Ngā Whāinga Ako 🔗
- Understand the relationship between cells, nuclei, chromosomes, genes, alleles and DNA.
- Understand the role DNA plays in carrying instructions to the next generation and determining phenotype.
Think, pair and share what do you know about DNA, genes, chromosomes, cells, nucleus, organisms and can you put them in order of magnitude?
What are we made of? 🔗
Organisms are made of cells, each cell contains a nucleus, the nucleus contains chromosomes made up of DNA, and DNA contains many genes.
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Cells 🔗
All organisms on Earth are made of one or more cells
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Nucleus 🔗
Inside each cell is a nucleus. The nucleus holds genome of the cell in the form of chromosomes.
Chromosomes 🔗
Chromosomes are located inside the nucleus and are made up of long chains of DNA. Humans have 23 pairs of chromosomes, giving us 46 in total!
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Deoxyribonucleic Acid (DNA) 🔗
DNA is a very long chain of base pairs which forms chromosomes.
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Genes 🔗
A gene is a small segment of DNA made of base pairs and are what determine everything about us! Each chromosome carries many genes. Humans have around 25000 genes. That is a lot of genes per chromosome!
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Alleles 🔗
Each gene has two alleles, one allele comes from each parent. E.g. brown hair from mum, blonde from dad.
Mahi Tuatahi: Review! 🔗
Discuss with the people around you and create a diagram relating cells, nuclei, DNA, chromosomes, DNA and alleles to each other. Try and do it without using your notes (but look if you need to!).
Allele 🔗
A gene has two alleles: one from each parent. The allele is on a chromosome and we call two chromosomes of the same shape a homologous pair.
Homozygous and Heterozygous 🔗
If you have two of the same allele (e.g. brown and brown) this is homozygous. If you have different alleles (e.g. brown and blue) this is heterozygous.
Structure of DNA 🔗
:::notes Adenine, cytosine, guanine, thymine. As with Ts and Gs with Cs. :::
- We call this complementary base pairing.
- Which bases pair with which bases and what are they called? Label them on your diagram!
Questions 🔗
Answer question 1 and 2 on page 9 of your sciPAD.
Exercise: Building DNA! 🔗
on sciPAD pages 8-9, cut out the DNA pieces and build some DNA and stick it on the previous page!
Look to page 10 for a hint!