Cells And Enzymes

Question 1

Conditions for cell fractionation

Answer 1

-ice cold stops digestive enzyme activity prevents organelles from being digested
-isotonic solution maintains constant water potential prevents organelles from shrivelling/bursting
-buffer solution maintains pH prevents proteins from denaturing

Question 2

Gene

Answer 2

Short section of DNA that contains a sequence of bases codes for AA sequence of a protein

Question 3

Virus replication

Answer 3

Attachment proteins attach to receptors on helper T cell/lymphocyte;
2. Nucleic acid/RNA enters cell;
3. Reverse transcriptase converts RNA to DNA;
4. Viral protein/capsid/enzymes produced;
5. Virus (particles) assembled and released (from cell);

Question 4

Binary fission

Answer 4

-circular DNA replicated once plasmids replicated many times cell gets bigger
-cytoplasm and CM divide new cell wall forms around new cells
-2 daughter cells made each contain one copy of circular DNA and variable number of plasmids
-daughter cells seperate

Question 5

Induced fit

Answer 5

Enzyme active site moulds around substrate to form enzyme substrate complex
Put pressure on bonds of substrate
Lowering activation

Question 6

How Ph affects rate of reaction

Answer 6

Ph= Chemical disruption, loss of 3D structure due to bonds breaking
Active site denatures so not complementary so fewer ESC

Question 7

Describe roles of iron, sodium and phosphate ions in cells

Answer 7

Irons ions:
Haemoglobin binds to oxygen
Sodium ions:
Co-transport of glucose/AA
Phosphate ions:
Affects osmosis
Joins nucleotides used to produce ATP
phosphorylates other compounds making them more reactive
Hydrophilic soluble part of PL bilayer

Question 8

Calculation for magnification

Answer 8

Magnification = image size/ Actual size

Question 9

Function of atp hydrolase

Answer 9

ATP> ADP+ Pi
Releases energy

Question 10

Structure and function of the nucleus

Answer 10

-nuclear envelope and pores holds genetic material
-chromosomes for DNA replication
-nucleolus production of ribosomes

Question 11

Structure of chloroplasts vs mitochondria

Answer 11

-both have double membrane
-both have 70s ribosomes
-both
-matrix in mitochondria vs stroma in chloroplast
-chloroplast has starch grains
-chloroplast has chlorophyll pigments mitochondria doesn’t
-chloroplast has thylakoid mitochondria has cristea

Question 12

Antibiotic reduce bacterial reproduction by

Answer 12

-inhibiting cell wall synthesis
-inhibiting DNA replication
-inhibiting protein synthesis

Question 13

Structure of mitochondria

Answer 13

-double membrane to increase surface area for enzymes in respiration
-matrix contains enzymes for kreb cycle
-large surface area to maximise atp production

Question 14

Structure of chloroplast

Answer 14

-chloroplast she’s double membrane which controls movement of substances
-granum large SA for LDR
-thylakoid fountain chlorophyll pigment to absorb light energy
-strong contains enzymes for LDR

Question 15

Mitosis

Answer 15

Prophase:
Chromosomes condense and become visible spindle forms from centrioles
Nuclear envelope splits
Metaphase:
Chromosomes line up at the equator
Spindle fibres attach to the centromeres of chromosomes
Anaphase:
Spindle fibres contract pulling sisters chromatids apart to opposite poles of the cell
Telophase:
Chromatids reach the poles and relax
Nuclear envelope reforms around each set of chromosomes