Copy of Practice - simple genetics (remote) - Name:Jamila ... - Free Printable

Let’s go step by step through each problem on the worksheet.

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Problem 1: Heterozygous (He) or Homozygous (Ho)

We look at each genotype:

- AA → both alleles same → Ho
- Ee → different alleles → He
- Bb → different → He
- ff → same → Ho
- Pp → different → He
- gg → same → Ho
- Dd → different → He
- HH → same → Ho

✔ All answers in the image are correct.

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Problem 2: Phenotypes from Genotypes

Given:
- Purple (P) dominant to white (p)
- Brown eyes (B) dominant to blue (b)

So:

Flowers:
- PP → purple (dominant trait shows)
- Pp → purple (still has dominant allele)
- pp → white (only recessive)

Eyes:
- BB → brown
- Bb → brown
- bb → blue

✔ All answers in the image are correct.

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Problem 3: Genotypes for Given Phenotypes

Given:
- Straight hair (S) dominant to curly (s)
- Tail spikes (T) dominant to plain tails (t)

For straight hair: can be SS or Ss
For curly hair: only ss

For spikes: TT or Tt
For plain tail: only tt

The image lists:

Straight hair:
→ SS, Ss ✔
Curly: ss ✔

Spikes:
→ Tt, TT ✔
Plain: tt ✔

All correct.

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Problem 4: Punnett Squares

First cross: Tt x tt

Parent 1 gametes: T, t
Parent 2 gametes: t, t

Punnett square:

```
| T | t
---------------------
t | Tt | tt
---------------------
t | Tt | tt
```

Offspring:
- Tt → tall (2 out of 4 = 50%)
- tt → short (2 out of 4 = 50%)

✔ Image says 50% tall, 50% short — CORRECT.

Second cross: Tt x Tt

Gametes: T, t from each parent

Punnett square:

```
| T | t
---------------------
T | TT | Tt
---------------------
t | Tt | tt
```

Offspring:
- TT → tall
- Tt → tall (2 of them)
- tt → short

Total tall: TT + Tt + Tt = 3 out of 4 → 75%
Short: tt = 1 out of 4 → 25%

✔ Image says 75% tall, 25% short — CORRECT.

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Problem 5: Cross homozygous tall with short plant

Homozygous tall = TT
Short = tt (since short is recessive)

Cross: TT x tt

Gametes:
- TT → only T
- tt → only t

All offspring will be Tt

Phenotype: all tall (because T is dominant)

Genotype ratio: 100% Tt
Phenotype ratio: 100% tall

But the question doesn’t ask for percentages — it just sets up the cross. Since no Punnett square or percentage is asked here, and the image stops at stating the cross, we assume this part is incomplete in the image — but based on standard genetics, the answer would be:

→ All offspring are tall (genotype Tt).

However, since the image does not show an answer filled in for #5, and our job is to solve what’s shown — and all previous parts are already correctly answered in the image — we conclude that the student has completed everything correctly so far.

But wait — let’s double-check if Problem 5 was meant to be solved. The instruction says “Complete the Punnett squares...” for #4, and #5 is a new scenario. Since no blank is shown for #5 in the image, perhaps it’s just setting up for next page? But as per instructions, we must solve the task.

Looking again: In the image, under #5, there is NO Punnett square drawn or percentages asked — it just states the cross. So maybe it’s incomplete? But since the user uploaded the full sheet and all other blanks are filled, and #5 has no blank, perhaps it’s just informational?

Actually — re-examining: The image ends at “5. A homozygous tall plant is crossed with a short plant.” and then the website link. There is no space for answer. So likely, this is just introducing the next problem — which isn't shown. Therefore, for the purpose of this assignment, we only need to verify what’s filled in.

And everything filled in is correct.

BUT — hold on! Let me check one more thing.

In Problem 4, second Punnett square (Tt x Tt), the image shows:

Top row: T and t
Left column: T and t

Then inside:

Top-left: TT
Top-right: Tt
Bottom-left: Tt
Bottom-right: tt

That’s correct.

Percentages: 75% tall, 25% short — correct.

Now — is there any error anywhere?

Wait — in Problem 3, for “Tail spikes are dominant to plain tails”, the image lists:

Tt → spikes
TT → spikes
tt → plain

That’s correct.

Also, for straight hair: SS, Ss → straight; ss → curly — correct.

Everything checks out.

Final verification: No calculation errors. All logic follows Mendelian inheritance rules. Dominant traits expressed when at least one dominant allele present. Recessive only when two recessive alleles.

All answers provided in the image are accurate.

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Final Answer:
All answers shown in the worksheet are correct.