Brainscape's Knowledge GenomeTM

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


See full index

Biology > topic 2 > Flashcards

topic 2 Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

Cell membrane structure

A

Phospholipid bilayer with embedded intrinsic & extrinsic proteins

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

Cell membrane function

A

Selectively permeable barrier controls passage of substances in and out the cell
barrier between internal and external cell environments

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

Nucleus Structure

A

Nuclear pores, nucleolus, DNA and nuclear envelope

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

Nucleus Function

A

Site of transcription & pre- mRNA splicing - mRNA production
site of DNA replication nucleolus makes ribosomes nuclear pore allows movement of substances to/from cytoplasm

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

Mitochondria Structure

A

Double membrane with inner membrane folded into cristae 70S ribosomes in matrix small, circular DNA
enzymes in matrix

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

Mitochondria Function

A

Site of aerobic respiration produces ATP

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

Chloroplast structure

A

Thylakoid membranes stacked to form grana, linked by lamellae
stroma contains enzymes contains starch granules, small circular DNA and 70S ribosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Chloroplast function

A

Chlorophyll absorbs light for photosynthesis to produce organic molecules (glucose)

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

Organisms containing
chloroplasts

A

Plants
Algae

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

Golgi apparatus stucture

A

Fluid-filled, membrane-bound sacs (horseshoe shaped) vesicles at edge

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

Golgi apparatus function

A

Modifies proteins received from RER
packages them into vesicles to transport to cell membrane for exocytosis
makes lysosomes

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

Lysosome structure

A

Type of Golgi vesicle containing digestive enzymes

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

Lysosome function

A

Contains digestive enzymes e.g lysozymes to hydrolyse pathogens/cell waste products

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

Rough endoplasmic reticulum function

A

Site of protein synthesis
folds polypeptides to secondary & tertiary structures packaging into vesicles to transport to Golgi

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

Smooth endoplasmic reticulum function

A

Synthesises and processes lipids

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

Cell wall function

A

Provides structural strength, rigidity and support to cell helps resist osmotic pressures

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

Ribosome structure

A

Small and large subunit made of protein and rRNA free floating in cytoplasm & bound to RER
70S in prokaryotes, mitochondria and chloroplasts 80S in eukaryotes

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

Ribosome function

A

Site of translation in protein synthesis

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

Rough endoplasmic reticulum structure

A

System of membranes with bound ribosomes continuous with nucleus

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

Smooth endoplasmic reticulum structure

A

System of membranes with no bound ribosomes

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

Cell wall structure

A

In plant, fungal and bacterial cells
plants - made of microfibrils of cellulose
fungi - made of chitin bacteria - murein

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

Cell vacuole structure

A

Fluid-filled
surrounded by a single membrane called a tonoplast

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

Contrast prokaryotic &
eukaryotic cells

A

Prokaryotic cells are smaller prokaryotes have no membrane bound organelles
prokaryotes have smaller 70S ribosomes
prokaryotes have no nucleus - circular DNA not associated with histones
prokaryotic cell wall made of murein instead of cellulose/chitin

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

Occasional features of prokaryotes

A

Plasmids - loops of DNA capsule surrounding cell wall - helps agglutination + adds protection
flagella for movement

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

Cell vacuole function

A

Makes cells turgid - structural support
temporary store of sugars, amino acids
coloured pigments attract pollinators

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

Protein carriers

A

Bind with a molecule, e.g. glucose, which causes a change in the shape of the protein
this change in shape enables the molecule to be released to the other side of the membrane

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

Protein channels

A

Tubes filled with water enabling water-soluble ions to pass through the membrane selective
channel proteins only open in the presence of certain ions when they bind to the protein

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

Features of viruses

A

Non living and acellular
contain genetic material, capsid and attachment proteins
some (HIV) contain a lipid envelope + enzymes (reverse transcriptase)

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

3 types of microscopes

A

Optical (light) microscopes Scanning electron microscopes
(SEM)
Transmission electron
microscopes (TEM)

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

Magnification

A

How many times larger the image is compared to the object calculated by equation:

magnification = image size/actual size

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

Resolution

A

The minimum distance between two objects in which they can still be viewed as separate determined by wavelength of light (for optical microscopes) or electrons (for electron microcopes)

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

Optical microscopes

A

Beam of light used to create image
glass lens used for focusing 2D coloured image produced

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

Evaluate optical microscopes

A

Poorer resolution as long wavelength of light - small organelles not visible lower magnification
can view living samples simple staining method vaccum not required

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

Transmission electron microscopes

A

Beam of electrons passes through the sample used to create an image
focused using electromagnets 2D, black & white image produced
can see internal ultrastructure of cell
structures absorb electrons and appear dark

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

Evaluation TEMs

A

Highest resolving power high magnification extremely thin specimens required
complex staining method specimen must be dead vaccum required

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

Scanning electron microscopes

A

Beam of electrons pass across sample used to create image focused using electromagnets 3D, black and white image produced
electrons scattered across specimen producing image

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

Evaluation SEMs

A

High resolving power high magnification
thick specimens usable complex staining method specimen must be dead vaccum required

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Why calibrate eyepiece graticule?

A

Calibration of the eyepiece is required each time the objective lens is changed
calibrate to work out the distance between each division at that magnification

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Purpose of cell fractionation

A

Break open cells & remove cell debris
so organelles can be studied

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Homogenisation

A

Process by which cells are broken open so organelles are free to be separated
done using homogeniser (blender)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Homogenisation conditions

A

Cold reduces enzyme activity preventing organelle digestion Isotonic prevents movement of water by osmosis - no bursting / shrivelling of organelles Buffered resists pH changes preventing organelle + enzyme damage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Ultra- centrifugation

A

Homogenate solution filtered to remove cell debris
solution placed in a centrifuge which spins at a low speed initially
then increasingly faster speeds to separate organelles according to their density

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Differential centrifugation

A

Supernatant first out (spun at lowest speed) is most dense = nuclei
spun at higher speeds chloroplasts -> mitochondria -> lysosomes -> RER/SER -> ribosomes (least dense)

44
Q

Binary Fission

A

Involves circular DNA & plasmids replicating cytokinesis creates two daughter nuclei
each daughter cell has one copy of circular DNA and a variable number of plasmids

45
Q

Cell cycle

A

1) Interphase (G1, S, G2)
2) nuclear division - mitosis or meiosis
3) cytokinesis

46
Q

Interphase

A

Longest stage in the cell cycle when DNA replicates (S-phase) and organelles duplicate while cell grows (G1&G2-phase)
DNA replicates and appears as two sister chromatids held by centromere

47
Q

Mitosis

A

One round of cell division
two diploid, genetically identical daughter cells growth and repair (e.g. clonal expansion)
comprised of prophase, metaphase, anaphase and telophase

48
Q

Prophase

A

Chromosomes condense and become visible
nuclear envelope disintegrates in animals - centrioles separate & spindle fibre structure forms

49
Q

Metaphase

A

Chromosomes align along equator of cell
spindle fibres released from poles now attach to centromere and chromatid

50
Q

Anaphase

A

Spindle fibre contracts (using ATP) to pull chromatids, centromere first, towards opposite poles of cell centromere divides in two

51
Q

Telophase

A

Chromosomes at each pole become longer and thinner again
spindle fibres disintegrate + nucleus reforms

52
Q

Mitotic index

A

Used to determine proportion of cells undergoing mitosis Calculated as a percentage OR decimal
x100 for percentage

mitotic index = number of cells in mitosis/total number of cells

53
Q

Fluid mosaic model

A

Describes the lateral movement of membranes
with scattered embedded intrinsic and extrinsic proteins membrane contains glycoproteins, glycolipids, phospholipids and cholesterol

54
Q

Phospholipids in membranes

A

Phospholipids align as a bilayer hydrophilic heads are attracted to water
hydrophobic tails repelled by water

55
Q

Cholesterol

A

Present in eukaryotic organisms to restrict lateral movement of the membranes
adds rigidity to membrane- resistant to high temperatures & prevents water + dissolved ions leaking out

56
Q

Selectively permeable membrane

A

Molecules must have specific properties to pass through plasma membrane
lipid soluble (hormones e.g. oestrogen)
very small molecules non-polar molecules (oxygen)

57
Q

Simple diffusion

A

Net movement of molecules from an area of higher concentration to an area of lower concentration
until equilibrium is reached
passive

58
Q

Facilitated diffusion

A

Passive process using protein channels/carriers
down the concentration gradient
used for ions and polar molecules e.e sodium ions
and large molecules e.g. glucose

59
Q

Osmosis

A

Net movement of water
from an area of higher water potential to an area of lower (more negative) water potential across a partially permeable membrane

60
Q

Water potential

A

The pressure created by water molecules
measured in kPa and represented by symbol ψ
pure water has a water potential of 0kPa
the more negative the water potential, the more solute must be dissolved

61
Q

Hypertonic solution

A

When the water potential of a solution is more negative than the cell
water moves out of the cell by osmosis
both animal and plant cells will shrink and shrivel

62
Q

Hypotonic solution

A

When the water potential of a solution is more positive (closer to zero) than the cell
water moves into the cell by osmosis
animal cells will lyse (burst) plant cells will become turgid

63
Q

Isotonic

A

When the water potential of the surrounding solution is the same as the water potential inside the cell
no net movement in water cells would remain the same mass

64
Q

Active transport

A

The movement of ions and molecules from an area of lower concentration to an area of higher concentration using ATP and carrier proteins
carrier proteins act as selective pumps to move substances

65
Q

Role of carrier protein in active transport

A

When molecules bind to the receptor - ATP will bind to protein on inside of membrane and is hydrolysed to ATP / Pi protein changes shape and opens inside membrane

66
Q

Co-transport

A

The movement of two substances across a membrane together, when one is unable to cross the membrane itself involves a cotransport protein involves active transport
e.g. absorption of glucose/amino acids from lumen of intestines

67
Q

Molecules lymphocytes identify

A

Pathogens (bacteria, fungi, viruses)
cells from other organisms of same species (transplants) abnormal body cells (tumour cells)
toxins (released from bacteria)

68
Q

Antigens

A

Proteins on the cell-surface membrane
trigger an immune response when detected by lymphocytes

69
Q

Antigenic variability

A

When pathogenic DNA mutates causing a change in shape of antigen
previous immunity is no longer effective as memory cells don’t recognise new shape of antigen. specific antibody no longer binds to new antigen

70
Q

Physical barriers

A

Anatomical barriers to pathogens
skin
stomach acid
lysozymes in tears

71
Q

Phagocytes

A

Non-specific immune response phagocytes become antigen- presenting cells after destroying pathogen

72
Q

T lymphocytes

A

Made in bone marrow and mature in thymus gland involved in cell-mediated immune response
respond to antigen-presenting cells

73
Q

Antigen- presenting cells

A

Any cell that presents a non-self antigen on their surface
infected body cells macrophage after phagocytosis
cells of transplanted organ cancer cells

74
Q

Role of T helper cells

A

Have receptors on their surface that attach to antigens on APCs become activated - clonal selection

75
Q

Role of cloned T helper cells

A

Some remain as helper T cells &
activate B lymphocytes
stimulate macrophages for
phagocytosis
become memory cells for that shaped antigen
become cytotoxic killer T cells

76
Q

Cytotoxic T cells

A

Destroy abnormal / infected cells by releasing perforin
so that any substances can enter or leave the cell and this causes cell death

77
Q

B lymphocytes

A

Made in bone marrow and mature in bone marrow involved in humoral immune response
involves antibodies

78
Q

Humoral response

A

APC activates B cell
B cell undergoes clonal selection and expansion - rapid division by mitosis. differentiate into plasma cells / memory B cells
plasma cells make antibodies

79
Q

B memory cells

A

derived from B lymphocytes remember specific antibody for particular antigen
will rapidly divide by mitosis and differentiate in plasma cells upon secondary encounter resulting in large numbers of antibodies rapidly

80
Q

Antibodies

A

Quaternary structure proteins made of four polypeptide chains different shaped binding site = variable region
complementary to a specific antigen

81
Q

Antibody structure

A

antigen binding sites
variable region
light chain
heavy chain
constant region

82
Q

Agglutination

A

Antibodies have two binding sites and are flexible - clumps pathogens together
makes it easier for phagocytes to locate and destroy pathogen

83
Q

Passive immunity

A

Antibodies introduced into body plasma and memory cells not made as no interaction with antigen
short-term immunity fast acting

84
Q

Active immunity

A

Immunity created by own immune system - antibodies made
exposure to antigen
plasma and memory cells made
long term immunity
slower acting

85
Q

Natural active immunity

A

After direct contact with pathogen through infection body creates antibodies and memory cells

86
Q

Artificial active immunity

A

Creation of antibodies and memory cells following introduction of an attenuated
pathogen or antigens vaccination

87
Q

Vaccinations

A

Small amounts of dead or attenuated pathogens injected / ingested
humoral response activated memory cells are able to divide rapidly into plasma cells when re-infected

88
Q

Primary vs Secondary response

A

Primary = first exposure to the pathogen
longer time for plasma cell secretion & memory cell production
for the secondary response, memory cells divide rapidly into plasma cells
so a large number of antibodies made rapidly upon reinfection

89
Q

Herd immunity

A

When enough of the population is vaccinated so pathogen is not transmitted and spread easily provides protection for those without vaccine

90
Q

Monoclonal antibodies

A

A single type of antibody that can be isolated and cloned antibodies that are identical - from one type of B lymphocyte complementary to only one antigen

91
Q

Uses of monoclonal antibodies

A

Medical treatment - targeting drugs by attaching antibody complementary to tumour cell antigen
medical diagnosis - pregnancy tests

92
Q

Pregnancy test

A

ELISA test which uses 3 monoclonal antibodies and enzymes to test for hCG

93
Q

Purpose of ELISA test

A

Detect the presence and quantity of an antigen
used for medical diagnosis. Eg., HIV

94
Q

Ethical issues with monoclonal antibodies

A

Requires mice to produce antibodies and tumour cells requires a full cost-benefit analysis

95
Q

HIV structure

A

Core = RNA and reverse transcriptase
capsid = protein coat
lipid envelope taken from hosts cell membrane
attachment proteins so it can attach to Helper T cells

96
Q

HIV replication

A

Attaches to CD4 receptor on helper T cells
protein fuses with membrane allowing RNA + enzymes to enter reverse transcriptase makes DNA copy and this is inserted into nucleus
nucleus synthesises viral proteins

97
Q

Auto Immunodeficiency Syndrome (AIDs)

A

When HIV has destroyed too many T helper cells, host is unable to produce adequate immune response to other pathogens
host susceptible to
opportunistic infections

98
Q

Role of antibodies in ELISA

A

First antibody added is complementary to antigen in well - attaches
second antibody with enzyme added which attaches to first antibody as complementary. when substrate solution added enzyme can produce colour change

99
Q

Why vaccines may be unsafe

A

Inactive virus may become active - viral transformation non-pathogenic virus can mutate and harm cells
side effects of immune response
people may test positive for disease

100
Q

Why are antibiotics ineffective against viruses?

A

Viruses are inside host cells where antibiotics cannot reach antibiotics affect parts of bacteria that viruses do not have (e.g the cell wall)

101
Q

Why do you wash well in ELISA

A

Removes unbound 2nd antibodies
otherwise enzyme may be present colour change false positive

102
Q

Pathogens

A

Microorganisms that cause a disease
by releasing toxins or killing cells / tissues

103
Q

Cytokinesis

A

Final stage in the cell cycle when the cytoplasm splits in two
creates two new cells

104
Q

Uncontrolled mitosis

A

Uncontrolled cell division can lead to the formation of tumours and of cancers
many cancer treatments are directed at controlling the rate of cell division

105
Q

Viral replication

A

Following injection of their nucleic acid
the infected host cell replicates the virus particles

106
Q

Cell adaptations for rapid transport across membranes?

A

Increase in surface area or membrane
increase in the number of protein channels and carrier molecules in the membranes

107
Q

Antigen- antibody complex

A

When a complementary
antibody binds to an antigen
this clumps pathogens together (agglutination)

Biology (5 decks)

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