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All 9 Flashcards — Karyograms, DNA profiling & variation
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Question
What is a karyogram?
Answer
A chart of a cell's chromosomes **arranged in homologous pairs by size** (and banding pattern).
Question
What three things can a karyogram tell you?
Answer
The **chromosome number**, the **sex** (XX/XY), and whether any chromosome is **extra or missing**.
Question
How do you read the SEX from a human karyogram?
Answer
Look at the **last (23rd) pair**: **XX = female**, **XY = male** (a large X next to a small Y).
Question
How would you compare another species' karyogram with a human one?
Answer
Compare the **chromosome number**, the **relative sizes** of the chromosomes, and the **banding pattern**.
Question
What is a DNA profile (DNA fingerprint)?
Answer
A pattern of **DNA bands** that is almost **unique to an individual**, used to identify people and their relatives.
Question
State the golden rule for reading a parentage DNA profile.
Answer
**Every band in the child must match a band in one of its two parents** — a candidate missing a band is ruled out.
Question
How do you identify a father from a paternity DNA profile?
Answer
Remove the bands the child shares with the **mother**; the **true father must have all the remaining bands**.
Question
Name three ways sexual reproduction generates variation.
Answer
**Crossing over** and **independent assortment** in meiosis, plus **random fertilisation**.
Question
Why is every offspring (except identical twins) genetically unique?
Answer
Meiosis makes genetically different **gametes**, and **random fertilisation** combines two of them into a new mix of alleles.
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Topic 4.8 hub
Inheritance
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