Exchange

Surface area to volume ratio decreases as the organism gets...

Bigger

1 of 48

Organisms with a high SA/vol ratio need a ***** metabolic rate/respire faster to maintain body temperature

Higher

2 of 48

Spiracles close to conserve...

Water

3 of 48

Spiracles open when the ***** reaches a certain level

Carbon dioxide

4 of 48

Water moves out of the trachioles because lactic acid...

Lowers the water potential in the muscle fibres

5 of 48

A countercurrent means that...

The concentration gradient is maintained along the whole length of the lamellae

6 of 48

Stomata close at night to conserve...

Water

7 of 48

Thick cuticles, rolled leaves, hairy leaves, stomata in pits, leaves with small surface area... (what happens to the water potential?)

Reduce the water potential gradient

8 of 48

Explain what happens when you inhale

Diaphragm contracts and moves down, ribs move up and out (external intercostal muscles contract). Volume increases pressure falls

9 of 48

Explain what happens when you exhale

Diaphragm springs back to dome shape, ribs move down and in (internal intercostal muscles contract). Volume decreases pressure increases

10 of 48

Tidal volume is the...

The volume of air breathed in each breath

11 of 48

Pulmonary ventilation = ****** x ******

Tidal volume x ventilation rate

12 of 48

Red cells **** **** in lung capillaries and are flattened against the wall of the capillary - **** time for gaseous exchange

Red cells slow down in lung capillaries and are flattened against the wall of the capillary - more time for gaseous exchange

13 of 48

Amylase changes starch to...

Maltose

14 of 48

Where do endopeptidases break polypeptide chains?

In the middle

15 of 48

Where do exopeptidases break polypeptides?

At the terminal or penultimate bond

16 of 48

What does lipase do?

Makes fatty acids and glycerol

17 of 48

What does bile do?

Emulsifies fat and neutralises acid

18 of 48

Where is amylase produced?

The mouth and pancreas

19 of 48

Where are proteases (peptidases) produced?

The stomach and pancreas. They are also bound to the wall of the small intestine

20 of 48

Where are maltase, sucrase and lactase found?

In the wall of the small intestine

21 of 48

Fat molecules are reformed from monoglycerides and fatty acids in the SER and enter the lacteal via

Chylomicrons

22 of 48

Glucose enters the intestinal cells by

Co-transport with sodium ions

23 of 48

How many chains does haemoglobin have?

Four polypeptide chains

24 of 48

The curve is S shaped because when the first O2 binds, it changes the shape of the Hb so molecules two and three find it ***** to bind. As the Hb becomes saturated, it gets ****** for the final O2 to bind

Easier, harder

25 of 48

The pattern for the dissociation curve is...

Left to load, right to release

26 of 48

Carbon dioxide shifts the curve to the...

Right

27 of 48

What happens when pressure in ventricle > pressure in atrium?

AV valves shut

28 of 48

What happens when pressure in ventricle > pressure in arteries?

Semi-lunar valves open

29 of 48

Explain the cardiac cycle

Atria contract/ventricles relax, ventricles contract/atria relax, ventricles and atria relax

30 of 48

Cardiac output =

stroke volume x heart rate

31 of 48

Contract = ****** relax = ******

Systole, diastole

32 of 48

What am I? Muscle for vasoconstriction, elastic tissue to stretch and recoil to even out pressure, smooth endothelium to allow blood to flow

Artery

33 of 48

What am I? Large lumen to allow blood to flow, valves to prevent backflow, thin walls because there is little pressure to withstand

Vein

34 of 48

What does tissue fluid do?

Supplies the cells with water, glucose, amino acids, fatty acids and O2. It receives CO2 and urea from the cells

35 of 48

Soluble proteins are too **** to be squeezed out. They remain in the capillary and **** the water potential, so fluid returns by **** at the end. Excess fluid drains into vessels (as osmosis isn't sufficient to reabsorb it all)

Large, lower, osmosis

36 of 48

Hydrostatic pressure ***** as fluid is lost and friction

Falls

37 of 48

Water is drawn up the **** in a continuous colum called the **** stream

Xylem, transpiration

38 of 48

The transpiration stream is driven by ****** from the leaves

Evaporation

39 of 48

Water molecules are attached to each other through *****. They make ****** bonds with each other

Cohesion, hydrogen

40 of 48

Water molecules also ***** to the walls of the xylem vessles. The colum of water is under *****. This makes the trunk get ******

Adhere, tension, narrower

41 of 48

Xylem vessels are ***** and don't have end walls. They are coated with *****

Hollow, lignin

42 of 48

***** transports organic molecules e.g. sugar, growth factors around the plant. This is called ***** and occurs in ******

Phloem, translocation, sieve tubes

43 of 48

Sugar moves down a concentration gradient into the ****** H+ ions are actively transported from companion cells into spaces in cell wall H+ ions and sucrose are co-transported into ******

Companion cells, sieve tubes

44 of 48

Water enters the sieve tubes from the **** by *****, creating ***** pressure

Xylem, osmosis, hydrostatic

45 of 48

At respiring cells, sugar is used up or converted into *****. Sucrose is ****** transported into them from sieve tubes, ***** their water potential

Starch, actively, lowering

46 of 48

**** moves from sieve cells to respiring cells by osmosis, ***** the water potential of the sieve cell. There is now more ***** pressure in the first sieve tube, which will cause the mass flow of sucrose solution

Water, lowering, hydrostatic

47 of 48

***** experiments and experiments involving ***** tracers demonstrate that sugar travels in the *****

Ringing, radioactive, phloem

48 of 48

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