Chromosomes, genes and proteins
Introduced| English | Meaning |
|---|---|
| chromosomes/ˈkrəʊməsəʊmz/ | Structures made of DNA and associated proteins that carry genetic information. |
| gene/dʒiːn/ | A DNA sequence that contributes to a functional product, such as a protein or RNA molecule. |
| DNA/ˌdiː en ˈeɪ/ | DNA |
| protein/ˈprəʊtiːn/ | A biological macromolecule made of one or more folded chains of amino acids. |
| characteristics/ˌkærɪktəˈrɪstɪks/ | Features or qualities that describe or distinguish an organism, object or group. |
The instructions inside you
- Every cell carries a complete set of instructions for building and running your body.
- These instructions are stored in chromosomes 染色体, genes 基因 and DNA 脱氧核糖核酸.
A gene is:
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A gene codes for one protein.
Chromosomes are made of a molecule called ______.
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DNA stores the genetic code.
Chromosomes and genes
- Chromosomes are long threads of DNA, found in the nucleus.
- A gene is a section of DNA that codes for one protein 蛋白质.
A chromosome is made of DNA and carries genes; a gene is a length of the DNA
From gene to protein
Step along the DNA template: each base pairs to an mRNA base, and every three bases (a codon) codes for one amino acid in the protein.
How many chromosomes are in a human body cell?
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Body cells have 46 chromosomes (23 pairs).
How many chromosomes are in a human gamete?
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Gametes have half — 23 — so fertilisation restores 46.
How many chromosomes
- Human body cells have 46 chromosomes (23 pairs).
- Gametes have 23 — half the number — so fertilisation restores 46.
A human karyotype: 23 pairs of chromosomes, ending in XY for a male
Genes control characteristics by coding for:
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Proteins (like enzymes) build and run the body.
Genes control proteins
- Genes code for proteins, and proteins build and run the body (e.g. enzymes).
- So genes, through the proteins they make, control your characteristics 特征.
Gene, chromosome and DNA are not the same. DNA is the molecule; a chromosome is a long coiled length of it; a gene is a short section of that DNA coding for one protein. They nest inside each other.
mRNA copies a gene, then a ribosome reads it to build a protein from amino acids
You've got it
- chromosomes are threads of DNA in the nucleus; a gene is a section coding for one protein
- human body cells have 46 chromosomes; gametes have 23
- genes control characteristics through the proteins they code for