Chromosome, Genes & DNA Flashcards
Chromosome
3 marks
Genetic structures that usually occur in functional pairs in the nucleus of cells
(except in gametes + bacteria).
Coding strand
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Bases on one strand of DNA used as code for amino acids.
Gene
(7 marks)
- Basic unit of genetic material inherited from parents.
- It is a short length of DNA found on a chromosome that codes for a particular characteristic or protein
- it controls part of a cell’s chemistry - particularly protein production.
Genome
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Complete set of DNA found in an organism.
Nuclei
1 mark
The plural of nucleus.
Organism
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Animal, plant or microorganism.
Chromosomes are thin strands of…
2 marks
DNA (deoxyribonucleic acid).
What are Chromosomes subdivided into?
1 mark
Genes
In most cells where are chromosomes located?
2 marks
In functional pairs in the nucleus.
Number of Chromosomes in Humans
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46 arranged in 23 pairs.
Do not have pairs of chromosomes in their nuclei
1 mark
Gametes
Do not have a nucleus
1 mark
Bacterial cells
The entire genetic material of an organism
1 mark
The genome.
Alleles
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Variations of the same gene.
Example of Alleles
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Eye colour is the gene - blue, green, brown etc. are alleles.
Alleles for brown eyes are
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Dominant
Alleles for blue eyes are
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Recessive
2 Homozygous Brown Eye Alleles
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2 of the Same Dominant Alleles
2 Homozygous Blue Eye Alleles
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2 of the Same Recessive Alleles
2 Heterozygous Alleles
1 mark
2 Different Alleles
DNA molecules are
3 marks
Large + complex - carry the genetic code that determines the characteristics of a living organism.
The backbone of the DNA double helix consists of
3 marks
Alternating phosphate + deoxyribose sugar molecules.
- Interlinking bases hold the 2 sides together.
Four different bases exist in DNA:
4 marks
A = adenine
T = thymine
C = cytosine
G = guanine
Complimentary bases of DNA:
Base-Pairing Simplified
(2 marks)
A - T
C - G
Complimentary bases of DNA:
Base-Pairing Explained
(4 marks)
Adenine - Thymine
Cytosine - Guanine
Base-pairing rule
2 marks
As A is complementary to T + C is complementary to G, they pair up.
A Nucleotide consists of
3 marks
1 phosphate, 1 Deoxyribose sugar + 1 base.
Each individuals DNA is
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Unique
Apart from _________ _____, no one shares the same sequence of bases.
(1 mark)
Identical Twins
Share the same sequence of bases (in DNA)
1 mark
Identical Twins
What do identical twins share?
2 marks
The same sequence of bases (in DNA).
DNA works by
3 marks
Providing a code for cells to make a particular protein (e.g an enzyme).
- This is the DNA Code
The DNA code
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Sequence of bases in DNA.
Where the DNA Code is found
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On the coding strand.
3 bases (in DNA)
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A base triplet.
3 bases (a base triplet) code for
1 mark
1 amino acid.
Amino acids are joined in this order to make the protein
3 marks
A sequence of base triplets (found on the coding strand)
- joined together to make a protein.
The Base Triplet Hypothesis
3 marks
The correct base triplets, arranged in the correct order along the coding strand.
(This is important)
