Biology CT4

Question 1

define capsid

Answer 1

the outside of a virus

Question 2

define lysis

Answer 2

breakdown of the cell

Question 3

define bacterial lawn plate

Answer 3

a plate containing nutrients to enable the bacteria to grow

Question 4

define nutrient agar

Answer 4

a thick layer of gel on which the bacteria grow

Question 5

what is a virus

Answer 5

it contains one or more strands of genetic material surrounded by a protein coat, or capsid, although may have additional layers surrounding the capsid

Question 6

What happens during the lytic cycle of a virus

Answer 6

-virus attaches to cell and injects genetic material
-viral genetic material forms a circle
-new viral genetic material and proteins are produced and assembled
-host cell lyses and viruses are released
-they attach to host and inject dna

Question 7

what happens during the lysogenic cycle of a virus

Answer 7

-viral genetic material inserts itself into the bacterial chromosome
-bacterium reproduces normally, replicating viral genetic material at each cell division
-cell and viral genetic material may reproduce many times

Question 8

how to work out the cross-sectional area of the zone of inhibition?

Answer 8

⊼r2

Question 9

why do we use antibioticts_

Answer 9

to treat bacterial infenctions

Question 10

where does the antibiotic go_

Answer 10

travels in the blood plasma

Question 11

how to antibiotics work_

Answer 11

destroy cell wall - prevent DNA replication

Question 12

what doe antibiotics do?

Answer 12

look for an antigen of bacteria

Question 13

define antibiotics?

Answer 13

they are substances that either kill bacteria or inhibit their cell processes

Question 14

what does pre-clinical stage mean_

Answer 14

the stage of testing for the making of an antibiotic

Question 15

define antiseptics

Answer 15

substances used to kill microorganisms on the surface of the body or equipment

Question 16

STAGE 1: what do you do in the core practical of antibiotics?

Answer 16

-use aseptic technique to pour an agar plate.
-when agar is set take a sterile pipette.
-take the bacterial culture and pass the neck of it through a Bunsen flame. insert the pipette into the culture and draw it up.
-pass it through the flame again and set it aside
-lift the lid of petri dish and add drops of culture to the agar. place the pipette in disinfectant
spread the culture across the agar with a sterile spreader
-

Question 17

STAGE 2: what do you do in the core practical of antibiotics?

Answer 17

• label the sections of the petri dish for each antibiotic.
  -sterilise the forceps and use them to place a filter paper disc on the control
  -re-sterilise them and place the other antibiotics
  -tape the lid of the dish on each side and put it in incubation

Question 18

define antibodies

Answer 18

a protein produced by lymphocytes in response to a specific antigen. they work within the immune system to destroy pathogens that entered the body

Question 19

define monoclonal antibodies

Answer 19

an antibody that has been cloned by identical immune cells

Question 20

how to make monoclonal antibodies?

Answer 20

• a particular antigen is injected into a mouse. the mouse then produces lymphocytes that make antibodies.
  -cancer cells are grown in a culture medium
  -the lymphocyte cell from the mouse and the cancer cell are fused together to make a hybridoma cell

Question 21

define hybridoma cells

Answer 21

they can both divide and make antibodies against the injected antigen

Question 22

what are the uses for monoclonal antibodies?

Answer 22

-identify a pathogen
-made to stick to specific cells in the body such as cancer or platelets
-medical diagnosis. made to be slightly radioactive

Question 23

define platelets

Answer 23

fragments of blood cells that can for blood clots

Question 24

what is the name of the hormone that is found in the urine of pregnant women?

Answer 24

HCG’ Human Chorionic Ganadotropin

Question 25

which zone does the urine pass through in a pregnancy test?

Answer 25

reaction zone --- control zone

Question 26

where does the HCG hormone bind in a pregnancy test?

Answer 26

to the antibody in the reaction zone

Question 27

where do the mobile antibodies that are attached to HCG bind in a pregnancy test?

Answer 27

results window

Question 28

what do antibodies that are not attached to HCG do in a pregnancy test?

Answer 28

move to control zone

Question 29

what would a woman see on her test if she was pregnant?

Answer 29

a blue line in the results window and control line

Question 30

what is the word equation for photosynthesis_

Answer 30

carbon dioxide + water = glucose + oxygen

Question 31

what is the role of the waxy cuticle

Answer 31

to help water fall off leaves

Question 32

what is the role of the palisade cells

Answer 32

they allow the leaf to absorb light

Question 33

what is the role of the spongy mesophyll

Answer 33

it creates air space to allow gas exchange

Question 34

what is the role of the stomata / guard cells

Answer 34

stomata-allows carbon dioxide to diffuse into the leaf guard cells-open or close the stomata

Question 35

what is the role of the xylem/phloem

Answer 35

the water travels to the leaf by xylem. glucose leaves the plant by phloem

Question 36

why is photosynthesis slower higher up?

Answer 36

there are fewer molecules of air per each cm3 the higher up a mountain you go

Question 37

what are the 3 limiting factors of photosynthesis

Answer 37

-temperature -amount of carbon dioxide -light

Question 38

how to do the core practical: Light intensity and photosynthesis

Answer 38

-get clear glass bottles and add 20 algal balls to each -and same amount of indicator to each bottle and place on their caps -set up a glass of water between the lamp and bottles -place each bottle at the same distance away from each other -with one of them cover it in tin foil and place it next to the one closest to the lamp -turn on the lamp and wait to see the obvious changes

Question 39

what are the root hair cells

Answer 39

the outer surfaces of many roots. they are provide a large surface area so that water and mineral ions can be quickly absorbed.

Question 40

what is the water absorbed by plant roots used for?

Answer 40

-carrying dissolved mineral ions -keeping cells rigid -cooling the leaves -photosynthesis

Question 41

what is diffusion

Answer 41

when particles constantly move in random directions and so particles in a fluid spread down a concentration gradient

Question 42

where does diffusion occur in a plant

Answer 42

inside the roots, the cell walls have an open structure allowing water particles to diffuse towards the middle of the root

Question 43

what is osmosis

Answer 43

when solvent molecules diffuse through a semi-permeable membrane from an area of high concentration to an area of low

Question 44

where does osmosis occur in a plant

Answer 44

water enters via the root hair cell as the cell membranes are semi-permeable and so water passes into the cytoplasm

Question 45

what is active transport

Answer 45

when mineral salts are pumped into the cell by the proteins in the cell membrane