Biology 9700 · AS & A Level · Homeostasis in mammals
Homeostasis in mammals — practice question
Adipose tissue is a specialised connective tissue whose main role is to act as the body’s principal storage tissue in the form of triglycerides. In humans, there are two forms of adipose tissue: white adipose tissue (WAT) and brown adipose tissue (BAT). WAT is the more abundant type and is located beneath the skin and around some internal organs. BAT occurs in infants around the back and shoulders. In adults, BAT is present too, but in much smaller amounts. BAT cells contain a greater number of mitochondria than WAT cells. BAT helps to keep blood temperature constant when the outside environment is cold.
(a(i))[4]
The human body keeps blood temperature steady through a process called homeostasis. Referring to blood temperature, outline the main principles of homeostasis.
(a(ii))[2]
Suggest why infants have proportionally more BAT than adults.
(b(i))[2]
Name the structures A and B shown in Fig. 8.1.
(b(ii))[1]
Draw an arrow on Fig. 8.1 to show the direction of the proton gradient between the matrix and the intermembrane space.
(b(iii))[1]
State the two processes shown in Fig. 8.1 that become more active during periods of cold external conditions.
(b(iv))[1]
State the by-product produced as a result of processes 1 and 2.
(b(v))[1]
Suggest the main respiratory substrate for BAT cells.
Worked solution & mark scheme
This 12-mark question has a full step-by-step worked solution and mark scheme. One marking point: “temperature changes are detected by receptors/hypothalamus” …