Unit 2 Flashcards Preview

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Flashcards in Unit 2 Deck (29)
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1
Q

Describe how antibodies are produced in the body following a viral infection (6)

A
  • Virus contains antigen
  • Virus is engulfed by macrophage
  • presents antigen to B-cell
  • B-cell divides by mitosis
  • Plasma cells produce antibodies
  • Specific to antigen
2
Q

Describe how HIV is replicated after it has entered a human cell (4)

A
  • Reverse Transcriptase uses HIV RNA to make DNA copy
  • DNA used to make HIV RNA copies
  • and HIV proteins made at host ribosomes
  • Budding off from membrane of host cell
3
Q

What is a vaccine? (1)

A

A small dosage of antigens to stimulate production of antibodies

4
Q

Give two ways in which pathogens can cause disease when they enter the body of their host (2)

A
  • Damage cells/tissues

- Produce toxins

5
Q

Phagocytes and Lysosomes are involved in destroying microorganisms. Describe how (3)

A
  • Phagocytes engulf pathogens
  • enclosed in a vaccine
  • lysosomes have enzymes
  • that digest molecules
6
Q

Describe how B-lymphocytes respond when they are stimulated by antigens (4)

A
  • Divide by mitosis
  • to produce plasma cells
  • plasma cells produce antibodies
  • and memory cells
7
Q

Describe the role of macrophages in stimulating B-lymphocytes (1)

A
  • The antigen in membrane is presented to lymphocytes
8
Q

The destruction of T-cells by HIV leads to the death of an infected person. Explain how (2)

A
  • Not enough T-cells to produce antibodies

- Person cannot fight infections

9
Q

Give two factors other than cost that should be considered when selecting an antibiotic to treat a bacterial disease (2)

A
  • Side effects

- How much resistance the bacteria have built up

10
Q

Name the process by which bacterial cells divide (1)

A

Binary fission

11
Q

Describe how the Golgi apparatus is involved in the secretion of enzymes (1)

A

The golgi apparatus modifies the protein

12
Q

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

A
  • RER has ribosomes to make proteins (like an enzyme)
13
Q

Describe how you could use cell fractionation to isolate chloroplasts from the leaf tissue (3)

A
  • Homogenisation by grinding up the cells in a blender in a cold, isotonic, buffered solution
  • Remove debris by filtration
  • 2nd pellet formed from ultracentrifugation (has the chloroplast)
14
Q

Name the structures in a eukaryotic cell that cannot be identified using an optical microscope (2)

A
  • mitochondria
  • ribosome
  • E.R.
  • lysosome
15
Q

Describe how phospholipids are arranged in a plasma membrane (2)

A
  • Phospholipids are arranged in a bilayer
  • Hydrophobic tails face inside
  • Hydrophilic head faces outside
16
Q

Explain why a person with mitochondrial disease can only exercise for a short time (2)

A
  • They cannot produce much ATP if they have damaged mitochondria
  • The ATP is needed for muscle contraction
17
Q

Explain why a transmission electron microscope was used to produce the image in the figure above (2)

A
  • High resolution

- Can see the internal structure of organelles

18
Q

In coaliac disease, microvilli in epithelial cells are damaged. Explain why people with coaliac disease have low concentrations of amino acids in their blood (2)

A
  • Damaged microvilli means they have less surface area of absorption
  • due to less protein channels
  • less amino acids are absorbed
19
Q

Name the type of bond that joins amino acids together in a polypeptide (1)

A

Peptide

20
Q

Describe the function of a chloroplast (2)

A
  • The site of aerobic respiration

- Release ATP for active transport

21
Q

Why can electron microscopes produce an image with higher resolution than optical microscopes? (1)

A
  • Electrons have shorter wavelengths than light
22
Q

Describe how you could make a temporary mount of a piece of plant tissue to observe the position of starch grains in the cells when using an optical microscope (4)

A
  • Add a drop of water to the slide
  • Obtain a thin section of plant tissue and place on the slide
  • stain with iodine in potassium iodide
  • Lower coverslip using a mounted needle
23
Q

Explain why it is important that the plant tissue was thin (or 1-cell thick) (1)

A

To allow light to pass through so it can be seen by an optical microscope

24
Q

What do both Eukaryotic and Prokaryotic cells have?

A
  • Plasma membrane
  • Cytoplasm
  • Ribsomes
  • DNA and RNA
25
Q

What do Eukaryotic cells have that Prokaryotic cells don’t?

A
  • Nucleus
  • Mitochondria
  • ER
  • Golgi Body
26
Q

What do Prokaryotic cells have that Eukaryotic cells don’t?

A
  • Plasmids
  • Flagella
  • Protective waxy cuticle
27
Q

How do Eukaryotic cells divide?

A

Mitosis

28
Q

What is a virus?

A

Acellular, non-living particles

29
Q

What do viruses contain?

A
  • Nucleic acids (DNA/RNA)
  • Capsid (protein coat)
  • (don’t have cytoplasm, nucleus, membrane-bound organelles, plasma membrane)