chapter 6 exam questions

Question 1

Explain how the ventilation mechanism of a fish and the structure of its gills result in the
efficient uptake of oxygen from water (6)

Answer 1

-many fillaments and lamellae creates large surface area
-thin epithilium creates short diffusion pathway
-large no of capilleries maintains steep concentration gradient
–countercurrent flow maintains a steep concentration gradient across the entire length of the gill lamellae.

Question 2

A rise in the temperature of water decreases the amount of oxygen dissolved in the water.
As the water temperature rises, the rate of ventilation in a fish also rises. Explain the
advantage of this. (2)

Answer 2

provides same amount of oxygen
need to hav emore water flowing over the gills

Question 3

When first hatched, the young of some species of fish are less than 2 mm long.

Explain how these young fish get enough oxygen to their cells without having gills.(2)

Answer 3

exchange across body surface
short diffusion pathway

Question 5

describe the path of a molecule of oxygen fromm their air in the alveolus at x to the plasma membrance of cell x (1)

Answer 5

capillery endothilium/alveolar epithilum

Question 6

Cell A is a eukaryotic cell. Give two features that may be foundd in a prokaryotic cell which are not found in cell a (2)

Answer 6

plasmids
capsule
flagellum

Question 7

explain how the relationship between the direction of flow of water and of blood shown in the micrograph is useful to a fish (3)

Answer 7

-blood and water flow in opposite directions
-more oxygen diffuses into blood
-more respiration

Question 8

suggest a method you could use to estimate the concentraation of glucose in several differnet solutions taht all turned brickj red with benedict’s reagent in 3 minutes (1)

Answer 8

time how long it takes to go brick red