3.2 Cells Wrong Answers

Question 1

define resolution

Answer 1

the minimum distance apart that 2 objects can be in order for them to appear as separate items

Question 2

examples of carbohydrates absorbed across membrane in small intestine

Answer 2

glucose, galactose and fructose

Question 3

two things which break down in prophase

Answer 3

nuclear envelope breaks down, nucleolus disappears

Question 4

3 main stages of the cell cycle

Answer 4

interphase, nuclear division, cell division/cyotkinesis

Question 5

a feature to support transport across membranes

Answer 5

presence of mitochondria to provide ATP needed for active transport by aerobic respiration

Question 6

differences between FD and AT

Answer 6

FD only occurs at channels of the protein
AT only uses carrier proteins where FD also uses channel proteins

Question 7

why dry potato tissue before weighing in osmosis practical

Answer 7

to ensure the amount of water on all cylinders is the same as the surface water volume will otherwise vary

Question 8

why is percentage change a better value to use than the raw numbers

Answer 8

it allows an easier comparison because samples may have different start and end weights

Question 9

unthought of method of transport across membranes

Answer 9

by phagocytosis/endocytosis, the molecule is engulfed by the cell surface membrane to form a vesicle/vacuole

Question 10

bacterium cell wall

Answer 10

made of murein, makes cell wall rigid so cannot change shape

Question 11

define antigen

Answer 11

a specific protein on the surface of a cell which triggers an immune response and the production of antibodies

Question 12

similarities of b and t cells

Answer 12

both made from stem cells and are types of wbc

Question 13

differences of b and t cells

Answer 13

t mature in thymus where b mature in the bone marrow, t associated with cell mediated and b associated with humoral

Question 14

organelles useful in a B cell

Answer 14

mitochondria for energy release from ATP by aerobic respiration for massive antibody production
golgi apparatus to package the antibodies and process them
rough endoplasmic reticulum to synthesise and transport the proteins

Question 15

compare cell mediated to humoral

Answer 15

cm involves t cells and phagocytes, effective through cells. humoral involves b cells and antibodies, effective through bodily fluids

Question 16

distinguish between active and passive immunity

Answer 16

active involves the individual’s production of antibodies by their own immune system after being exposed to the pathogen, and is usually long lasting. passive involves introduction of already produced antibodies to the individual’s immune system, is usually short lived.

Question 17

why are vaccinations given more than once

Answer 17

more exposure to antigen, more memory cells produced, so antibodies will be made quicker if infected

Question 18

why may a vaccine be ineffective if HIV quickly enters host cell

Answer 18

antibody does not locate HIV before it enters host cell, once inside the antibody cannot reach/destroy it

Question 19

HIV replication

Answer 19

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

Question 20

cells that trigger immune response

Answer 20

tumour cells, cells from other organisms, foreign cells

Question 21

monoclonal antibody

Answer 21

antibody produced from a cloned plasma cell

Question 22

how does phagocytosis lead to presentation of antigens

Answer 22

phagocyte engulfs virus in a phagosome. lysosomes fuse with phagosome and release lysozymes which hydrolyse the cell wall of the virus. antigens are then presented on the cell surface membrane.

Question 23

antibody

Answer 23

a protein specific to an antigen secreted by plasma cells

Question 24

environmental variables which impact cell growth rate

Answer 24

increase in oxygen, increased resp
inc in temp, inc in enzyme activity
inc phosphates inc in DNA/ATP/RNA
inc ncts = inc DNA synthesis

Question 25

bacteria cell wall

Answer 25

peptidoglycan

Question 26

explain features of prophase

Answer 26

chromosomes are visible because they are still condensing. they are randomly arranged bcs there is no spindle formed yet

Question 27

homologous pair

Answer 27

a pair of chromosomes with the same genes

Question 28

sterilisation techniques

Answer 28

lid on PD to prevent any unwanted microorganisms contaminating the dish
wear gloves to prevent contam from hands
flame loop to maintain a pure culture of bacteria

Question 29

identifiable of anaphase

Answer 29

if a v shape is visible, it shows sister chromatids have been pulled apart