Biology topic 4 Flashcards

1
Q

What is endocytosis

A

Cell extensions called pilli engulf material to form vesicles and enter the cytoplasm

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2
Q

What is exocytosis?

A

The vesicle fuses with cell membrane and release contents from the cell.

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3
Q

Role of exo/endocytosis

A

To move large molecules across the cell membrane

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4
Q

Role of ATP in active transport

A

Binds to carrier protein to provide it with energy for protein to change shape and carry substances in and out of the cell

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5
Q

How is ATP energy released

A

When ADP is phosphorylated to ATP, energy is generated. When ATP is hydrolysed the energy is released

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6
Q

What happens to haemoglobin affinity for oxygen and saturation when partial pressure increases

A

Haemoglobins affinity for oxygen increases, saturation increases

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7
Q

What happens to haemoglobin affinity for oxygen and saturation when partial pressure decreases

A

Haemoglobins affinity for oxygen decreases, saturation decreases

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8
Q

What factors affect haemoglobins affinity for oxygen?

A

Partial pressure of oxygen and carbon dioxide

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9
Q

What effect does increased partial pressure of CO2 have on haemogobins affinity for O2

A

Presence of CO2 causes haemo’s affinity for O2 to decrease
Oxygen released, dissociates from haemo to be used in repairing tissues (Bohr effect)

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10
Q

How many polypeptide chains does haemoglobin contain?

A

4 polypeptide chains

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11
Q

How many polypeptide chains does myoglobin contain?

A

1 polypeptide chain

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12
Q

Function of haemoglobin

A

Transport oxygen

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13
Q

Function of myoglobin

A

Store oxygen

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14
Q

Dissociation curves S shape

A

Due to cooperative binding of O2
After one O2 molecule binds, the shape of haemoglobin changes making it easier for other oxygen molecules to bind (steep part)
As haemo becomes highly saturated, harder for oxygen to bind (graph plateaus)

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15
Q

Bohr effect

A

Curve shifts to the right due to increased CO2
Lowers pH causing haemo to change shape
Reduces affinity for O2
Increased O2 unloading in respiring tissues used for respiration.

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16
Q

Dissociation curve shifts to the left?

A

Increased affinity
Increased loading in the lungs at lower O2
Good for organisms at high altitude

17
Q

Dissociation curve shifts to the right

A

Decreased affinity
Increased unloading in respiring tissues
Good for organisms with high metabolic rate

18
Q

Definition of hydrostatic pressure

A

Residual pressure from the heartbeat
Higher at arterial end of capillary

19
Q

Definition of oncotic pressure

A

Movement of fluid out of capillaries due to hydrostatic pressure
Water potential of capillaries become more -ve

20
Q

Features of the xylem

A

Transport of water and minerals
Dead cells, long cylinders with open ends to form continuous columns
Pits- Allows water to move sideways
Lignin- Structure and flexibility to structure

21
Q

Features of the phloem

A

Living cells
Movements of nutrients to storage, organs, and growing parts
Sieve tube elements- Form tube to transport sugars
Companion cells- ATP production, for active processes
Cytoplasm linked by plasmodesmata- gaps between cell walls allowing flow between cells

22
Q

Symplast pathway (xylem)

A

Water moves through cytoplasm via plasmodesmata

23
Q

Apoplast pathway (xylem)

A

Water moves through cell walls and intercellular spaces that are permeable

24
Q

Affect of air movement on transpiration

A

Increased air movement- increased transpiration
Removes still air around leaf
Increases conc gradient and diffusion rate

25
Q

Affect of humidity on transpiration

A

Increased humidity- decreased transpiration
Decreases conc gradient and diffusion rate

26
Q

Affect of temperature on transpiration

A

Increase temp- increases random motion, increases rate of evaporation- increases rate of transpiration
Warmer air holds more water vapour

27
Q

Light intensity on transpiration

A

Increased light intensity- increased transpiration
Increases no of stomata open for gas exchange
Plateaus when all stomata open

28
Q

Mass flow hypothesis summary

A
  1. Sugar loaded into sieve tubes via active transport
  2. Lowers H2O potential, H2O to move in from xylem
  3. Hydrostatic pressure cause sugars to move
29
Q

Function of plasma

A

Transport nutrients, hormones, excretory products etc
Transfer heat around body

30
Q

Function of erythrocytes

A

Red blood cells
Transport O2
Biconcave shape + lack of nucleus
Contain haemoglobin

31
Q

Different types of leukocytes

A

Leukocytes- White blood cells
Neutrophils- Phagocytosis
Basophils- Histamine, inflammatory/allergic rxn
Eosinophils- Parasites, allergic, inflammatory, immunity

32
Q

2 types of agranulocytes

A

Monocytes
Lymphocytes

33
Q

Blood clotting process

A
  1. Platelets attach to exposed collagen fibres
  2. Thromboplastin (protein) released from platelets. Trigger inactive prothrombin to active thrombin (enzyme)
    Ca2+ and vit K present
  3. Thrombin catalyses conversion of soluble fibrinogen to insoluble fibrin
  4. Fibrin- network of fibres traps contents to form blood clot.
34
Q

How is tissue fluid formed

A

Formed from blood plasma
Hydrostatic pressure, moves out of the capillaries

35
Q

Function of tissue fluid

A

Provides nutrients to cells
Removes waste products

36
Q

What happens to the tissue fluid not reabsorbed?

A

Enters lymphatic system
Prevents swelling due to water retention
Formed lymph —> removes waste products
Lymph returns to the subclavian vein