prosthetic group + example? (2)
A
- Cofactor tightly bound to its enzyme (1)
- Iron containing heme group is the prosthetic group of haemoglobin
as a permanent part of its structure (1)
14
Q
What is competitive inhibition? (2)
A
- Binds with enzymes active site and compete with substrate
(1) - Effect can be reduced by increasing substrate concentration (1)
15
Q
What is non competitive inhibition? (2)
A
- Binds with allosteric site of enzyme and alters structure (1)
- Effect cannot be reduced (1)
16
Q
What are reversible and irreversible inhibitors? (2)
A
- Reversible are easily removed with weak hydrogen and ionic
bonding (1) - Irreversible are hard to remove with strong covalent bonds (1)
17
Q
Examples of enzyme inhibitor uses? (2)
A
- Drugs such as antibiotics (1)
- Metabolic poisons (1)
18
Q
What is end product inhibition? (3)
A
- When the product produced by metabolic pathway inhibits an
enzyme that was used before (1) - Controls the amount of product produced (1)
- Reversible so enzyme can function again if product decreases (1)
19
Q
What are the functions of the plasma membrane? (3)
A
- Partially permeable barrier (1)
- Cell recognition (1)
- Cell communication (1)
20
Q
What are the functions of intracellular membrane? (3)
A
- Forms vesicles to transport substances (1)
- Site of chemical reactions (1)
- Compartmentalises the cell (1)
21
Q
What is meant by the fluid mosaic model? (2)
A
- Fluid as phospholipids are constantly moving around (1)
- Mosaic refers to the protein molecules scattered throughout the
phospholipids (1)
22
Q
What are the components of the plasma membrane? (5)
A
- Phospholipids (1)
- Glycoproteins (1)
- Glycolipids (1)
- Cholesterol (1)
- Intrinsic/Extrinsic Proteins (1)
23
Q
What are Glycoproteins/Glycolipids? (3)
A
- Proteins/Phospholipids with a sugar molecule attached (1)
- Both act as cell recognition sites and antigens (1)
- Glycolipids increase membrane stability by forming hydrogen bonds
with water molecules (1)
24
Q
What is cholesterol? (2)
A
- A lipid that slots between phospholipid tails and pushes them
together (1) - Stabilises membrane and make it more rigid (1)
25
What are intrinsic and extrinsic proteins? (4)
- Intrinsic found across both bilayers (1)
- Act as channel and carrier proteins to transport water soluble
molecules (1)
- Extrinsic found on surface of plasma membrane (1)
- Function as enzymes and catalyse chemical reactions in the cell (1)
26
How do you investigate cell membrane permeability? (4)
- Make similar cutting of the same beetroot and rinse to remove
excess pigments (1)
- Put each beetroot in a test tube and in varying water baths (1)
- Pour test tube liquid into cuvettes and put into colorimeter (1)
- The higher the permeability, the darker the pigment and therefore
more light absorbed (1)
27
What are phospholipids? (3)
- One hydrophilic head group (1)
- Two hydrophobic tails (1)
- Barrier to anything not lipid soluble (Ions/Glucose) (1)
28
What happens to membrane permeability as temperature increases? (3)
- At below 0°C, permeability is high with proteins deformed and at
-50°C, ice crystals form, puncturing membrane and increasing
permeability further (1)
- From 0°C - 45°C the membrane is semi-permeable with fluidity
increasing as kinetic energy does (1)
- After 45°C, permeability increases rapidly as proteins denature and
water in cytoplasm expands creating pressure gaps (1)
29
What happens to membrane permeability as ethanol concentration increases? (3)
- Membrane permeability and ethanol concentration are directly
proportional (1)
- Ethanol will dissolve non-polar lipids (1)
- Very high ethanol concentration will kill the cell as plasma
membrane disintegrates (1)
30
How are molecules transported across plasma membrane? (2)
- Osmosis/Diffusion/Active transport (1)
- Larger molecules such as proteins and carbohydrates rely on
endocytosis and exocytosis (1)
31
What is Simple Diffusion + Example? (2)
- Diffusion of non polar molecules directly through the phospholipid
bilayer (1)
- E.G. CO2 and O2 during gas exchange (1)
32
What does the rate of simple diffusion/osmosis depend on? (3)
- Thickness of exchange surface (1)
- Concentration gradient steepness (1)
- S.A such as microvilli (1)
33
How do you investigate simple diffusion? (2)
- Phenolphthalein agar jelly and sodium hydroxide added with
hydrochloric acid (1)
- Diffusion will cause jelly to go pink to colourless (1)
34
What is Facilitated Diffusion + Example? (2)
- Diffusion of polar molecules across channel or carrier proteins (1)
- E.G. Glucose molecules into liver cells (1)
35
What does the rate of facilitated diffusion depend on? (2)
- Number of carrier or channel proteins (1)
- Concentration gradient steepness (1)
36
What is osmosis? (2)
- Movement of water down a water potential gradient across a semi
permeable membrane (1)
- High water potential to low water potential (1)
37
What is meant by isotonic and pure water? (2)
- Pure water has the highest water potential (1)
- Isotonic means water potential is the same (1)
38
What is meant by hypertonic and hypotonic solution? (2)
- Hypertonic has high solute concentration and lower water potential
(1)
- Hypotonic has a low solute concentration and higher water
potential (1)
39
What happens to animal cells in hypertonic and hypotonic solution? (2)
- Animal cell will shrink in hypertonic solution (1)
- Animal cell will burst in hypotonic solution as it can't handle turgor
pressure (1)
40
What happens to plant cells in hypertonic solution? (2)
- Plant becomes flaccid with shrunk vacuole (1)
- Cell membrane pulls away from cell wall known as plasmolysis (1)
41
What happens to plant cells in hypotonic solution? (2)
- Plant becomes turgid with swollen vacuole (1)
- Cytoplasm pushes against cell wall as it withstands turgid pressure
to not burst (1)
42
How do you determine water potential of potato cells? (2)
- Add potato cuttings into serial dilutions of the sucrose solutions
with the same water volume (1)
- Water potential is where the solution and cytoplasm is isotonic with
no mass change (1)
43
What is active transport? (2)
- Transfer of polar molecules across carrier proteins (1)
- E.G. Glucose from intestine villi to bloodstream (1)
44
What does the rate of active transport depend on? (2)
- Number of carrier proteins (1)
- Rate of respiration (1)
45
What are cotransporters? (2)
- Type of carrier proteins (1)
- Transports two different molecules simultaneously (1)
46
What is endocytosis? (3)
- When entering molecules are too large to cross plasma membrane
(1)
- Membrane folds the membrane and pinches off to form a vesicle (1)
- Active process (1)
47
What is exocytosis? (3)
- When large molecules (E.G. hormones and enzymes) need to leave
the plasma membrane (1)
- Vesicles containing molecules fuse with plasma membrane to be
released out the cell (1)
- Active process (1)
48
What does mitosis produce? (1)
- Two identical daughter cells (1)
49
What is the cell cycle made up of? (4)
Interphase:
- Gap phase 1 (G1) (1)
- Synthesis phase (1)
- Gap phase 2 (G2) (1)
- Mitosis (1)
50
What are the growth phases of interphase? (3)
- Gap phase 1 = Organelles replicate with lots of protein synthesis (1)
- Synthesis phase = DNA replicates (1)
- Gap phase 2 = Growth until organelles duplicate (1)
51
Where are the checkpoints of the cell cycle? (2)
- Before and after the Synthesis (S) phase (1)
- Check DNA to minimise mutation replication (1)
52
What happens during prophase? (3)
- Chromosomes condense (1)
- Nuclear envelope disintegrates (1)
- Centrioles opposite poles of the cell (1)
53
What happens during metaphase? (2)
- Chromosomes line up in middle of the cell (1)
- Chromosomes centromeres connected to spindle fibres (1)
54
Whats the structure of chromosomes after DNA is duplicated before mitosis? (2)
- 2 sister chromatids (1)
- Connected by centromere (1)
55
What happens during anaphase? (2)
- Centromere splits (1)
- Chromatids pulled to opposite ends of the cell (1)
56
What happens during telophase? (2)
- 2 pairs of chromosomes decondense (1)
- Nuclear envelope is reformed forming 2 nuclei (1)
57
What happens during cytokinesis of mitosis? (2)
- Cytoplasm divides and plasma membrane pinches off (1)
- Two identical daughter cells formed (1)
58
How do you investigate mitosis? (2)
- Staining chromosomes on root tip cells (1)
- Contains meristem tissue which is where mitosis in plants take place (1)
59
What are gametes? (3)
- Sex cells (Egg/Sperm) (1)
- Haploid contains half chromosomes (1)
- Fertilised egg forms a zygote with all chromosomes (1)
60
What is meiosis? (2)
- Production of 4 genetically different gametes (1)
- Two rounds of splitting with meiosis I and meiosis II (1)
61
How does meiosis increase genetic variation? (2)
- Crossing over (1)
- Independent assortment (1)
62
How does crossing over work? (2)
- In prophase I, homologous chromosomes exchange genetic material (1)
- Chromosomes will have different combinations of alleles (1)
63
How does independent assortment work? (2)
- Order of chromosome lineup along equator during metaphase I (1)
- Array of combinations of chromosomes at each gamete (1)
64
What are stem cells? (3)
- Unspecialised cells (1)
- Specialised through cell differentiation (1)
- Potency refers to the ability the stem cell differentiates (1)
65
What are all the potencies? (4)
Totipotent = Divide to any type of cell (1)
Pluripotent = Divide into any except embryonic cells (1)
Multipotent = Divide into a few types of cells (1)
Unipotent = Divide into one type of cell (1)
66
What are examples of potency? (4)
Totipotent = Zygote (1)
Pluripotent = Meristem tissue (1)
Multipotent = Bone marrow (1)
Unipotent = Epidermal stem cells (1)
67
How are stem cells used in medicine? (2)
- Stem cell transplants to replace stem cells broken by infection (Bone Marrow) (1)
- Research for stem cells to differentiate into whole organs to reduce donation wait (1)
68
How is the leaf an example of an organ? (2)
- Collection of tissues to perform a specific function of photosynthesis (1)
- Upper epidermis and spongy mesophyll (1)
69
How is the lung an example of an organ? (2)
- Collection of tissues to perform a specific function of transferring O2 and CO2 (1)
- Endothelium and squamous epithelial tissue (1)
