IGCSE Biology - Chromosomes, genes and proteins (17.1)

Cambridge IGCSE Biology (0610/0970)
Chapter 17 - Inheritance
Topic 17.1 - Chromosomes, genes and proteins
For exams in 2023, 2024 & 2025 (core and extended)

As always this video follows the Cambridge syllabus exactly and contains absolutely everything you need to know for your final exam!

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Timestamps:
0:00 Contents
0:36 Chromosomes, DNA, genes and alleles
1:41 Sex chromosomes
2:16 Base sequences (extended)
3:11 mRNA and protein synthesis (extended)
3:54 Gene expression (extended)
4:24 Haploid and diploid (extended)

Core content:
- State that chromosomes are made of DNA, which contains genetic information in the form of genes.
- Define a gene as a length of DNA that codes for a protein.
- Define an allele as an alternative form of a gene.
- Describe the inheritance of sex in humans with reference to X and Y chromosomes.

Extended content:
- State that the sequence of bases in a gene determines the sequence of amino acids used to make a specific protein (knowledge of the details of nucleotide structure is not required).
- Explain that different sequences of amino acids give different shapes to protein molecules.
- Explain that DNA controls cell function by controlling the production of proteins, including enzymes, membrane carriers and receptors for neurotransmitters.
- Explain how a protein is made, limited to:
• the gene coding for the protein remains in the nucleus
• messenger RNA (mRNA) is a copy of a gene
• mRNA molecules are made in the nucleus and move to the cytoplasm
• the mRNA passes through ribosomes
• the ribosome assembles amino acids into protein molecules
• the specific sequence of amino acids is determined by the sequence of bases in the mRNA (knowledge of the details of transcription or translation is not required).
- Explain that most body cells in an organism contain the same genes, but many genes in a particular cell are not expressed because the cell only makes the specific proteins it needs.
- Describe a haploid nucleus as a nucleus containing a single set of chromosomes.
- Describe a diploid nucleus as a nucleus containing two sets of chromosomes.
- State that in a diploid cell, there is a pair of each type of chromosome and in a human diploid cell there are 23 pairs.

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[ihprobe]

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[lolo]

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[Ikshitdad]

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