7th grade cells, genetics and evolution

Question 1

A cell is 0.02 mm wide. It is viewed at ×200. How wide is the image, in mm?

Answer mm

Question 2

Which specialised cell has many mitochondria for energy to swim?

• A. sperm cell
• B. red blood cell
• C. palisade cell
• D. root hair cell

Question 3

An image of a cell is 25 mm wide at ×500. What is the real width of the cell, in micrometres (µm)? (1 mm = 1000 µm)

Answer µm

Question 4

Diffusion: which statement is NOT true?

• A. A larger surface area speeds up diffusion.
• B. A steeper concentration gradient gives faster diffusion.
• C. Diffusion happens in gases and liquids.
• D. Diffusion stops completely when the room is cold.

Question 5

Why do muscle cells contain many mitochondria?

• A. to store water
• B. to carry oxygen
• C. to release lots of energy for contraction
• D. to make chlorophyll

Question 6

A microscope has a ×15 eyepiece lens and a ×4 objective lens. What is the total magnification?

Answer 

Question 7

Specialised cells: which statement is true?

• A. Stem cells can develop into many different types of cell.
• B. All cells in the body look the same.
• C. Sperm cells have no mitochondria.
• D. Root hair cells contain lots of chloroplasts.

Question 8

Oxygen moves from the alveoli into the blood. Why?

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

Question 9

Agar cubes containing indicator were put into acid. Time for the whole cube to change colour: 1 cm cube 8 min, 2 cm cube 12 min, 3 cm cube 18 min. Which cube's centre was reached fastest by the acid?

• A. the 1 cm cube
• B. the 2 cm cube
• C. the 3 cm cube

Question 10

A cell is 0.05 mm wide. It is viewed at ×400. How wide is the image, in mm?

Answer mm

Question 11

Which specialised cell has no chloroplasts because it is underground?

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

Question 12

An image of a cell is 0.8 mm wide at ×100. What is the real width of the cell, in micrometres (µm)? (1 mm = 1000 µm)

Answer µm

Question 13

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 happens in gases and liquids.
• D. A steeper concentration gradient gives faster diffusion.

Question 14

Why are root hair cells long and thin?

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

Question 15

A microscope has a ×10 eyepiece lens and a ×10 objective lens. What is the total magnification?

Answer 

Question 16

Specialised cells: which statement is true?

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