Mendel's laws of segregation and independent assortment
Grade 9 Science Worksheet - Building Confidence
Circle the best answer.
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Table
A pea cross in four boxes (model), 4 rows. Columns: box, plants shown. Row 1: W, the two true-breeding parent plants, one with violet flowers and one with white flowers. Row 2: X, the offspring of those two parent plants. Row 3: Y, the offspring of two box X plants crossed together. Row 4: Z, the offspring of two box Y plants crossed together.
Ari labels a pea cross with boxes W, X, Y and Z. Which box shows the F2 generation?
- Box W: the two plants crossed first
- Box Y: the offspring of two box X plants
- Box X: the first offspring of the parents
- Box Z: the offspring of two box Y plants
Two pea lines (model)
plant line offspring when crossed with itself violet-flowered line violet flowers in each generation white-flowered line white flowers in each generation Bo reads that Mendel started with true-breeding pea plants. What does true-breeding mean?
- They carry a violet and a white allele, so they give both colors
- They have two recessive alleles, so they show the recessive trait
- Crossed with themselves, they always give offspring that look like them
- They are a mix of two lines, so their flowers show a pale blend
Mendel's real F1 results (real data: Mendel)
characteristic plants crossed (P) F1 offspring seed texture round × wrinkled 100 percent round seed color yellow × green 100 percent yellow flower color violet × white 100 percent violet Esme reads Mendel's F1 results. What did the F1 seeds show when round plants were crossed with wrinkled plants?
- All round, because round is the dominant trait
- Slightly bumpy, because the two shapes blend
- Half round and half wrinkled, because each trait gets a turn
- All wrinkled, because the wrinkled allele wins
Jun fills a Punnett square for pea seed shape. Which genotype goes in the blank box?
- r (one wrinkled allele)
- RR (two round alleles)
- rr (two wrinkled alleles)
- Rr (one round, one wrinkled allele)
Kira fills a Punnett square for pea plant height. Which genotype goes in the blank box?
- TT (two tall alleles)
- tt (two dwarf alleles)
- Tt (one tall, one dwarf allele)
- T (one tall allele)
Luz reads a filled Punnett square for seed color. How many of the four boxes show a plant with yellow seeds?
- 2 boxes
- 3 boxes: YY, Yy and Yy
- 1 box
- 4 boxes, since both parents have a Y
Milo sees each box of the grid take one allele from each parent. Which idea explains this?
- Dominance: one allele hides the other allele
- Segregation: the two alleles of a gene separate
- Independent assortment: different genes are passed on separately
- Blending: the two alleles mix into one allele
One plant, two genes (model)
gene plant's alleles where the gene sits flower color Vv one chromosome plant height Tt a different chromosome Noah reads a card about two genes on different chromosomes. Which idea says they are passed on separately?
- Blending: the two genes mix into one trait
- Dominance: one gene hides the other gene
- Independent assortment: the two genes are passed on separately
- Segregation: the two alleles of a gene separate
Mendel's real counts, seed shape (real data: Mendel)
generation what the plants showed F1 100 percent round F2 5,474 round and 1,850 wrinkled Tala reads Mendel's seed-shape counts. What does the table show about wrinkled seeds?
- Back in the F2 with 5,474 seeds, more than round
- Present in the F1 and the F2
- Missing in the F1, back in the F2
- Gone for good after the F1
Mendel's real counts, seed color (real data: Mendel)
generation what the plants showed F1 100 percent yellow F2 6,022 yellow and 2,001 green Zee adds up Mendel's F2 seed-color counts. How many seeds did Mendel count in the F2?
- 2,001 seeds
- 6,022 seeds
- 8,023 seeds
- 4,021 seeds