Cells

Question 1

What is a eukaryote?

Answer 1

A cell that contains a nucleus

Question 2

What is a prokaryote?

Answer 2

Cells that do not have a nucleus , e.g. Bacteria, red blood cells

Question 3

What is contained in a nucleus?

Answer 3

DNA and chromatin (associated proteins found in the cell)

Question 4

What is the name of double membrane of the nucleus ?

Answer 4

Nuclear envelope

Question 5

What is the name of the small holes found in the double membrane and what do they do?

Answer 5

Nuclear pores- these allow proteins to diffuse in and mRNA to diffuse out

Question 6

What is the dense structure within the nucleus called and what does it do?

Answer 6

Nucleolus- the ribosomes are made here

Question 7

What does respiration do?

Answer 7

Respiration produces ATP

Question 8

What is the name of the structures formed by inner membrane of the mitochondria?

Answer 8

Cristae- this increases the surface area so it allows for more room for enzymes that are involved in respiration

Question 9

What is found in the inside the double membrane and what does it do?

Answer 9

Matrix- this contains enzymes which are involved in respiration

Question 10

What is the rough endoplasmic reticulum? (r-ER)

Answer 10

It is a bag of membrane which has ribosomes on the outside and it’s involved in protein synthesis (folding and processing of proteins)

Question 11

What is the smooth endoplasmic reticulum?

Answer 11

It is a bag of membrane involved in the processing and modification of lipids

Question 12

What is the function of Golgi apparatus?

Answer 12

it forms lysosomes and it modifies proteins and lipids that were produced by the r-ER

Question 13

What are the function of vesicles?

Answer 13

membrane bound pacakges of proteins/lipids which can move in between organelles

Question 14

function of lysosomes

Answer 14

contains digestive enzymes (lysozomes) which to break down old redundant organelles in the cell

Question 15

why does high mutation rate make it difficult to develop a vaccine

Answer 15

mutation will cause antigenic variability
vaccines contain specific antigen
antibodies that are produced would not be complimentary to change antigen

Question 16

How does a vaccine work?

Answer 16

Vaccine contains an antigen
Antigen is presented on antigen presenting cell
This causes specific T helper cell to bind to antigen on the B cell and STIMULATES THE CELL
This leads to B cell clonal selection to produce plasma cells
Plasma cells produce antibodies

Question 17

difference between prokaryotic cell DNA and eukaryotic cell DNA

Answer 17

eukaryotic DNA associated with histones, prokaryotic DNA isn’t
eukaryotic DNA is linear, prokaryotic DNA is short and circular

Question 18

what are monoclonal antibodies?

Answer 18

antibodies produced from single clone of B cells

Question 19

features of a successful vaccine program

Answer 19

Produces few side effects
Must be economically viable
Must have trained personnel to administer the vaccine
Must have means of transporting the vaccine

Question 20

Define herd immunity

Answer 20

Where most of the population is vaccinated to protect those who aren’t vaccinated
Unlikely that two unvaccinated people are in contact with each other

Question 21

How HIV replicates

Answer 21

HIV capsule fuses with cell membrane of T Helper Cell
HIV release viral enzymes + viral RNA into host cell
Reverse transcriptase convert RNA to DNA
Viral mRNA can be transcribed and produce viral proteins and viral particles

Question 22

Define active immunity

Answer 22

When body is stimulated to produce their own antibodies

Memory cells are produced

Question 23

Define passive immunity

Answer 23

Antibodies are entered into the body

No memory cells are produced so no long lasting immunity

Question 24

Describe the process of phagocytosis

Answer 24

Phagocytes are attracted to pathogen due to chemical (attractants)
The phagocyte engulfs the pathogen and pathogen is engulfed in a vesicle called a phagosome
Lysosomes fuse with the phagosome and release hydrolytic enzymes called lysozomes which hydrolyse the phagosome

Question 25

Advantage of using a TEM microscope

Answer 25

Higher resolution

Can see internal details

Question 26

Advantage of SEM microscope

Answer 26

Can see 3D images

Can use thicker specimens

Question 27

principles of using a TEM microscope

Answer 27

electrons pass through the specimen and the denser parts of the specimen absorb more electrons and they therefore appear darker
electrons have a shorter wavelength than light so can you have a higher resolution

Question 28

disadvantages of using a TEM microscope

Answer 28

specimen has to be thin
specimen has to be dead- placed in vacuum
staining process is complex and the stains are usually toxic
artefacts are present
image only produced in 2D

Question 29

Role of ribosome in production of polypeptide

Answer 29

mRNA binds at ribosome and forms two sites
tRNA has anticodons
Catalysed formation of peptide bonds between amino acids
Ribosome moves along mRNA