B3 Series

Compared to a single-celled amoeba, a multicellular rabbit has:

• a smaller surface area to volume ratio, making gas exchange less efficient

• a larger surface area to volume ratio, making gas exchange more efficient

• the same surface area to volume ratio as an amoeba

• no need for specialized respiratory structures

The function of the secretion of surfactant in the alveoli is to:

• Reduce surface tension and prevent alveolar collapse

• Increase the thickness of the alveolar wall

• Promote the absorption of oxygen into the blood

• Cause the alveoli to fill with fluid

A spirometer is used for:

• measuring lung capacity

• monitoring heart rate

• testing blood sugar levels

• measuring blood pressure

A leaf is prevented from desiccating in the hot sun by:

• the cuticle

• chlorophyll

• stomata

• xylem

Which three environmental factors would lead to a relatively high rate of transpiration?

• High temperature, low humidity, strong wind

• Low temperature, high humidity, no wind

• Low temperature, low humidity, weak wind

• High temperature, high humidity, no wind

The Bohr shift refers to:

• the decrease in hemoglobin's affinity for oxygen due to lower pH or higher CO2 levels

• the increase in hemoglobin's affinity for oxygen at higher altitudes

• the movement of electrons between energy levels in an atom

• the process by which oxygen is converted to carbon dioxide in the lungs

Suggest a reason why the Bohr shift is particularly important when you are exercising strenuously.

• Because it helps more oxygen to be released to the muscles during strenuous exercise.

• Because it reduces the amount of carbon dioxide produced during exercise.

• Because it increases the heart rate during exercise.

• Because it prevents lactic acid buildup in the muscles during exercise.

• Due to the shape of the haemoglobin molecule it is difficult for the first oxygen molecule to bind to its haem group

• However, after the first oxygen molecule binds, the haemoglobin protein changes shape, or conformation, making it easier for the next oxygen molecules to bind

  • This is known as ____________ binding.

A plot of fetal haemoglobin shows a curve that is to the left of the mother’s curve when both are plotted together on an oxygen dissociation curve. What does this mean and why is it important

• It means the mother’s haemoglobin binds oxygen more tightly than the foetal haemoglobin.

• It means foetal haemoglobin has a lower affinity for oxygen, making oxygen transfer less efficient.

• It means both haemoglobins have the same affinity for oxygen, so there is no difference in oxygen transfer.

• It means foetal haemoglobin has a higher affinity for oxygen, allowing efficient transfer of oxygen from mother to foetus..

It is incorrect to say that high fat diets cause heart attacks because:

• Heart attacks are caused by multiple factors, not just high fat diets.

• All fats are equally harmful to the heart.

• High fat diets always lead to heart attacks in everyone.

• Heart attacks are only caused by high cholesterol foods.