8th grade cells, genetics and evolution

Question 1

Transport in cells: which statement is true?

• A. Diffusion is faster when the gradient is steeper.
• B. Water moves by osmosis from a concentrated to a dilute solution.
• C. Active transport only happens in plants.
• D. Osmosis needs energy from respiration.

Question 2

Two rabbits from the same litter are fed different diets and grow to different sizes. Why can we not be sure the difference is only due to diet?

• A. The rabbits are clones
• B. Diet never affects size
• C. Brothers and sisters do not have identical genes
• D. Rabbits do not have genes

Question 3

Glucose is absorbed from the small intestine even when the blood already holds more glucose than the gut. How?

• A. by active transport, using energy from respiration
• B. by osmosis
• C. by diffusion down the gradient
• D. it cannot be absorbed

Question 4

Which process is this: urea passing from cells into the blood?

• A. diffusion
• B. osmosis
• C. active transport

Question 5

Exchange surfaces: which statement is NOT true?

• A. Fish gills have many thin filaments to increase surface area.
• B. Villi increase the surface area of the small intestine.
• C. Smaller objects have a larger surface area to volume ratio.
• D. A larger cube has a larger surface area to volume ratio.

Question 6

Human body cells have 23 pairs of chromosomes. How many chromosomes are in an egg cell?

Answer 

Question 7

An organism has the genotype Gg. How is this genotype described?

• A. homozygous dominant
• B. heterozygous
• C. homozygous recessive

Question 8

A virus particle is 20 nm across. What is this in micrometres (µm)? (1 µm = 1000 nm)

Answer µm

Question 9

A cell is 0.1 mm long. How long is it in micrometres (µm)? (1 mm = 1000 µm)

Answer µm

Question 10

Fresh flowers are put in a vase of very salty water. What will happen?

• A. Nothing, because flowers are not alive
• B. They grow faster
• C. They absorb the salt and stay firm
• D. They wilt, because water leaves their cells by osmosis

Question 11

Cuttings from one geranium plant (clones with identical genes) were grown in sun and in shade. Mean height after 8 weeks: sun 52 cm, shade 42 cm. What can you conclude?

• A. The results show light has no effect.
• B. The plants in the shade had different genes.
• C. Height is controlled only by genes.
• D. The difference in height was caused by the environment (light).

Question 12

A cube-shaped cell model has sides of 1 cm. What is its surface area to volume ratio, written as ? : 1?

Answer 

Question 13

What is a gene?

• A. a disease
• B. a type of cell
• C. a whole chromosome
• D. a section of DNA that codes for a protein

Question 14

Which feature does NOT increase the effectiveness of an exchange surface?

• A. a good blood supply
• B. being ventilated
• C. a large surface area
• D. a thick wall