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AQA A level biology <33 > November mock prep- topic 2 > Flashcards

November mock prep- topic 2 Flashcards

1
Q

what kind of image does a transmission EM produce?

A

photomicrograph

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2
Q

name the main difference between the samples needed when using electron microscopes

A

scanning electron microscopes do not need thin samples

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3
Q

what are viruses?

A

acellular(no cell structure)
akaryotes(non living)

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4
Q

describe the structure of viruses

A

capsid
attachment proteins
genetic material

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5
Q

what surrounds prokaryotic cells?

A

capsule

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6
Q

what are the functions of vacuoles?

A

acts as a food store
structural support for herbaceous plants

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7
Q

function of nucleolus

A

assembles ribosomes

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8
Q

function of rough endoplasmic reticulum

A

synthesis of proteins and glycoproteins

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9
Q

structure and function of mitochondria

A

matrix-contains proteins, lipids, ribosomes and DNA

cristae-attachment of enzymes and proteins

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10
Q

function of lysosomes

A

autolysis
release enzymes
digest worn out organelles

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11
Q

function of smooth endoplasmic reticulum

A

transportation and synthesis of lipids and carbohydrates

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12
Q

function of the golgi apparatus

A

modifies lipids and proteins

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13
Q

what happens during interphase?

A

DNA replicates
chromosomes visible

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14
Q

what happens during prophase?

A

nuclear envelope disintegrates
nucleolus disappears

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15
Q

what happens during metaphase?

A

spindle fibres form
chromosomes line up

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16
Q

what happens during anaphase?

A

chromosomes pulled to opposite poles
spindle fibres contract

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17
Q

what happens during telophase?

A

cytoplasm and cell membrane splits
spindles disintegrate
nucleolus and nuclear envelope reform

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18
Q

explain the process of virus replication

A

attaches to host cell via attachment proteins

nucleic acid injected which provides instructions to create viral components, nucleic acid etc.

new virus is assembled

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19
Q

what type of molecules can pass through the phospholipid bilayer?

A

lipid-soluble molecules

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20
Q

what are the functions of proteins in the phospholipid bilayer?

A

mechanical support
receptors

21
Q

what type of molecules are involved in facilitated diffusion?

A

large, polar molecules

22
Q

what factors affect facilitated diffusion?

A

concentration gradient
number of carrier or channel proteins

23
Q

what is water potential?

A

pressure created by water molecules

24
Q

how do plant cells appear in isotonic solutions?

A

flaccid

25
Q

how do animal cells appear in hypotonic solutions?

A

lysed

26
Q

how do plant cells appear in hypotonic solutions?

A

turgid

27
Q

what happens to the vacuoles in plant cells in hypertonic solutions?

A

shrink

28
Q

what type of proteins are used in active transport?

A

carrier proteins

29
Q

how does co transport work?

A

ATP undergoes a condensation reaction which releases energy

binds to the carrier protein which changes shape releasing the molecule on the other side

phosphate is released meaning shape returns to normal

phosphate recombines with ADP

30
Q

what are pathogens?

A

organisms that cause disease

31
Q

what are antibodies?

A

proteins that detect antigens

32
Q

what happens during inflammation?

A

histamine released from histamine granules
this leads to vasodilation which makes the area appear red

swelling caused by plasma leaks

33
Q

describe the similarities and differences between the two types of phagocytes

A

both made in bone marrow

macrophages-
larger
specific defences

neutrophils-
short life span
apoptosis
lots made

34
Q

what are antigens?

A

chemical markers on the outside of pathogens with a unique shape

35
Q

what are APCs?

A

antigen presenting cells- antigens presented on outer membrane of a phagocyte after pathogen digested

36
Q

describe the similarities and differences between the two types of lymphocytes

A

white blood cells found in the lymph nodes and blood

T lymphocytes-
made in bone marrow
produce antibodies

B lymphocytes-
made in thymus
directly affect cells

37
Q

what type of immunity does a specific response lead to?

A

long term immunity

38
Q

how does cell mediated immunity work?

A

antigens presented on outer surface (APC)

receptors on helper T cell fit onto antigens which activates the T cell to rapidly divide by mitosis

they either develop into memory T cells, activate cytotoxic T cells or simulate B cells to secrete antibodies

39
Q

how does the humoral response work?

A

B cells receive antigens

B cells process it and present it

helper T cell binds and activates B cells which then divide by mitosis to clone plasma and memory cells

plasma cells secrete antibodies that attach and destroy pathogens

40
Q

how do antibodies work?

A

agglutination- microbes dump together making it easier for the phagocyte

neutralising toxins- bind to toxins

present viruses entering entering host- binds and signals for macrophage

41
Q

what are the 4 types of immunity?

A

active artificial- immune after vaccination

active natural- immune after initial exposure

passive artificial- infected by antibodies

passive natural- antibodies from mothers

42
Q

why don’t vaccines eliminate all disease?

A

immunodeficiency
antigenic variability
objections
different strains

43
Q

what does HIV do to helper T cells?

A

replicate inside them causing them to swell and burst

44
Q

describe the structure of HIV

A

attachment protein
lipid envelope
RNA
capsid
matrix
reverse transcriptase

45
Q

how does HIV replicate?

A

binds to CD4 protein on helper T cell

capsid fuses with membrane and RNA/enzymes enter

HIV reverse transcriptase coverts HIV RNA into DNA

moved into nucleus and inserted into cells DNA

creates mRNA which leaves through nuclear pore to be used in protein synthesis

46
Q

what are monoclonal antibodies a clone of?

A

a single B cell

47
Q

describe the hybridoma method of making monoclonal antibodies

A

mouse injected with antigen which simulates the production of plasma cells

bound with rapid dividing tumour cell to form a hybridoma which is assisted with an electrical current of polyethene glycol

grown in selective growth medium

cultured to produce large quantities of monoclonal antibodies

48
Q

how does ELISA testing work?

A

apply to surface and wash to remove unattached antigens

add antibody and wash

add second antibody with an enzyme

add colourless substrate and look for a colour change

AQA A level biology <33 (12 decks)

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