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9th grade Meiosis: making egg and sperm cells with half the chromosomes worksheet

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Meiosis: making egg and sperm cells with half the chromosomes

Grade 9 Science Worksheet

NameDate

Circle the best answer.

Read this first
Use this
Fruit fly card (real count: body cells have 8 chromosomes, in 4 matching pairs). One body cell completes meiosis. Cells made: ? Chromosomes in each: ?
1.
Ari reads that a fruit fly body cell has 8 chromosomes. One such cell completes meiosis. What does it make?
- 4 cells, with 4 chromosomes each
- 4 cells, with 8 chromosomes each
- 8 cells, with 2 chromosomes each
- 2 cells, with 4 chromosomes each

Meiosis in a fruit fly, counts per cell (real body-cell count, standard steps)

stage	cells	chromosomes per cell	chromatids per cell
before copying	1 cell	8 chromosomes	8 chromatids
after copying	1 cell	8 chromosomes	16 chromatids
after the first division	2 cells	? chromosomes	? chromatids
after the second division	4 cells	4 chromosomes	4 chromatids

2.
Bo fills in the table for a fruit fly cell. What belongs in the blanks for one cell after the first division?
- 4 chromosomes, 4 chromatids
- 8 chromosomes, 16 chromatids
- 4 chromosomes, 8 chromatids
- 8 chromosomes, 8 chromatids
3.
a fruit fly body cell has 8 chromosomes and completes meiosis. Total chromosomes in all the finished cells together: ? A fruit fly body cell (8 chromosomes) completes meiosis. Esme adds up the chromosomes in all the finished cells together. What is the total?
- 32 chromosomes
- 4 chromosomes
- 16 chromosomes
- 8 chromosomes
4.
Jun reads picture T of a fruit fly cell in the first division. The pairs are being pulled toward the two ends. What goes to each end?
- 8 single chromatids, from splitting each X
- 4 X-shaped chromosomes, one from each pair
- 2 X-shaped chromosomes, from two of the pairs
- 8 X-shaped chromosomes, so both members of each pair
5.
Kira reads cell U, one of the two cells made by the first division of a fruit fly cell. What happens to its chromosomes in the second division?
- Each X splits into 2 chromatids, with 4 going to each end
- Each X stays whole, with 2 X shapes going to each end
- Matching partners part, with 2 chromosomes going to each end
- The 4 X shapes copy their DNA again and then part
Count card (human counts)
Egg cell, 23 chromosomes. Sperm cell, 23 chromosomes. The two cells join to make a new cell (a zygote) with ? chromosomes.
6.
An egg cell and a sperm cell each have 23 chromosomes and join in fertilization. Which description of the new cell does Milo choose?
- 23 chromosomes, one set from the egg cell
- 92 chromosomes, in 46 matching pairs
- 46 chromosomes, in 23 matching pairs
- 46 chromosomes, with the egg cell supplying the whole set
Count card (model data, a model plant)
The new cell formed at fertilization has 10 chromosomes in matching pairs. Chromosomes from the pollen cell: ? Chromosomes from the egg cell: ?
7.
A model plant's new cell has 10 chromosomes after a pollen cell and an egg cell join. Noah traces where they came from. Which is right?
- 4 from the pollen cell and 6 from the egg cell
- 10 from the pollen cell and 10 from the egg cell
- 5 from the pollen cell and 5 from the egg cell
- 10 from the egg cell, which holds the full set
Chromosome cards (model, pairs 1 and 2 are different chromosome pairs)
The parent cell holds 4 cards. Pair 1: a card with A and a card with a. Pair 2: a card with B and a card with b.
8.
A parent cell has chromosome pair 1 with alleles A and a, and pair 2 with B and b. Ren deals the cards for one egg cell. Which cards can go to it?
- A and b
- A, a and B
- A and a
- Aa and Bb
Use this
Pair 1 and pair 2 are different chromosome pairs. The parent cell has pair 1 with A and a, and pair 2 with B and b. Side edge, from the other parent (same alleles): AB, Ab, aB, ab. Top edge: ?
9.
Tala deals cards along the top edge of a Punnett grid. The parent cell has A and a on pair 1, and B and b on pair 2. Which cards go on the edge?
- A, a, B, b as single cards
- Aa and Bb
- AB and ab
- AB, Ab, aB, ab
10.
Zee fills one box of a Punnett grid. The top card is Ab and the side card is aB. Which genotype goes in the box?
- aaBb (A: two small; B: one capital, one small)
- Aabb (A: one capital, one small; B: two small)
- AABB (A: two capital; B: two capital)
- AaBb (A: one capital, one small; B: one capital, one small)

9th grade Meiosis: making egg and sperm cells with half the chromosomes worksheet – printable — Print: 1 2 3 4 5 6

About this worksheet

Meiosis: making egg and sperm cells with half the chromosomes. Every version has 10 questions, and the answer key prints on the second page.

What your child will learn

I can say that a diploid cell (2n) has two matching sets of chromosomes, one set from each parent, and that a haploid cell (n) has one set, as egg and sperm cells do.
I can halve a body-cell number to get the number in an egg or sperm cell (46 to 23 in humans, 8 to 4 in a fruit fly) and double it back to get the body number.
I can say that one cell makes four cells in meiosis, through two divisions in a row after one round of DNA copying, and count the cells and the chromosomes at each step.
I can say that the matching chromosomes part in the first division (meiosis I) and the sister chromatids part in the second (meiosis II), and read this from a labeled picture.
I can count chromosomes (by their joined middles) and sister chromatids in a model cell at each step, using a fruit fly with 2n = 8 as the real case.
I can say that fertilization joins two haploid cells into a diploid zygote, so the body number is restored once and does not double again.

Standard: HS-LS3-1, HS-LS3-2

Words to know

chromosome: One long DNA molecule packed with proteins; it is X-shaped once the DNA is copied

homologous pair: Two matching chromosomes with the same genes, one from each parent

sister chromatids: The two identical copies of one chromosome, joined at the middle

diploid (2n): Having two matching sets of chromosomes, as body cells do

haploid (n): Having one set of chromosomes, as egg and sperm cells do

gamete: A haploid cell that joins another in fertilization: an egg or sperm cell

meiosis: Two divisions in a row that make four haploid cells from one diploid cell

meiosis I: The first division: the matching chromosomes part into two cells

Common mistakes

Your child gave an egg or sperm cell as many chromosomes as a body cell. Egg and sperm cells carry one set, half the body number. Ask your child to halve the body-cell number.

Your child thought meiosis makes two cells. It has two divisions in a row, so one cell makes four. Ask your child to count the divisions, then double twice.

Your child swapped the two divisions. Matching chromosomes part in the first division, and sister chromatids part in the second. Ask your child which division separates the pairs.

Questions parents ask

What is the most common mistake with meiosis: making egg and sperm cells with half the chromosomes?

Your child gave an egg or sperm cell as many chromosomes as a body cell. Egg and sperm cells carry one set, half the body number. Ask your child to halve the body-cell number.

Are these 9th grade science worksheets free to print?

Yes. All 6 printable versions at each level are free to print, with the answer key, and no account is needed.

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9th grade Meiosis: making egg and sperm cells with half the chromosomes worksheet

Use this

Meiosis in a fruit fly, counts per cell (real body-cell count, standard steps)

Count card (human counts)

Count card (model data, a model plant)

Chromosome cards (model, pairs 1 and 2 are different chromosome pairs)