CSHS 12 ATAR Biology DNA 2024

In eukaryotes, genes are

• made up of DNA or RNA.

• made up of chromosomes that can be read independently.

• sections of a chromosome that code for a particular trait.

• smaller than DNA but bigger than a chromosome.

Both DNA and RNA are nucleic acids. How else are they similar?

• They both contain deoxyribose.

• They both contain uracil and adenine.

• They are both the same length.

• They both consist of strings of nucleotides.

The amount of the base thymine in a particular sample of DNA was 30%. This means that:

• the amount of guanine was 20%.

  .

• the amount of guanine was 30%.

• the amount of adenine was 20%.

• the amount of adenine was 60%

A sequence of DNA was found to have the following bases: ATT CCG ATC. Which of the following is the correct sequence for the complementary DNA strand?

• UAA GGC UAG

• TAA GGC TAG

• CGG AAT CGA

• ATT CCG ATC

DNA ligase:

• unzips the double helix by breaking the hydrogen bonds between the nucleotides.

• creates bonds between short sections of new DNA, which creates a continuous strand.

• attaches free nucleotides to the replication fork.

• joins DNA polymerase to the replication fork to unwind the parental DNA.

In 2003, the Human Genome Project was completed. The purpose of this project was:

• to see how the DNA of humans was different to the DNA of other organisms.

• to identify the correct sequence of DNA on each chromosome.

• to be able to create DNA fingerprints.

• to be able to replicate the genetic code.

Living things can reproduce sexually or asexually. Which of the following statements is correct about asexual reproduction?

• Small numbers of non-identical offspring are produced by two parents.

• Large numbers of non-identical offspring are produced by a single parent.

• Small numbers of identical offspring are produced by two parents.

• Large numbers of identical offspring are produced by a single parent.

A karyotype can be used to determine:

• the number of chromosomes present in a cell.

• whether recessive traits are present in a cell.

• whether a particular gene is missing from a chromosome.

• whether mutations have occurred in a gene.

In the nucleus of a human liver cell, how many autosomes would there be in total?

• 23

• 22

• 46

• 44

The X and Y chromosomes in humans determine the sex of the individual. They are known as sex chromosomes or:

• heterosomes.

• autosomes.

• homosomes.

• alleles.