B1 Cell Structure & Transport

Question 1

What part of a cell controls the passage of substances into and out of the cell?

Answer 1

Cell membrane

Question 2

What part of a plant cell strengthens the cell?

Answer 2

Cell wall

Question 3

Where do most of the chemical reactions take place in the cell?

Answer 3

Cytoplasm

Question 4

Where in the cell are the genes found?

Answer 4

In the nucleus in chromosomes

Question 5

Give four differences between an animal cell and the cell of a bacterium

Answer 5

1. A bacterium has no nucleus
2. A bacterium has a cell wall
3. A bacterium does not have mitochondria
4. A bacterium has just one chromosome

Question 6

Oxygen moves into a cell by the process of…

Answer 6

diffusion.

Question 7

Water moves into a cell by the process of…

Answer 7

osmosis.

Question 8

In order to have a high rate of diffusion there must be a large c_____ g_____.

Answer 8

concentration gradient.

Question 9

What is a concentration gradient?

Answer 9

How rapidly the concentration of a chemical changes from one place to another.

Question 10

If you place a potato cube in pure water why does it gain mass?

Answer 10

Water enters the potato’s cells by osmosis because the concentration of water outside the cells is higher than inside the cells.

Question 11

If you place a potato cube in a very concentrated salt solution why does it lose mass.

Answer 11

Water leaves the potato’s cells by osmosis because the concentration of water outside the cells is lower than inside the cells.

Question 12

If you place a potato cube in a salt solution and it does not change mass what does this mean?

Answer 12

It means the concentration of water must be the same inside the potato’s cells as outside the cells in the solution.

Question 13

How can you tell a cell is an animal cell not a plant cell? Give three reasons.

Answer 13

1. No cell wall
2. No large vacuole
3. No chloroplasts

Question 14

If there is a higher concentration of oxygen outside a cell than inside, which way will oxygen diffuse?

Answer 14

Into the cell.

down the concentration gradient

Question 15

Scientists call a group of similar cells ____.

Complete the sentence with:
an organ / a system / a tissue

Answer 15

a tissue

Question 16

What is osmosis?

Answer 16

The diffusion of water from high water concentration (more dilute) to low water concentration (less dilute) across a semi-permeable membrane.

Note: a high water concentration means a dilute solution, i.e. a low concentration of any solute dissolved in it.

Question 17

What is diffusion?

Answer 17

The random movement of a chemical from an area of high concentration to low concentration. Does not require energy.

Question 18

What is active transport?

Answer 18

The movement of a chemical from an area of low concentration to high concentration. Requires an energy input.

Question 19

Where might active transport take place in plants?

Answer 19

In the root hair cells, as there is a higher concentration of minerals inside the root hair cells than outside in the soil.