Biology 9700/21 — May/June 2013

Cambridge AS Level · worked solutions for every part, with the mark scheme

questions

marks

minutes

Topics Cell Membranes and Transport · Infectious Diseases · Immunity · Transport in Mammals · Cell Structure · Transport in Plants · +4 more

Q1Transport in MammalsCell StructureCell Membranes and TransportFree sample

Capillaries are known as exchange vessels. Substances are exchanged between blood and tissue fluid as the blood flows through the capillaries.

Fig. 1.1 is an electron micrograph of a section through a capillary with two red blood cells.

Fig. 1.1

(a)

(i)

Name the cells labelled A and the structure labelled B.

A ______

B ______

(ii)

Calculate the actual distance X – Y on Fig. 1.1.

Show your working and give your answer to the nearest micrometre ( $\mu\text{m}$ ).

answer = ______ $\mu\text{m}$

(iii)

Explain how capillaries are adapted for their function as exchange vessels.

(b)

Table 1.1 shows the composition of blood, tissue fluid and lymph.

Table 1.1

component	blood	tissue fluid	lymph
red blood cells / $\text{cells mm}^{-3} \times 10^6$	5.1	0.0	0.0
white blood cells / $\text{cells mm}^{-3}$	9 000	75	1 000 000
glucose / $\text{g dm}^{-3}$	800	800	775
protein / $\text{g dm}^{-3}$	71	1	26

Explain the differences between the composition of blood, tissue fluid and lymph as shown in Table 1.1, for white blood cells, glucose and protein.

white blood cells

glucose

protein

(c)

Outline how red blood cells are involved in the transport of carbon dioxide.

The rest of this paper

5 more questions

Q2Infectious Diseases · Immunity6M
Q3Transport in Plants11M
Q4Nucleic Acids and Protein Synthesis · Enzymes · Infectious Diseases · Immunity11M
Q5Cell Membranes and Transport9M
Q6The Mitotic Cell Cycle · Gas Exchange9M

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