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Biology - AQA - Extras > AO1 - Unit 2 > Flashcards

AO1 - Unit 2 Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

All cells arise from other ______________

A

cells

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2
Q

Prokaryotic cells form new cells by ______________ _______________

A

binary fission

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3
Q

Name two types of cell division.

A

mitosis and meiosis

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4
Q

What is the role of the cell surface membrane?

A

Selectively permeable to control the exchange of material

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5
Q

Give two types of molecule found in plasma membranes.

A

phospholipids, proteins

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6
Q

Which type of cell has internal membranes?

A

eukaryotic cell

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7
Q

What is the role of the nucleus?

A

stores DNA in the form of chromatin

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8
Q

What is the role of the nucleolus?

A

makes ribosomes

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9
Q

What is the role of chloroplasts?

A

absorb light energy for photosynthesis

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10
Q

Where are chloroplasts found?

A

plants and algae

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11
Q

What is role of Golgi apparatus?

A

modifies and packages proteins, adds carbohydrates to form glycoproteins

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12
Q

What type of cell will have a lot of Golgi apparatus?

A

cells which secrete proteins or glycoproteins such as beta cells of the islets of langerhans

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13
Q

What is the role of lysosomes?

A

contain lysosymes which hydrolyse pathogens or worn out organelles

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14
Q

What is the difference between RER and SER?

A

rough contains ribosomes on surface, smooth does not

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15
Q

What is the role of the RER?

A

transports proteins made at ribosomes

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16
Q

What is the role of the SER?

A

synthesise, store and secrete lipids

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17
Q

What type of cell have a cell wall?

A

prokaryotes and some eukaryotes - plants, fungi

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18
Q

Eukaryotic cells undergo what to become suited to a particular job?

A

differentiation/specialisation

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19
Q

Name a cell that has microvilli.

A

epithelial cells of the ileum

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20
Q

Where are cristae found?

A

mitochondria

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21
Q

What is the role of the cell vacuole?

A

storage of water/sugars needed for growth, waste disposal and turgidity

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22
Q

Give 4 differences between prokaryotic and eukaryotic cells.

A

linear DNA vs circular DNA / nucleus vs no nucleus / membrane bound organelles vs none (like mitochondria, chloroplast, golgi body) / 80S ribosomes vs 70S ribosomes

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23
Q

What type of cell has a plasmid?

A

prokaryotes / bacteria

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24
Q

What type of particle is described as acellular and non-living?

A

virus

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25
Q

What stain is used to locate starch grains in a plant cell?

A

iodine

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26
Q

How is magnification calculated?

A

magnification = image size / actual size

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27
Q

How many micrometres in a mm?

A

1000

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28
Q

What is resolution?

A

minimum distance two objects can be seen to be distinct from one another

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29
Q

Explain why electron microscope has a greater resolving power than optical microscope.

A

shorter wavelength of electrons

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30
Q

In microscopy, what is an artefact?

A

something introduced to the image during preperation, excess stain for example, which is not naturally there

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31
Q

What is cell fractionation used for?

A

separate out organelles for study

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32
Q

What is homogenisation?

A

blending or breaking open cells to release contents

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33
Q

Give 3 properties of the solution used to homogenise the tissue

A

isotonic, ice cold and pH buffered

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34
Q

Why is the mixture filtered after homogenisation?

A

remove any debris which may have similar mass to organelles

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35
Q

Why do organelles separate out during centrifugation?

A

based on mass - heavier will go to bottom at lower speeds

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36
Q

After centrifugation what is left at the bottom of the tube?

A

pellet - heaviest organelles first

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37
Q

What do we call the fluid above it?

A

supernatant

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38
Q

In what order will organelles separate out?

A

nucleus, mitochondria/chloroplast, lysosomes, endoplasmic reticulum, ribosomes

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39
Q

During which stage of the cell cycle does DNA replication occur?

A

interphase - S phase

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40
Q

Which part of the cell cycle produces 2 identical daughter cells?

A

mitosis

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41
Q

How would you describe DNA replication?

A

semi-conservative

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42
Q

Where do centromeres attach during mitosis?

A

spindle

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43
Q

Name the stages of mitosis

A

prophase, metaphase, anaphase, telophase

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44
Q

What is cytokinesis?

A

seperation of the cell membranes to create two daughter cells

45
Q

What leads to the formation of tumours and cancers?

A

uncontrolled mitosis

46
Q

Many cancer treatments target what?

A

DNA synthesis in interphase of rapidly dividing cells

47
Q

Do viruses undergo cell division?

A

no, they invade and reproduce inside other cells

48
Q

Why are root tips used to study mitosis?

A

lots of mitosis occuring in growing tip, more likely to see each stage

49
Q

How is mitotic index calculated?

A

number of cells in mitosis/total number of cells observed

50
Q

Name a stain used to stain chromosomes?

A

giemsa

51
Q

What is binary fission?

A

bacteria dividing from one parent cell to two daughter cells

52
Q

Do plasmids replicate in binary fission?

A

yes, can be lots of times

53
Q

Are internal membranes the same structure as the plasma membrane?

A

yes

54
Q

How is membrane structure described?

A

fluid mosaic model / phospholipid bilayer with embedded proteins and glycoproteins

55
Q

How do small lipid soluble substances cross the membrane?

A

simple diffusion

56
Q

How does facilitated diffusion differ from simple diffusion?

A

carrier or channel proteins needed

57
Q

What is osmosis?

A

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

58
Q

What is a hypertonic solution?

A

solution that has a lower water potential than the cell

59
Q

What is a hypotonic solution?

A

solution that has a higher water potential than the cell

60
Q

What is an isotonic solution?

A

solution that has the same water potential than the cell

61
Q

What is active transport?

A

movement of particles against the concentration gradient (low to high concentration) using a carrier protein and ATP for energy

62
Q

What provides the energy for active transport?

A

ATP hydrolysis

63
Q

How is Active transport similar to facilitated diffusion?

A

both use transport proteins

64
Q

How is Active transport different to facilitated diffusion?

A

AT against the conc.grad and uses ATP (energy) whereas FD is passive and down the conc.grad

65
Q

When is Active transport reduced or stopped?

A

when ATP can no longer be hydrolysed or transport proteins are saturated

66
Q

Give an example of where co-transport occurs?

A

ileum of the small intestine

67
Q

How are cells adapted for rapid transport of substances?

A

lots of mitochondria, microvilli, lots of carrier/channel proteins

68
Q

What is a calibration curve?

A

general method for determining the concentration of a substance in an unknown sample by comparing the unknown to a set of standard samples of known concentration.

69
Q

What is a calibration curve used for?

A

general method for determining the concentration of a substance in an unknown sample by comparing the unknown to a set of standard samples of known concentration.

70
Q

When investigating water potential why is % change often used?

A

allows comparisons, tissues may have different starting masses

71
Q

What is an antigen?

A

foreign protein that stimulates an immune response

72
Q

What is a pathogen?

A

microorganism that causes harm to /infects a host

73
Q

What 4 things can induce an immune response?

A

foreign cells, pathogens, cancer cells, abnormal cells, APC

74
Q

What is a phagocyte?

A

a type of white blood cell which carries out phagocytosis

75
Q

What are lysozymes?

A

hydrolytic enzymes found in lysosomes

76
Q

What is antigenic variation?

A

change in the shape of the protein antigen of pathogens due to mutation

77
Q

What leads to antigenic variability?

A

mutations

78
Q

What is a capsid?

A

virus’s protein coat

79
Q

What is the cellular response?

A

immune response lead by T cells

80
Q

Give 2 examples of non-specific immunity

A

phagocytosis, chemical barriers such as stomach acid and physical barriers such as skin

81
Q

What does active immunity involve?

A

production of antibodies

82
Q

How are antibodies described?

A

proteins with a quaternery structure of 4 polypeptide chains held together with disulphide bridges

83
Q

What is an antigen presenting cell?

A

a cells which displays the antigens of a digested pathogen on its surface - after phagocytosis

84
Q

What detects antigen presenting cells?

A

specific T cells and B cells

85
Q

Once stimulated helper T cells stimulate which other cells?

A

phagocytes, cytotoxic T cells and B cells

86
Q

Once stimulated how do B cells divide?

A

mitosis / clonal selection

87
Q

What is formed when B cells multiply?

A

plasma cells and some memory cells

88
Q

Which type of cell secretes antibodies?

A

plasma cells

89
Q

Antibodies carry out what type of immune response?

A

humoral response

90
Q

Which type of cell carries out the cellular immune response?

A

T cells

91
Q

How do cytotoxic cells work?

A

T cells which destroy an infected cell directly by releasing perforin/hydrogen peroxide which punctures the cell membrane

92
Q

What is passive immunity?

A

immunity required by acquiring antibodies

93
Q

Give a disadvantage of passive immunity

A

not as long lasting as active immunity

94
Q

Give an example of passive immunity

A

antibodies passed via breast milk

95
Q

How does the secondary immune response differ from the primary immune response?

A

quicker increase in concentration of antibodies and higher concentrations of antibodies

96
Q

What are monoclonal antibodies?

A

antibodies with the same tertiary structure specific to one type of antigen

97
Q

Give 2 uses of monoclonal antibodies

A

cancer treatment / pregnancy tests

98
Q

What is herd immunity?

A

when a high enough proportion of individuals in a population are immune (through vaccination) those who are not are still protected

99
Q

Name 3 things a vaccine may contain

A

attenuated pathogen, antigens, toxins

100
Q

What does HIV stand for?

A

human immunodeficiency virus

101
Q

What type of microorganism is HIV?

A

retro virus

102
Q

What does HIV contain?

A

RNA, proteins such as reverse transcriptase, lipid envelope, capsid and attachment proteins

103
Q

What is role of reverse transcriptase?

A

make copies of DNA from RNA

104
Q

What type of cell is infected by HIV?

A

Helper T cells

105
Q

What does HIV infection lead to after a latent period?

A

reduced TH cell count, reduced immune system and therefore increased susceptibility to infection

106
Q

What does ELISA stand for?

A

Enzyme Linked Immunosorbant Assay

107
Q

what are the two types of ELISA?

A

direct and indirect ELISA

108
Q

What does a labelled antibody look like

A

Biology - AQA - Extras (15 decks)

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