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Biology > TOPIC 2 MARK SCHEME SHIT > Flashcards

TOPIC 2 MARK SCHEME SHIT Flashcards

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1
Q

Why is control strip important when testing for monoclonal antibodies? (2)

A
  1. Prevents false negative results
  2. Shows that the antibody has moved up the strip/not bound to any of the _________
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2
Q

Why are some viruses described as inactive? (2)

A
  1. No more cells infected
  2. because virus isn’t replicating
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3
Q

When mice are injected to make it produce a monoclonal antibody, what should the injection contain?

A

Regulator protein

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4
Q

Give two ways in which pathogens can cause disease

A
  1. Releases toxins
  2. Kills cells/tissues
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5
Q

How to prepare a tissue sample to be observed under a light microscope (4)

A
  1. Add drop of water to glass slide
  2. Obtain thin section of tissue and place on slide/float on drop of water
  3. Stain
  4. Lower cover slip using mounted needle
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6
Q

2 advantages of using a TEM to observe cells

A
  1. High resolution
  2. Can see INTERNAL STRUCTURE of organelles
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7
Q

Describe how the RER is involved in the production of enzymes (2)

A
  1. RER contains RIBOSOMES
  2. to make proteins
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8
Q

Name 4 structures in an eukaryotic cell that CANNOT be identified using an optical microscope

A
  1. Mitochondrion
  2. Ribosome
  3. Endoplasmic reticulum
  4. Lysosome
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9
Q

The events that take place during interphase and mitosis lead to the production of two genetically identical cells. Explain how (4)

A
  1. DNA replicated
  2. Specific/accurate/complementary base-pairing
  3. Two identical/sister chromatids
  4. Each chromatid moves to opposite poles/ends of cell
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10
Q

Describe and explain how cell fractionation and ultracentrifugation can be used to isolate mitochondria from a suspension of animal cells (6)

A
  1. Cell homogenisation to break open cells
  2. Filter to remove large debris/whole cells
  3. Use isotonic solution to prevent damage to organelles
  4. Keep cold to prevent/reduce damage by enzymes / use buffer to prevent protein/enzyme denaturation
  5. Centrifuge at lower speed to separate heavy organelles
  6. Re-spin supernatant at higher speed to get mitochondria in pellet/at bottom
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11
Q

Describe the principles and limitations of using a TEM to investigate cell structure (5)

A
  1. Electrons pass through/enter thin specimen
  2. Denser parts absorb more electrons
  3. So denser parts appear darker
  4. Electrons have shorter wavelength so give high resolution
  5. Can’t look at living material/must be in a vacuum
  6. Specimen must be very thin
  7. Artefacts present
  8. Long preparation time/complex staining method
  9. Only 2D image produced
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12
Q

Outline the role of organelles in the production, transport and release of proteins from eukaryotic cells (4) DO NOT INCLUDE DETAILS OF TRANSCRIPTION & TRANSLATION IN YOUR ANSWER

A
  1. DNA in nucleus is code for protein
  2. Ribosomes/RER produce protein
  3. Mitochondria produce ATP for protein synthesis
  4. Golgi apparatus package/modify
  5. Vesicles transport
  6. Vesicles fuse with cell-surface membrane
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13
Q

Contrast how an optical microscope and a transmission electron
microscope work and contrast the limitations of their use when studying cells. (6)

A
  1. TEM use electrons and optical use light;
  2. TEM allows a greater resolution;
  3. (So with TEM) smaller organelles / named cell structure can be observed
    OR
    greater detail in organelles / named cell structure can be observed;
  4. TEM view only dead / dehydrated specimens and optical (can) view live specimens;
  5. TEM does not show colour and optical (can);
  6. TEM requires thinner specimens;
  7. TEM requires a more complex/time consuming preparation;
  8. TEM focuses using magnets and optical uses (glass) lenses;
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14
Q

Describe binary fission in bacteria (3)

A
  1. Replication of DNA
  2. Replication of plasmids
  3. Division of cytoplasm to produce daughter cells
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15
Q

Evaluation ?s: points AGAINST drug being effective

A
  1. No stats test
  2. Only shows short-term results (over N months)
  3. Only one/two people
  4. Unknown side effects
  5. No control group
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16
Q

Describe how vaccinations can lead to protection against a virus (6)

A
  1. Antigen on surface of virus binds to surface receptor on a specific B cell
  2. Activated B cell divides by mitosis
  3. This is stimulated by T cells
  4. B cells/plasma cells release antibodies
  5. Some B cells become memory cells
  6. Memory cells produce plasma/antibodies faster
17
Q

Describe how a vaccine leads to the production of antibodies against a disease-causing organism (5)

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 which all produce the same antibody
18
Q

Describe difference between active and passive immunity (5)

A
  1. Active involves memory cells, passive doesn’t
  2. Active involves production of antibody by plasma/memory cells
  3. Passive involves antibody being introduced into body from outside
  4. Active long term b/c antibody produced in response to antigen
  5. Passive short term b/c antibody is broken down
  6. Active takes time to develop, passive fast acting
19
Q

What is evidence that an image has been viewed with an optical/light microscope? Explain your answer (1)

A
  1. Need LIGHT to see colour
  2. Can’t see colour with an electron microscope
  3. No organelles are visible
20
Q

The movement of substances across cell membranes is affected by membrane structure. Describe how. (5)

A
  1. Phospholipid bilayer allows movement/diffusion of non-polar/lipid-soluble substances
  2. Phospholipid bilayer prevents movement/diffusion of polar/charged/lipid-insoluble substances
  3. Carrier proteins allow active transport
  4. Channel/carrier proteins allow facilitated diffusion/co-transport
  5. Shape/charge of channel/carrier determines which substances move
  6. Number of channels/carriers determines how much movement
  7. Membrane surface area determines how much diffusion/movement
  8. Cholesterol affects fluidity/rigidity/permeability
21
Q

Describe HIV replication (4)

A
  1. Attachment proteins attach to receptors on helper T cell/lymphocyte;
  2. Nucleic acid/RNA enters cell;
  3. Reverse transcriptase converts RNA to DNA;
  4. Viral protein/capsid/enzymes produced;
  5. Virus (particles) assembled and released (from cell);
22
Q

Describe how a phagocyte destroys a pathogen present in the blood (3)

A
  1. Engulfs;
  2. Forming vesicle/phagosome and fuses with lysosome;
  3. Enzymes digest/hydrolyse;
23
Q

Describe how presentation of a virus antigen leads to the secretion of an antibody against this virus antigen (3)

A
  1. Helper T cell / TH cell binds to the antigen (on the antigenpresenting cell / phagocyte);
  2. This helper T / TH cell stimulates a specific B cell;
  3. B cell clones/divides by mitosis;
  4. (Forms) plasma cells that release antibodies;
24
Q

Organelles involved in protein production/secretion (4)

A
  1. Golgi: package/process proteins
  2. RER/ribosomes: make polypeptide/protein/forming peptide bonds
  3. Mitochondria: release energy/make ATP
  4. Vesicles: secretion/transport of protein
25
Q

Contrast the processes of facilitated diffusion and active transport (3)

A
  1. Facilitated diffusion involves channel or carrier proteins whereas active transport only involves carrier proteins
  2. Facilitated diffusion doesn’t use ATP/is passive whereas active transport uses ATP
  3. Facilitated diffusion takes place down a concentration gradient whereas active transport can occur against a concentration gradient
26
Q

Compare & contrast DNA in eukaryotic cells with DNA in prokaryotic cells (5)

A
  1. Nucleotide structure is identical
  2. Nucleotides joined by phosphodiester bonds
  3. DNA in mitochondria/chloroplasts same/similar to DNA in prokaryotes
  4. Eukaryotic DNA is longER
  5. Eukaryotic DNA contains introns, prokaryotic DNA doesn’t
  6. Eukaryotic DNA is linear, prokaryotic DNA is circular
  7. Eukaryotic DNA is associated with/bound to histones, prokaryotic DNA is not
27
Q

Describe the role of antibodies in producing a positive result in an ELISA test (4)

A
  1. (First) antibody binds/attaches/complementary to antigen
  2. (Second) antibody with enzyme attached is added
  3. (Second) antibody attaches to (first) antibody
  4. (Substrate/solution added and) colour changes
28
Q

Give 3 ways in which DNA in chloroplast is different from DNA in nucleus (3)

A
  1. DNA shorter in chloroplasts
  2. Fewer genes in chloroplasts
  3. DNA circular in chloroplasts
  4. Not associated w/ histones
29
Q

Give the two types of molecule from which a ribosome is made (1)

A

rRNA and protein

Biology (42 decks)

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