AOS 1

Question 1

What are 5 pieces of evidence supporting the bacterial origins of chloroplasts and mitochondria?

Answer 1

1. They have their own DNA, which is circular.
2. They have their own ribosomes and produce their own proteins.
3. They reproduce by binary fission independently of cell cycle.
4. They are bound by a double plasma-membrane.
5. They have porin transport proteins only found in prokaryotic plasma membranes.

Question 2

How are glucose/carbohydrates stored in plant cells? (2)

Answer 2

As starch in plant cell amyloplasts.

As cellulose in plant cell wall.

Question 3

How are glucose/carbohydrates stored in animal cells?

Answer 3

As glycogen in liver and muscle cells.

Question 4

What bonds join amino acids, what reaction, what molecule is produced?

Answer 4

Peptide bonds join amino acids in a condensation reaction (produces water molecule) which produces a polypeptide (protein).

Question 5

Describe the amino acid structure.

Answer 5

Amino group (H2N), Carbon atom, Carboxyl group (COOH), Hydrogen atom, R chain

Question 6

Describe the four protein orders and bonds.

Answer 6

Primary: linear sequence of amino acids (peptide bonds).
Secondary: folding to alpha-helix or beta-pleated (hydrogen bond).
Tertiary: irregular folding (hydrogen and ionic bonds).
Quaternary: 2 or more tertiary chains.

Question 7

List 5 factors that affect diffusion

Answer 7

Size of molecule, polarity, charge, amount, concentration gradient.

Question 8

List 5 functions of the plasma membrane

Answer 8

Protects cell
Contains contents
Cell identity
Communication
Controls movement of substances

Question 9

Describe the structure of a phospholipid

Answer 9

Polar head: glycerol backbone & phosphate group

Non-polar tails: 2x fatty acid chains (one sat, one un-sat)

Question 10

Identify RNA/DNA in a nucleotide

Answer 10

(bottom of pentagon)
2x OH groups = RNA
1x OH 1x H = DNA

Question 11

What is the difference between the two types of inhibitors?

Answer 11

Competitive: competes for active site

Non-competitive: alters active site shape

Question 12

What is a coenzyme?

Answer 12

An organic (molecule) that allows enzyme to function, usually by carrying an electron/ion (eg. ATP/NADPH).

Question 13

What is a cofactor?

Answer 13

Inorganic (ion) that allows enzyme to function.

Question 14

What is activation energy?

Answer 14

The energy required to break the bonds in the reactants of a reaction so the reaction can begin.

Question 15

How do enzymes affect activation energy?

Answer 15

They lower Ea

Question 16

Describe a condensation reaction

Answer 16

A reaction that releases water molecules (eg. polymerisation, anabolic (absorbs energy) (THINK PHOTOSYNTHESIS)

Question 17

Describe a hydrolysis reaction

Answer 17

Reaction that requires water, catabolic (releases energy) (THINK CELLULAR RESPIRATION)

Question 18

Describe the overall equation for photosynthesis

Answer 18

CO2 + H2O -> (Chlorophyll & light) O2 & C6H12O6

Question 19

Describe the first stage of photosynthesis

Answer 19

Light dependent
In thylakoid membrane of chloroplast
Chlorophyll absorbs light energy (enzymes)
H2O is split by light into H+ and O2, forms ATP
H+ joins to NADPH
Oxygen is waste product

Question 20

Describe the second stage of photosynthesis

Answer 20

Light independent/Calvin cycle
In stroma of chloroplast (liquid)
NADPH and ATP and CO2 are joined together by RuBisCo to form glucose

Question 21

What is the point where the rate of ps and res are equal?

Answer 21

Compensation point (no net increase/decrease of CO2)

Question 22

Describe the first stage of respiration

Answer 22

Glycolysis
In cytoplasm
Anaerobic
glucose split into pyruvate and 2ATP and 2NADH

Question 23

How much ATP is produced from respiration

Answer 23

36 or 38

Question 24

Describe the second stage of respiration

Answer 24

Krebs cycle
In matrix of mitochondria (fluid)
Pyruvate is oxidised to Acetyl CoA
Acetyl CoA is split into 6CO2, 2ATP, 6NADH, 2FADH2