9th grade cells, genetics and evolution

Question 1

What is the probability (in %) that a baby will be biologically male (XY)?

Answer %

Question 2

Which type of division makes egg and sperm cells?

• A. meiosis
• B. fertilisation
• C. mitosis
• D. binary fission

Question 3

A human enzyme has an optimum temperature of about 37 °C. What is the enzyme most likely to be doing at 37 °C?

• A. working slowly, but not denatured
• B. working at or near its fastest rate
• C. denatured and no longer working

Question 4

Why must DNA be copied during interphase?

• A. To halve the chromosome number
• B. To make gametes
• C. So each new cell gets a full, identical set of chromosomes
• D. So the cell can photosynthesise

Question 5

A bacterium divides into two every 30 minutes. Starting with one cell, how many cells are there after 3 hours (if none die)?

Answer 

Question 6

Where is this found: plasmids (small rings of DNA)?

• A. prokaryotic cells only
• B. eukaryotic cells only
• C. both types of cell

Question 7

A fruit fly sperm cell has 4 chromosomes. It fertilises an egg cell from the same species. How many chromosomes does the zygote (fertilised egg) have?

Answer 

Question 8

A gene on the X chromosome causes red–green colour blindness. Why is it more common in XY people?

• A. XY people have two X chromosomes
• B. The Y chromosome causes colour blindness
• C. They have only one X, so one recessive allele is enough to show the condition
• D. It is caught from other people

Question 9

What is an advantage of sexual reproduction?

• A. It produces variation, which helps a species survive changes
• B. It needs only one parent
• C. It is faster than asexual reproduction
• D. It makes identical offspring

Question 10

In a root tip slide, 200 cells were counted. 50 of them were dividing. The cell cycle takes 20 hours. Estimate how long mitosis lasts, in hours.

Answer h

Question 11

Which organism is made of prokaryotic cells?

• A. yeast
• B. a mushroom
• C. an amoeba
• D. E. coli bacteria

Question 12

Prokaryotes and eukaryotes: which statement is NOT true?

• A. Eukaryotic cells keep their DNA inside a nucleus.
• B. Bacterial cells are much smaller than most animal and plant cells.
• C. Plant cells are prokaryotic.
• D. Both prokaryotic and eukaryotic cells have ribosomes.

Question 13

Sex chromosomes: which statement is NOT true?

• A. The egg cell decides whether a baby is XX or XY.
• B. Human body cells contain one pair of sex chromosomes.
• C. The chance of a baby being XY is about 50 % for each pregnancy.
• D. Every human egg cell carries an X chromosome.

Question 14

Mitosis or meiosis? It used for growth and repair.

• A. mitosis
• B. meiosis

Question 15

Where are stem cells found in a plant?

• A. in the leaf veins only
• B. in meristems at the tips of roots and shoots
• C. only in the flowers
• D. in the xylem vessels