7th grade cells, genetics and evolution

Question 1

A cell is 0.02 mm wide. It is viewed at ×400. How wide is the image, in mm?

Answer mm

Question 2

Which change would make diffusion faster?

• A. a lower temperature
• B. a thicker membrane
• C. a smaller surface area
• D. a higher temperature

Question 3

Agar cubes containing indicator were put into acid. Time for the whole cube to change colour: 1 cm cube 6 min, 2 cm cube 12 min, 3 cm cube 24 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 4

An image of a cell is 10 mm wide at ×200. What is the real width of the cell, in micrometres (µm)? (1 mm = 1000 µm)

Answer µm

Question 5

A microscope has a ×10 eyepiece lens and a ×4 objective lens. What is the total magnification?

Answer 

Question 6

Which specialised cell has branched endings to connect to many cells?

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

Question 7

Diffusion: which statement is NOT true?

• A. Diffusion happens in gases and liquids.
• B. Diffusion moves particles from low to high concentration.
• C. A larger surface area speeds up diffusion.
• D. A steeper concentration gradient gives faster diffusion.

Question 8

Specialised cells: which statement is true?

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

Question 9

Why do muscle cells contain many mitochondria?

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

Question 10

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

Answer mm

Question 11

Someone opens a bottle of perfume in one corner of a still room. Soon it is smelled everywhere. Why?

• A. The perfume becomes a solid
• B. Air particles stop moving
• C. Perfume particles are pulled by gravity
• D. Perfume particles diffuse from high to low concentration

Question 12

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 24 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 13

An image of a cell is 4 mm wide at ×400. What is the real width of the cell, in micrometres (µm)? (1 mm = 1000 µm)

Answer µm

Question 14

A microscope has a ×10 eyepiece lens and a ×100 objective lens. What is the total magnification?

Answer 

Question 15

Which specialised cell is a biconcave disc to carry oxygen?

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

Question 16

Diffusion: which statement is NOT true?

• A. A larger surface area speeds up diffusion.
• B. Diffusion stops completely when the room is cold.
• C. Diffusion does not need energy from respiration.
• D. Diffusion happens in gases and liquids.