7th grade cells, genetics and evolution

Question 1

Why are root hair cells long and thin?

• A. to give a large surface area to absorb water and minerals
• B. to carry sugar
• C. to make food from light
• D. to protect the leaf

Question 2

A cell is 0.1 mm wide. It is viewed at ×400. How wide is the image, in mm?

Answer mm

Question 3

Diffusion: which statement is NOT true?

• A. Diffusion does not need energy from respiration.
• B. A steeper concentration gradient gives faster diffusion.
• C. Diffusion happens in gases and liquids.
• D. Particles stop moving once they are evenly spread.

Question 4

Specialised cells: which statement is true?

• A. All cells in the body look the same.
• B. Sperm cells have no mitochondria.
• C. Root hair cells contain lots of chloroplasts.
• D. Red blood cells have no nucleus.

Question 5

Which specialised cell has a long thin extension for absorbing water?

• A. sperm cell
• B. root hair cell
• C. red blood cell
• D. nerve cell (neurone)

Question 6

Oxygen moves from the alveoli into the blood. Why?

• A. Oxygen is heavier than blood
• B. The heart pushes air in
• C. Blood pulls oxygen like a magnet
• D. There is more oxygen in the alveoli than in the blood

Question 7

Purple dye spread 6 mm through a block of jelly in 2 hours. What was the mean rate of diffusion, in mm per hour?

Answer mm/h

Question 8

An image of a cell is 2 mm wide at ×400. What is the real width of the cell, in micrometres (µm)? (1 mm = 1000 µm)

Answer µm

Question 9

A microscope has a ×5 eyepiece lens and a ×40 objective lens. What is the total magnification?

Answer 

Question 10

What do ciliated cells in the airways do?

• A. absorb food
• B. carry oxygen in the blood
• C. move mucus and trapped dirt away from the lungs
• D. make sperm

Question 11

A cell is 0.05 mm wide. It is viewed at ×100. How wide is the image, in mm?

Answer mm

Question 12

Diffusion: which statement is NOT true?

• A. Particles stop moving once they are evenly spread.
• B. A larger surface area speeds up diffusion.
• C. Diffusion does not need energy from respiration.
• D. Diffusion happens in gases and liquids.

Question 13

Specialised cells: which statement is true?

• A. Red blood cells have no nucleus.
• B. Sperm cells have no mitochondria.
• C. All cells in the body look the same.
• D. Root hair cells contain lots of chloroplasts.

Question 14

Which specialised cell has a tail to swim?

• A. nerve cell (neurone)
• B. sperm cell
• C. root hair cell
• D. palisade cell

Question 15

Oxygen moves from the alveoli into the blood. Why?

• A. Blood pulls oxygen like a magnet
• B. The heart pushes air in
• C. Oxygen is heavier than blood
• D. There is more oxygen in the alveoli than in the blood

Question 16

Purple dye spread 9 mm through a block of jelly in 2 hours. What was the mean rate of diffusion, in mm per hour?

Answer mm/h