Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

A-Level Bio > Topic 2 > Flashcards

Topic 2 Flashcards

1
Q

Nucleus structure

A

Double membraned nuclear envelope
nuclear pores
nucleoplasm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Nucleus function

A

Site of DNA replication
Contains genetic code for each cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Endoplasmic reticulum types

A

smooth
rough

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

RER function

A

protein synthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

SER function

A

synthesis and storage of lipids and carbohydrates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Structure of Golgi apparatus

A

folded membranes making cisternae
secretary vesicles pinch off of cisternae

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Functions of golgi apparatus (4)

A
  1. add carbs to proteins forming glycoproteins
  2. produce secretory enzymes
  3. secrete carbohydrates
  4. transport, modify and store lipids
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Functions of lysosomes (4)

A

hydrolyse phagocyte’s engulfed pathogens
autolysis of dead cells
exocytosis to destroy material outside cells
digest worn out organelles for reuse of materials

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

structure of mitochondria

A

double membrane
inner membrane = cristae
fluid centre = mitochondrial matrix
loop of mitochondrial DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

function of mitochondria

A

site of aerobic respiration (chemiosmosis)
site of ATP production
DNA to code for enzymes needed in respiration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

ribosome structure

A

2 units = protein and rRNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

ribosome function

A

site of protein synthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

structure of vacuole

A

filled with fluid
surrounded by single membrane called a tonoplast

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

vacuole function

A

make cells turgid and therefore provide support
temp storage of AAs and sugars
the pigments may colour petals to attract pollinators

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

chloroplast structure

A

surrounded by a double membrane
contains thylakoids
fluid filled stroma contains photosynthetic enzymes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

cell wall structure in plants

A

microfibrils of cellulose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

cell wall structure in fungi

A

made of chitin (polysaccharide)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

difference between eukaryotic cells and prokaryotic cells

A

Prokaryotes:

smaller cells
no membrane bound organelles
no nucleus
murein cell wall
have no proteins associated with their DNA (no histones)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Why is it hard to get rid of a virus without harming own cells?

A

they replicate inside host cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Structure of a virus

A

genetic material
capsid
attachment protein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

magnification definition

A

how many times larger an image is compared to its object

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

resolution definition

A

minimum distance between two objects in which they can still be viewed as separate to each other

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

optical microscopes vs electron (5)

A

O:
beam of light condensed to create image
poorer res due to longer light wl
lower magnification
colour images
viewing living samples

E:
beam of e- condensed to create it
higher res due to shorter e- wl
higher magnification
b&w images
non living as it needs to be in a vacuum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

why can’t OMs be used to see small organelles while EMs can?

A

lower resolution than EMs
due to light having longer wavelengths than an electron beam condensed by electromagnets

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Why must EMs be used in a vacuum

A

air absorbs electrons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

how a TEM works

A

thin specimens stained and placed in vacuum
electron gun allows e- to pass through specimen
darker parts absorb electrons
produces 2d image

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

how a SEM works

A

electrons beamed onto the surface and are scattered differently depending on contours
produces a 3D image

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

magnification equation

A

I=AM

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

metre to mm to micrometre to nanometre

A

x1000

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

nanometre to micrometre to mm to metre

A

/1000

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

what is cell fractionation for?

A

studying isolated organelle structures and functions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Why fractionate cells in a cold, isotonic and buffered solution?

A

reduces enzyme activity so they don’t damage organelles after the cell breaks open

prevents osmosis causing organelles to not shrivel/burst

prevents damage to organelles with pH buffer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

cell fractionation 2 steps

A

homogenisation
ultracentrifugation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

homogenisation steps

A

use a blender and blend cells in cold, buffered and isotonic solution
filter to remove large cell debris

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

ultracentrifugation steps

A

filtered solution is spun at increasing speeds, removing supernatant each time to isolate the pellet and spinning the supernatants
organelles separate according to their densities

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

why do the most dense pellets form first?

A

due to the centrifugal force

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

order of organelles retrieved from centrifugation

A

nuclei
chloroplasts
mitochondria
lysosomes
ER
ribosomes

38
Q

eukaryotic cell division

A

mitosis or meiosis

39
Q

prokaryotic cell division

A

binary fission

40
Q

virus cell division

A

doesn’t happen - non living

41
Q

how do viruses replicate

A

inside host cells by injecting nucleic acid into the cell to replicate and assemble viral particles

42
Q

Interphase stages

A

G1 growth
S DNA synthesis
G2 growth and preparation for nuclear division

43
Q

4 Mitosis key features

A

one round of division
produces genetically identical cells
diploid cells are made
for growth and repair eg clonal expansion of B cells

44
Q

Prophase of mitosis

A

chromosomes condense and become visible
centrioles move to opposite poles of the cell
nuclear envelope disappears

45
Q

metaphase of mitosis

A

chromosomes align along equator of cell
spindle fibres attach to the centromere and chromatid

46
Q

anaphase of mitosis

A

chromosomes break at cemtromeres and sister chromatids move to opposite ends of the cell
requires energy from ATP

47
Q

telophase of mitosis

A

nuclear envelope reforms
chromosomes unwind again
spindle fibres disintegrate
cytokinesis follows

48
Q

mitotic index =

A

(no of cells in mitosis/total no of cells)x100

49
Q

binary fission steps

A

replication of circular DNA and plasmids

cytoplasm divides to produce 2 daughter cells each with a copy of circular DNA and a variable number of plasmids

50
Q

molecules that can pass through the plasma membrane

A

lipid soluble substances
very small molecules

51
Q

molecules that can’t pass through the plasma membrane

A

polar molecules (water soluble/ions)
large molecules

52
Q

simple diffusion is for ____ molecules

A

small and lipid soluble

53
Q

protein channels allow ___ molecules to pass

A

large, water soluble ions and polar molecules

54
Q

how do carrier proteins allow ions and polar substances to pass through?

A

bind to the molecule
causes change of protein’s shape
so molecule is released on other side

55
Q

osmosis definition

A

movement of water from area of high water potential to area of low water potential across a partially permeable membrane

56
Q

what is wp and what is it measured in?

A

pressure created by water molecules

kPa

57
Q

Pure water WP

A

0

58
Q

hypotonic solution

A

water potential of a solution is more positive than the cell

59
Q

hypertonic solution

A

water potential of a solution is more negative than the cell

60
Q

active transport definition

A

movement of substance from low to high conc using energy from ATP and carrier proteins

61
Q

how AT works

A

molecule binds to receptor complementary in shape on carrier protein
ATP binds to carrier protein on inside of cell and is hydrolysed to ADP and Pi
Energy released is used and the protein changes shape, letting the molecule in
The phosphate ion is released and the protein’s original shape reforms

62
Q

Co transport steps

A
  1. Na+ AT out of epithelial cell into blood
  2. Na+ diffuses into epithelial cell from ileum lumen down conc grad
  3. Symport brings in both Na+ and glucose/AAs simultaneously against their conc grad
63
Q

Adaptations for rapid transport

A

increase in SA
increase in no of channel proteins/carrier proteins

64
Q

How can lymphocytes distinguish between self and non self pathogens

A

unique cell surface receptors

65
Q

non self cells that can be identified

A

pathogens
cells from other organisms of the same species
abnormal body cells
toxins

66
Q

antigens are

A

molecules generating an immune response by lymphocyte cells when detected in the body
usually proteins

67
Q

antigen variability

A

occurs when a gene coding for an antigen is mutated, changing its shape

previous immunity is no longer effective as memory cells only work for the old antigen shape

68
Q

second line of defence

A

white blood cells

69
Q

phagocytosis steps

A

macrophage is attracted to chemicals released by the pathogen
attaches to the antigens of it
engulfs the pathogen
lysosomes fuse with the phagosome and release its lysozymes, hydrolysing the pathogen

70
Q

where do T cells mature

A

the Thymus

71
Q

4 APCs

A

infected body cells
macrophages after engulfing and destroying a pathogen
cells of a transplanted organ
cancer cells

72
Q

Cell mediated response 3 steps

A
  1. TH cell receptors bind to the APC antigens
  2. activates TH cells to divide by mitosis and make large numbers of clones
  3. some of the cloned cells either
    remain as TH cells and activate Bcells
    stimulate macrophages to perform more phagocytosis
    become memory cells for that shaped antigen
    become cytotoxic T cells
73
Q

How do Tk cells kill abnormal/infected cells?

A

release perforin
embeds in CSM
makes a pore so any substances can move in and out of the cell
causes cell death
common in viral infections

74
Q

Humoral immunity steps

A
  1. antigens in blood collide with complementary antibody on B cell, which takes it in by endocytosis and presents it on its cell membrane
  2. when this APC B cell collides with a Th cell, it activates the B cell to go through clonal selection to make large nos of plasma cells or memory B cells
    plasma cells= make antibodies
    memory b cells= can divide into plasma cells rapidly on reinfection with the same pathogen for many antibodies to be produced quickly
75
Q

memory b cells vs plasma cells

A

MB live for decades
plasma cells are short lives

76
Q

What do antibodies do

A

agglutination of antigen antibody complexes
makes it easier for phagocytes to locate and destroy pathogens

77
Q

passive immunity

A

antibodies introduced to body
no long term immunity as plasma cells/ memory cells aren’t made
eg antibodies to fetus from placenta or from breast milk to a baby

78
Q

active immunity

A

immunity created by your own immune system following exposure to a pathogen or its antigen

79
Q

when does natural active immunity occur?

A

after infection and response creating memory cells and plasma cells

80
Q

when does artificial immunity occur?

A

following introduction of a weakened version of a pathogen or antigens via a vaccine

81
Q

vaccines steps to providing immunity

A
  1. inject live attenuated or dead pathogen or take it orally
  2. exposure to antigens stimulate B cell to go through clonal expansion and differentiation
  3. B cells undergo mitosis to make large numbers of plasma cells or memory B cells
  4. plasma cells make antibodies and memory b cells divide into plasma cells rapidly on reinfection with the same pathogen
82
Q

HIV structure

A

core with genetic material and reverse transcriptase enzyme
capsid
envelope (extra outer layer)
protein attachments enabling it to attach to T cells

83
Q

HIV replication in TH cells

A
  1. HIV attaches to CD4 protein
  2. HIV protein capsule fuses with the TH cell membrane enabling the RNA and enzymes to enter
  3. reverse transcriptase copies viral RNA to DNA and moves to the Th cell nucleus
  4. mRNA is transcribed and the Th cell produces viral proteins to form new viral particles
84
Q

what is AIDS

A

When replicating HIV in Th cells interferes with immune system function
leaves them vulnerable to cancer and infections

85
Q

monoclonal antibody meaning

A

a single antibody that can be isolated and cloned

86
Q

antibody definition

A

proteins with binding sites complementary in shape to certain antigens

87
Q

3 uses of monoclonal antibodies

A

medical treatment
medical diagnosis
pregnancy tests

88
Q

indirect monoclonal antibody therapy

A

antibodies given to cancer patients
due to complementary shapes they bind to antigens on cancer cells preventing the chemicals enabling uncontrolled division from doing so

89
Q

Direct monoclonal antibody therapy

A

MAs complementary to cancer cell antigens bind but have a drug attached, which is delivered only to cancer cells and kills them
reduces harmful side effects of traditional chemotherapy

90
Q

5 diagnoses that require MAs

A

pregnancy
influenza
hepatitis
chlamydia
prostate cancer

91
Q

Elisa test steps

A
  1. add test sample to base of beaker and wash off any unbound test sample
  2. add an antibody complementary to the antigen being tested for to the sample
  3. wash to remove any unbound antibody
  4. add a second antibody (which has an enzyme attached) that’s complementary to the first
  5. the (colourless) enzyme for the substrate is added, producing coloured products in the presence of the enzyme
  6. colour presence indicates presence of antigen in the test and intensity indicates the quantity present
92
Q

ethical issues with using MAs

A

requires mice to produce antibodies and tumour cells
but may be justified to treat cancer in humans and detect disease

A-Level Bio (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions