CAIE Biology: Movement Into & Out of Cells

[Maximum number: 13]

Fig. 1.1 shows the movement of particles through an epithelial cell in the small intestine.

Fig. 1.1

(a)

In Fig. 1.1, arrow P represents the diffusion of oxygen molecules.

[ 3 ]

(i)

Describe what is meant by the term diffusion.

[ 2 ]

(ii)

State the type of energy needed for diffusion.

[ 1 ]

(b)

Carbon dioxide molecules also move by diffusion.

[ 1 ]

(i)

On Fig. 1.1, draw an arrow to show the direction of diffusion of carbon dioxide molecules.

[ 1 ]

(c)

In Fig. 1.1, arrow Q represents another type of particle movement.

Identify the type of particle movement represented by arrow Q.
Explain your answer.
type of movement
explanation

[ 3 ]

(d)

Fig. 1.2 is a photomicrograph of red onion cells.

Fig. 1.2

Fig. 1.3 is a photomicrograph of the same red onion cells after being immersed in a salt solution.

Fig. 1.3

Using Fig． 1.2 and Fig．1．3，describe and explain the difference in appearance of the cells before and after immersion in salt solution．

[ 6 ]

[Maximum number: 1]

Digestive enzymes catalyse the breakdown of large insoluble molecules.

State the name of the substance that is the solvent for most molecules that have been digested by enzymes.

[Maximum number: 3]

Fig. 1.1 shows several villi from the ileum, which is part of the small intestine.

Fig. 1.2 shows the tip of a villus in more detail.

Fig. 1.2

The epithelial cells of the villi absorb nutrients by diffusion and active transport.

Describe how active transport differs from diffusion.

CAIE IGCSE Biology 3 Movement Into & Out of Cells

Covered syllabus points

Covered syllabus points

3. Movement into and out of cells question 1

Question (a)

Question (i)

Question (ii)

Question (b)

Question (i)

Question (c)

Question (d)

3. Movement into and out of cells question 2

3. Movement into and out of cells question 3