17.2 DNA (Cambridge (CIE) O Level Biology): Flashcards
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- FrontDNA Structure
Define DNA.
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Cards in this collection (24)
Define DNA.
Deoxyribonucleic acid, the molecule that contains the instructions for growth and development of all organisms.
Define gene.
A short length of DNA found on a chromosome that codes for a protein.
Define nucleotide.
The individual unit of DNA, made of a phosphate, a sugar and a base.
What does each gene code for?
A particular sequence of amino acids that make up a protein.
What three parts make up a nucleotide?
A nucleotide is made of:
a phosphate
a deoxyribose sugar
a base
The sequence of in a gene determines the sequence of amino acids in a protein.
The sequence of bases in a gene determines the sequence of amino acids in a protein.
What are the four bases found in DNA?
The four bases are:
adenine (A)
cytosine (C)
thymine (T)
guanine (G)
Give three types of protein coded for by genes.
Examples of proteins include:
structural proteins (e.g. collagen)
enzymes
hormones
In DNA, base A always pairs with .
In DNA, base A always pairs with thymine (T).
Give an example of a structural protein.
Collagen, found in skin cells.
In DNA, base C always pairs with .
In DNA, base C always pairs with guanine (G).
What do proteins determine in an organism?
The characteristics of the organism and the activities of its cells.
DNA is made of two strands wound around each other to form a double .
DNA is made of two strands wound around each other to form a double helix.
Where are genes found?
On chromosomes.
True or False?
In DNA, base A pairs with base G.
False.
A always pairs with T, and C always pairs with G.
Different sequences of amino acids give proteins different and functions.
Different sequences of amino acids give proteins different shapes and functions.
True or False?
DNA is made of two strands.
True.
The two strands are wound around each other in a double helix.
A gene is a short length of found on a chromosome.
A gene is a short length of DNA found on a chromosome.
What forms the 'backbone' of a DNA strand?
The phosphate and sugar of the nucleotides.
True or False?
Genes are made of DNA.
True.
A gene is a short length of DNA on a chromosome.
What does the sequence of bases in DNA code for?
The formation of proteins.
True or False?
A gene codes for a sequence of sugars.
False.
A gene codes for a sequence of amino acids that make up a protein.
Where in the cell is DNA found?
In the nucleus, as part of the chromosomes.
Why do different proteins have different functions?
Because they have different amino acid sequences, which give them different shapes.
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