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A-Level Biology > 2 - Cells and Microscopy > Flashcards

2 - Cells and Microscopy Flashcards

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1
Q

Nucleus structure

A

Surrounded by a double membrane nuclear envelope with nuclear pores. Has chromosomes, (protein-bound, linear DNA) and one or more nucleolus

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2
Q

Nucleus function

A

Nucleolus - site of rRNA product and makes ribosomes. DNA replication and transcription

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3
Q

Cell membrane structre

A

Phospholipid bilayer

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4
Q

Cell membrane function

A

Transport, cell recognition, fluidity, receptor

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5
Q

SER structure

A

No ribosomes. Sheet like membranes linked to nucleus, form cisternae

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6
Q

SER function

A

Create, store and modify carbohydrates

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7
Q

RER structure

A

Has ribosomes. Sheet like membranes linked to nucleus, form cisternae

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8
Q

RER function

A

Site of protein and glycoprotein synthesis.

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9
Q

Cell wall structure (eukaryotic)

A

Cellulose. Has middle lamella (boundary between two adjacent cells)

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10
Q

Cell wall function

A

Structural support and prevent bursting when undergoing osmosis

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11
Q

Lysosome function

A

Contain digestive enzymes which break down material

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12
Q

Ribosome structure

A

Small granules made of protiens and RNA. 80s and 70s

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13
Q

Ribosome function

A

Site of translation in protein synthesis

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14
Q

Vacuole structure

A

Single membrane sac filled with salts, sugars and AA. Has a tonoplast

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15
Q

Vacuole function

A

Structural support. Store AA and sugars. Pigmented = attract pollinators

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16
Q

Golgi apparatus structure

A

Stack of cristae

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17
Q

Golgi apparatus function

A

Modify proteins received from the ER. Add carbohydrates to form glycoproteins. Then transported in vesicles .

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18
Q

Lysosome structure

A

Formed when GA contains hydrolytic enzymes

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19
Q

What are cristae?

A

Stacks of membranes creating flattened sacs in GA

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20
Q

What are cisternae?

A

Network of tubules and flattened sacs. SER and RER

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21
Q

What is a tonoplast?

A

Membrane around a vacuole

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22
Q

What is a tonoplast?

A

Membrane around a vacuole

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23
Q

Describe the capsule?

A

Slime layer outside cell. Stops it from drying out and sticking together

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24
Q

Describe the cell wall (prokaryotic)

A

Murein

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25
Q

Describe the cell membrane (prokaryotic)

A

Same to eukaryotic - boundary between inside and outside

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26
Q

Describe the flagellum

A

Tail that rotates to move

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27
Q

Describe the nucleoid

A

Single circle of DNA that has genetic materia;

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28
Q

Describe the plasmid

A

Small loops of DNA that contributes to antibiotic resistance

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29
Q

Describe the mesosome

A

Inner folding of cell membrane. Large SA for enzymes used in respiration

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30
Q

Describe the ribosomes (prokaryotic)

A

70s. Not attached to membrane

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31
Q

Describe the ribosomes (prokaryotic)

A

70s. Not attached to membrane

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32
Q

What is homogenisation?

A

Break cell wall in blender and filter to remove debris

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33
Q

What is ultracentifugion?

A

Fractions of filtered homogenate are filtered in tube

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34
Q

3 things the solution needs to be

A

Buffered, ice cold, isotonic

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35
Q

Why does solution need to be buffered?

A

pH is constant so enzymes don’t denature

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36
Q

Why does solution need to be ice cold?

A

Enzymes are slow so don’t destroy organelles

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37
Q

Why does solution need to be isotonic?

A

Prevents osmosis so organelle can’t burst/shrink

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38
Q

Process of cell fractionation

A
  1. Chop up in ice-cold, isotonic and buffered solution
  2. Filter to remove debris
  3. Use centrifuging so most dense forms pellet and suspending organelles form supernatant
  4. Pour into another tube and repeat
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39
Q

Describe the phospholipid bilayer

A

Hydrophobic fatty acid and hydrophilic phosphate group. :) lipid soluble to enter and prevents water soluble substances to enter or leave

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40
Q

Describe the glycolipid

A

Maintain stability, cell recognition and attachment

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41
Q

Describe the glycoprotein

A

Attach to form tissues, cell recognition

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42
Q

Describe the intrinsic protein

A

Carrier and channel proteins

Ions, AA, sugars pass

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43
Q

Describe the extrinsic protein

A

Hormone receptor, cell recognition

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44
Q

Describe cholestrol

A

Control fluidity and prevents water soluble and dissolved ions from leaving

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45
Q

Describe the carbohydrate branch

A

Nothing

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46
Q

Describe the carbohydrate branch

A

Nothing

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47
Q

Define diffusion

A

Net movement of molecules from a high to low concentration down the concentration gradient until evenly distributed

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48
Q

What impacts rate of diffusion?

A

Size, concentration, distance, temperature, SA

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49
Q

How does size impact rate of diffusion?

A

Less KE needed at same temp so move quicker

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50
Q

How does concentration impact rate of diffusion?

A

Bigger conc. gradient = more likely to collide over region

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51
Q

How does distance impact rate of diffusion?

A

Small = time taken to travel is short

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52
Q

How does temperature impact rate of diffusion?

A

More KE = move quicker = more likely to collide

53
Q

How does SA impact rate of diffusion?

A

More space for diffusion = happen faster = more opportunities for collisions

54
Q

Define facilitated diffusion

A

Movement of molecules from a high to low concentration with the use of proteins

55
Q

What molecules can be transported by diffusion?

A

Lipid soluble, non-polar, small, O2, C02

56
Q

What proteins are involved in facilitated diffusion? How?

A

Carrier - large molecules attach and change shape to pass
Channel - form pores and charges particles
Both hydrophilic

57
Q

What molecules can be transported by facilitated diffusion?

A

AA and glucose, water soluble, charged ions

58
Q

What molecules can be transported by facilitated diffusion?

A

AA and glucose, water soluble, charged ions

59
Q

What impacts permeability? (5)

A

Size, lipid soluble, alcohol conc., electrical charge, SA

60
Q

What is the unit for pressure?

A

KSI

61
Q

Water potential of pure water

A

0

62
Q

Define osmosis

A

Movement of water molecules from a highwater potential to an area of low water potential through a selectively permeable membrane.

63
Q

Define active transport

A

Movement of molecules from a high to low concentration by moving against the con. gradient. Involves ATP and carrier proteins

64
Q

Osmosis pratical

A

Potato chip

65
Q

Process of active transport

A
  1. Molecule binds to carrier protein at receptor site
  2. ATP binds to protein at other side which splits (hydrolysis so ADP + phosphate)
  3. protein changes shape and opens at other side
  4. molecule released
  5. ATP reformed and protein reverts to original shape
66
Q

What impacts rate of active transport? (4)

A

Number of carrier proteins, carrier protein speed, rate of respiration

67
Q

Small protein adaptations (4)

A

Big SA, villi, thin epithelial layer, good blood supply

68
Q

Ions involved in co-transport

A

Na+ and K+

69
Q

Process of co-transport

A
  1. C6H12O6and Na+ into epithelial cells (co-trans)
  2. Na+ into blood from epithelial cells and K+ into epithelial cells from blood (act.tra)
  3. C6H12O6 from epithelial cells to blood (f.diffusion)
70
Q

T-cell response name

A

Cell mediated

71
Q

B-cell response name

A

Humoral

72
Q

Two types of defence and examples

A

Specific - T and B cells

Non-specific - phagocytosis, physical barrier

73
Q

3 ways how lymphocytes recognise body cells

A

Foetus (collide w other cells)
Lymph. collide with own material
Survive if receptors for with foreign antigen

74
Q

What is a macrophage?

A

APC that is a WBC

75
Q

What are the 2 types of phagocyte

A

Neutrophil and monocyte

76
Q

What is a neutrophil?

A

Phagocyte - short life span, arrive first and die after engulfing

77
Q

What is a monocyte?

A

Phagocyte - mature to macrophage before engulfing

78
Q

Describe process of phagocytosis

A
  1. Pathogen in blood stream and phagocyte recognises foreign antigens
  2. Receptors bind and engulf
  3. Pathogen enclosed in a phagosome
  4. Phagosome and lysosome fuse
  5. Empty contents into phagosome (hydrolytic enzymes)
  6. Pathogen destroyed and exocytosis happens
79
Q

4 ways how phagocytes are specialised and description

A

Cytoskeleton - change shape to engulf pathogen and move lysosomes
Mitochondria - cell movement and phagocytosis need energy
Ribosomes - Protein synthesis (lysosome enzymes)
Lobed nucleus - enter narrow gaps and change shape

80
Q

Types of T-cells and description

A

Cytotoxic - destroy antigen
Helper 1 - stimulate phagocytosis
Helper 2 - stimulate B-cell production
Memory - remember antigen

81
Q

How T cells work

A

Phagocytosis - WBC presents antigen - fuse with T cells - mitosis

82
Q

What do B cells undergo?

A

Clonal expansion

83
Q

Process of B cell production

A

Phagocyte becomes APC - present antigen to B cell - antigen is complementary to receptor - B cell presents antigen - bind and activate - T-helper cells bind and secrete cytotoxins which stimulates mitosis

84
Q

Types of B cells and description

A

Plasma - secrete antibodies and primary immune response

Memory - if encounter same antigen, divide rapidly to make plasma cells. Secondary response

85
Q

Label an antibody

A 
Light chain - not attached bit
Heavy chain - connected bit
Variable region - top half 
Constant region - bottom half
Antigen binding site - top
Receptor binding site - bottom
86
Q

Bond in an antigen

A

Disulphide bond

87
Q

Antigen bonding to binding site forms a ….

A

Antigen - antibody complex

88
Q

4 functions of antibodies

A

Agglutination, opsonisation, antitoxins, lysis

89
Q

Describe agglutinstion

A

Pathogens are clumeped together

90
Q

Describe oposonisation

A

Pathogens are coated with antibodies

91
Q

Describe antitoxins

A

Toxins produced by pathogen are neutralised

92
Q

Describe lysis

A

Bacteria are destroyed by digestion and rupture bacteria membrane

93
Q

Name the 3 types of immunity

A

Herd, active, passive

94
Q

Describe herd immunity

A

Protection by a viral percentage of population by being vaccinated

95
Q

Describe active immunity

A

Ability to produce own antibodies

96
Q

Describe passive immunity

A

Just receive the antibodies

97
Q

Two methods to get active immunity

A

Natural - after infection

Artificial - Vaccination

98
Q

Two methods to get passive immunity

A

Injection following infection and antibody from mother to foetus

99
Q

4 ways a vaccination program is successful

A

Economical
Few side effects
Stable and easy to store
Easy to administer

100
Q

3 ways a vaccination program is unsuccessful

A

Pathogen frequently mutates
Pathogen hides from immune system
People refuse to be vaccinated

101
Q

Process of being immune by vaccination

A
  1. Pathogen enters body and T/plasma cells made
  2. B and T cells differentiate
    * first exposure and primary response 10-17 days*
  3. Become ill due to slow process
    * Secondary response*
  4. Second exposure to same antigen (2-7 days and higher magnitude/prolonged)
  5. Happens due immunological memory
102
Q

Difference between HIV and AIDS

A 
HIV = pathogen
AIDS = Disease
103
Q

How is HIV transmitted?

A

unprotected sex, birth, sharing needles

104
Q

How does HIV impact the body?

A

Destroy T cells so weak immune response (supressed)

105
Q

Define opportunistic infections

A

Not likely to impact healthy people but causes harm if immune system is supressed

106
Q

Signs and symptoms of AIDS

A
  1. Acute infection - divide rapidly and seed in body (no
    symptoms and inactive)
  2. 2-4 weeks later, flu like symptoms and swollen lymph glands
107
Q

What is the ELISA test?

A

Detect small quantities of proteins (antigens)

108
Q

Name 6 things found in HIV

A

Lipid envelope, matrix, RNA strands, glycoprotein, capsid, reverse transcriptase

109
Q

What is a lipid envelope? (HIV)

A

Lipid bilayer that surrounds virus. Allows to fuse with other membranes

110
Q

What is a matrix? (HIV)

A

Protein layer

Structural support

111
Q

What is a glycoprotein? (HIV)

A

Bind with CD4 on T helper cells - surface protein

112
Q

What is a capsid? (HIV)

A

Protein coat - genetic material and some enzymes

113
Q

What are RNA strands? (HIV)

A

2 - contain al genetic material

114
Q

What is reverse transcriptase? (HIV)

A

Enzymes that catalyse synthesis of rna -> dna

115
Q

3 uses of monoclonal antibodies

A

Pregnancy test, cancer, medical diagnosis

116
Q

How are monoclonal antibodies used in pregnancy tests?

A

HCG produced by placenta binds to MCA and move along strip

117
Q

How are monoclonal antibodies used in cancer treatment?

A

Block chemical signals for growth

118
Q

How are monoclonal antibodies used in medical diagnosis’s?

A

Obtain sample of blood and detect quantity of a substance

119
Q

3 reasons why monoclonal antibodies arent ethical

A

Involve mice
Caused some deaths
Testing has dangers

120
Q

Name 3 types of microscope

A

SEM, TEM OLM (optical light)

121
Q

3 pros of SEM

A

3D
See internal structures
Still fairly high resolution

122
Q

3 cons of SEM

A

Vacuum needed
Staining process
Lower resolution

123
Q

3 pros of TEM

A

Highest resolution - short wave length

Chemical analysis

124
Q

3 cons of TEM

A

2D
Sample destroyed by e-
Need staining process

125
Q

3 pros of light microscope

A

Cheap
Colour
Portable

126
Q

1 con of light microscope

A

Low resolution - long wavelength

127
Q

Why does the nucleus form at the bottom of the test tube in centrifuging?

A

It’s the most dense

128
Q

When a vaccine is given to a person, it leads to the production of antibodies against a disease-causing organism. Describe how.

A
  1. Vaccine contains antigen from pathogen
  2. Macrophage presents antigen on its surface
  3. T cell with complementary receptor protein binds to antigen
  4. T cell stimulates B cell
  5. With complementary antibody on its surface
  6. B cell secretes large amounts of antibody
  7. B cell divides to form clone all producing same antibody

A-Level Biology (7 decks)

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