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Y12 BTEC - Unit 1 - Bio > B2 > Flashcards

B2 Flashcards

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1
Q

What are the features of a palisade mesophyll cell that make it optimal for photosynthesis?

A
  1. Cells are elongated and cylindrical with many closely packed together to increase surface area to absorb as much light as possible.
  2. Contains many chloroplasts, which contains chlorophyll, to trap/absorb sunlight energy.
  3. Chloroplasts are moved by the cytoskeleton (proteins which can attach onto organelles and support the cell) upwards to absorb more sunlight OR downwards to prevent damage from too intense light.
  4. A large permanent vacuole pushes chloroplasts to the outer edges of the cell. This increases the light energy they absorb and reduces the diffusion distance for CO2 into the chloroplast.
  5. A large permanent vacuole also makes the cell turgid, stores water and dissolved substances from photosynthesis.
  6. Thin and transparent cellulose cell walls so easy gas diffusion. This also allows light energy, needed for photosynthesis, to penetrate.
  7. The plasma membrane is selectively permeable, it allows diffusion of CO2 and H2O (reactants) into the cell and allows O2 and glucose out of the cell (products).
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2
Q

What is the importance of the chloroplasts inside a palisade cell?

A
  1. Chloroplasts contain chlorophyll.
  2. Chlorophyll traps light energy.
  3. They are the site of the chemical reaction, photosynthesis.
  4. Sunlight is converted into chemical energy as CO2 is converted to glucose
    (see equation above).
  5. Glucose is then available for respiration.
  6. Can also result in the production of starch/sucrose/ lipids/amino acids/DNA/cellulose/vitamins which enables cellular growth.
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3
Q

Explain how the vacuole in a palisade mesophyll cell helps to increase the rate of photosynthesis.

A
  1. Vacuole is large so takes up a lot of space
  2. This pushes the chloroplasts to the edge of the cell
  3. They therefore receive more light energy
  4. There is also a shorter diffusion distance for diffusion
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4
Q

What organelles in a palisade mesophyll cell give it a rigid structure?

A

Vacuole and cell wall

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5
Q

What is labelled A in the diagram?

A

Head

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6
Q

What is labelled B in the diagram?

A

Acrosome

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7
Q

What is labelled C in the diagram?

A

Cell membrane

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8
Q

What is labelled D in the diagram?

A

Nucleus

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9
Q

What is labelled E in the diagram?

A

Mitochondria

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10
Q

What is labelled F in the diagram?

A

Tail/Flagellum

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11
Q

Why does a sperm cell contain many mitochondria?

A

Produce large amounts of ATP via aerobic respiration to provide energy for motility

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12
Q

What does the acrosome contain in a sperm cell?

A

Digestive enzymes

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13
Q

Why do sperm cells require enzymes?

A

To digest the zona pellucida of the egg cell

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14
Q

What is labelled A in the diagram?

A

Corona radiata

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15
Q

What is labelled B in the diagram?

A

Nucleus

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16
Q

What is labelled C in the diagram?

A

Cytoplasm

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17
Q

What is labelled D in the diagram?

A

Zona pelluccida

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18
Q

Why is it important that the cytoplasm in an egg cell have a large volume?

A

contain lots of nutrients, lots of organelles and many mitochondria to supply large quantities of ATP for cell division, protein synthesis and DNA replication

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19
Q

What is the function of the zona pellucida?

A

Act as a thick transparent protective layer around the egg cell

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20
Q

What is the function of the corona radiata?

A

Supply protein to the fertilised egg

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21
Q

What will a fertilised egg cell need to do to become an embryo?

A

Divide by mitosis

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22
Q

What changes happen to the egg cell upon fertilisation?

A
  1. The zona pellucida will harden becoming impermeable to any other sperm cells.
  2. This prevents more than one sperm cell entering the egg cell (called polyspermy).
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23
Q

Are gametes (sperm and egg cells) haploid or diploid?

A

Haploid

24
Q

Explain why root hair cells have long “hair like” projections.

A

Increase surface area to increase the rate of absorption of water and ions

25
Q

What is the function of the plasma membrane in a root hair cell?

A

contains specific carrier and channel proteins to allow ions to cross into the cytoplasm by diffusion or active transport

26
Q

What does active transport need to happen?

A

ATP made in aerobic respiration in the mitochondria

27
Q

Which organelle makes ATP?

A

Mitochondria

28
Q

What process makes ATP?

A

Respiration

29
Q

How is a root hair cell specialised to carry out a lot of active transport of mineral ions?

A

Contains many mitochondria

30
Q

How is the cell wall of the root hair cell specialised?

A

It is think allowing a short diffusion pathway increasing the rate of diffusion of ions and water

31
Q

Why does a root hair cell contain no chloroplasts?

A

More room for absorbed water and ions. Hidden from light so can’t photosynthesise

32
Q

Name the cell pictured

A

Root hair cell

33
Q

Draw and label a root hair cell

A
34
Q

Give an example of a foreign particle that might be recognised by a white blood cell triggering an immune response.

A

Virus, bacteria, fungi, pollen, transplanted cell

35
Q

What are the two main types of lymphocyte?

A

T lymphocytes and B lymphocytes

36
Q

What does a B lymphocyte produce?

A

Antibodies that are specific to the pathogen which will lead to its destruction

37
Q

What happens to a B lymphocyte when it recognises a pathogen?

A
  1. Divides by mitosis to make lots of identical cells
  2. Some will become plasma cells
  3. Plasma cells release lots of a specific antibody into the blood
  4. Some cells become memory cells
38
Q

What do memory cells do?

A

Remain in the blood stream in case the same type of pathogen enters the body again to give a more rapid response to produce more antibodies faster

39
Q

How do vaccines work?

A

They contain part of a pathogen and encourage B lymphocytes to produce antibodies and memory cells

40
Q

What is the role of a helper T lymphocyte?

A

Send chemical signals to the B lymphocytes stimulating the B lymphocytes to divide by mitosis

41
Q

What type of white blood cell can directly destroy cancer cells or infected body cells?

A

T lymphocyte

42
Q

Describe the shape of the nucleus of a neutrophil

A

Lobed

43
Q

Why does a neutrophil have a lobed shaped nucleus?

A

It makes the neutrophil flexible so they can easily squeeze between the cells that make up the capillary wall to move to the site of infection

44
Q

Describe the importance of lysosomes in a neutrophil

A
  1. Neutrophils contain many lysosomes.
  2. Lysosomes fuse with engulfed pathogen (called the phagosome) to form a phagolysosme.
  3. Lysosomes contain enzymes which destroy pathogens or foreign substances which have been engulfed by the neutrophil.
  4. This process is called phagocytosis.
45
Q

What type of cell is pictured here?

A

Neutrophil

46
Q

What are the similarities between lymphocytes and neutrophils?

A
  1. Both cells have nuclei/mitochondria/RER/ribosomes.
  2. Both cells are made from stem cells that are in the bone marrow (of long bones).
  3. Both are transported in blood plasma, migrate to tissue fluid and are present in the lymphatic system to provide defense against pathogens.
47
Q

What are the differences between lymphocytes and neutrophils?

A
  1. There are 3x as many neutrophils as T and B lymphocytes combined.
  2. T and B cells have a large nucleus and are smaller than neutrophils.
  3. Neutrophils have a lobed nucleus which makes the cell flexible and able to squeeze through the capillary wall. Lymphocytes cannot do this and remain in the blood.
  4. They have antigen receptors on its cell surface membrane which can bind to antigens on a pathogen whereas a neutrophil does not.
  5. T and B cells are part of the adaptive and specific immune response whereas neutrophils are only involved in innate immunity.
  6. T and B cells have immunological memory whereas neutrophils do not.
  7. B cells produce antibodies and become memory cells (when stimulated by T helper cells) whereas neutrophils only involved in phagocytosis.
  8. Neutrophils contain many lysosomes for phagocytosis whereas lymphocytes have less lysosomes.
  9. Cytotoxic T cells destroy virally infected and cancerous cells whereas neutrophils do not.
48
Q

What is the role of the red blood cell?

A

To carry oxygen from the lungs to the respiring tissues for aerobic respiration

49
Q

What molecule in a red blood cell binds to oxygen?

A

Haemoglobin

50
Q

What type of cell has no organelles?

A

Red blood cell

51
Q

Why does a red blood cell contain no organelles?

A

Increase space for haemoglobin to give more efficient transport of oxygen and carbon dioxide

52
Q

What shape are red blood cells?

A

Biconcave

53
Q

Why are red blood cells small?

A

To squeeze through capillaries

54
Q

Explain why red blood cells have a biconcave shape?

A

Increase surface area to volume ratio so that:
1. Haemoglobin molecules are close to the cell membrane
2. short diffusion distance of oxygen to haemoglobin
3. Increase rage of diffusion across plasma membrane

55
Q

What feature of red blood cells makes them flexible?

A

Biconcave shape

56
Q
A

Y12 BTEC - Unit 1 - Bio (3 decks)

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