5.3 Genes and alleles

• Biologie
• Middelbare school
• vwo
• Leerjaar 2

5.3 DNA and genes

DNA

DO YOU REMEMBER?

nucleotides (base of DNA)

4 different bases (nucleotides)

cytosine

guanine

adenine

thymine

double helix (ladder)

information is stored in code

AATCCGGACGAATTCCGGAAAAAATTTTTTTTTTTTTTTTTTCGCGCGAATTCATATATATCGGACGGACGAAC etc etc etc it would be a very thick book :-)

GENE: section of DNA with complete code for a protein

proteins

Lots of functions

E.g. enzymes, hormones, antibodies, cell structure

gene = code for 1 protein

Genes determine your characteristics

copying

you start with one fertilised egg with 46 chromosomes...

you end up with billions of cells with the same 46 chromosomes => all of them a copy from the original.....

things can go wrong on the way => mutations (5.5)

from DNA code to proteins

3 bases = 1 amino acid

ACC is code for one type

AAG is code for another

21 different amino acids.

string of amino acids = protein

amino acids -> protein

The molecule
shown in the
picture is called ...

1. DNA
2. single stranded DNA
3. an amino acid
4. a ribosome

This is a picture of ..

1. chromosome
2. gene
3. DNA
4. cell

Below are a few codes with 4 letters.
Which of these codes show a piece ofDNA?

1. ABCDBDCA
2. CAEFEAFC
3. GACTATGC
4. TACDDTAC

What do you call the part of a chromosome that carries the information for 1 heriditary trait?

1. DNA
2. a gene
3. a mother cell
4. an egg cell

Does the information for hereditary traits change when a cell is copied?

1. yes
2. no

this is a picture of ........

1. cell
2. chromosome
3. DNA
4. gene

Practice

Read paragraph 5.3

do 5.3 exercises 1,2,4,5,78,