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VICBiologyQuick questions
Unit 2: How does inheritance impact on diversity?
Quick questions on Chromosomes, autosomes, sex chromosomes and karyotypes: VCE Biology Unit 2
9short Q&A pairs drawn directly from our worked dot-point answer. For full context and worked exam questions, read the parent dot-point page.
What is chromosome structure?Show answer
A chromosome is one continuous DNA molecule packed with proteins, found in the nucleus of a eukaryotic cell. If stretched out, the DNA in a single human chromosome would be several centimetres long; it has to be packed thousands-of-times tighter to fit into a nucleus a few micrometres across.
What is autosomes and sex chromosomes?Show answer
Human cells contain 46 chromosomes organised as 23 pairs.
What is homologous chromosomes?Show answer
A homologous pair is the two chromosomes in one pair (such as the two copies of chromosome 7, or X and X in a female). They:
What is karyotypes?Show answer
A karyotype is a visual display of all the chromosomes in a cell, arranged by size, banding pattern and centromere position. To prepare one:
What is karyotype notation?Show answer
The convention: total chromosome number, comma, sex chromosomes, comma, any abnormalities.
What is confusing homologous chromosomes with sister chromatids?Show answer
Homologous chromosomes: a pair from two parents, same genes, possibly different alleles. Sister chromatids: two identical copies of one chromosome made by S-phase DNA replication, joined at the centromere.
What is saying the X and Y are "the same"?Show answer
They are not. Y is much smaller, has fewer genes, and pairs with X only at small regions.
What is saying humans have "23 chromosomes"?Show answer
Humans have 46 chromosomes in 23 pairs (somatic cells) and 23 chromosomes (gametes).
What is saying karyotypes show gene mutations?Show answer
Karyotypes show chromosome-level changes (number, large rearrangements). Single-gene mutations are not visible on a karyotype; they need DNA sequencing or PCR.