DNA

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  • Created by: Natalie
  • Created on: 10-04-13 16:01
What does a nucleotide consist of?
Deoxyribose, Phosphate group and Organic base
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What bonds are formed between the sugar and the phosphate?
Strong covalent bonds
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What holds two polypeptide strands together?
Weak hydrogen bonds
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How does the sugar phosphate backbone help?
It gives the molecule strength (due to covalent bonds)
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How does coiling of the DNA molecule help it to carry out its function?
It allows long molecules to be compacted into a small space.
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Why do the weak hydrogen bonds allow DNA to carry out its function?
They are broken easily, so unzipped easily for replication.
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Why does having lots of hydrogen bonds allows the DNA to carry out its function?
As the cumulative effect increases the stability of DNA.
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How does the sequence of bases assist the DNA molecule to carry out its function?
It allpws lots of info to be stored.
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Why does the length of the DNA molecule help it to carry out its function?
It allows lots of info to be stored.
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Why does the use of complementary base pairing help DNA to carry out its function?
It can be replicated by complementary base pairing.
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Why does the double helix structure enable the DNA molecule to carry out its function?
It protects the weak hydrogen bonds, so is more stable.
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What is a gene?
A section of DNA that contains coded info for making polypeptides to make proteins.
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How does altering the sequence of amino acids affect a protein?
Alters the primary structure which therefore affects the tertiary structure and overall shape of the protein.
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How many bases are present in DNA?
Cytosine, Guanine, Adenine and Thymine.
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How many bases code for one amino acid?
3 (produces 64 codes, enough to produce 20 amino acids). A codon.
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What is a degenerate code?
When each amino acid has 2-6 triplets coding for it.
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What are stop codons?
triplet codes which do not code for an amino acid.
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What is an intron?
DNA which does not code for amino acids, occurs within a gene or as multiple repeats.
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What is an exon?
part of a base sequence that codes for amino acids.
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What is an allele?
An alternate form of a gene, base sequence of a gene has undergone a mutation
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What are mutations in genes caused by?
UV light. nuclear radiation and mistakes when cell copies its DNA.
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Explain the mutation of Substitution.
Replacement of a nucleotide with another containing a different base.
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Explain the mutation of Deletion.
loss of a nucleotide.
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Explain the mutation of Addition.
Addition of a nucleotide.
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What is point mutation?
change in the base sequence of the DNA of a gene.
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How does substitution/inversion affect the DNA?
alters half of the DNA codons and half of the amino acids in proteins.
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How does deletion/insertion affect the DNA?
shift in the whole sequence of bases, all codons changed after this point, frame shift, different primary structure, damaging.
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How is the DNA in a prokaryotic cell different to a eukaryotic cell?
no nucleus, DNA linear, DNA located in nucleoid, genome contains fewer genes, no membrane bound organelles, DNA not associated with histones, not organised into chromosomes, DNA organises into one circular molecule and plasmids.
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What is a chromosome?
Structure formed from a long DNA molecule wrapped around histone proteins by which hereditary material is passed from one generation to another.
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What are histone proteins?
small proteins rich in amino acids, lysine and arginine, DNA is bound to them.
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What is chromatin?
It is condensed into chromosomes, visible in non-dividing cells.
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What is the name of the stain used to make chromosomes visible?
Accetic orcein.
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What is a karyotype?
total chromosome completement.
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What is the centromere?
central region of the chromosome, divides chromosome into two parts, one short, one long. Helps control movement of chromosomes, important in cell division.
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What are the telomeres?
ends of chromosomes, DNA and protein, maintains the integrity of DNA by sealing ends of the linear molecule.
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What are homologous chromosomes?
matching pairs of chromosomes, one chromosome derived from mother, one from father to form diploid number.
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What are the autosomes?
Chromosomes not involved with determining sex.
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What are hetrosomes?
X and Y chromosomes involved in determining sex.
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What is the diploid number?
normal two sets of chromosomes in cells. 2n
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What is the haploid number?
only have one chromosome of each pair, half diploid number in cells (gametes)
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Other cards in this set

Card 2

Front

What bonds are formed between the sugar and the phosphate?

Back

Strong covalent bonds

Card 3

Front

What holds two polypeptide strands together?

Back

Preview of the front of card 3

Card 4

Front

How does the sugar phosphate backbone help?

Back

Preview of the front of card 4

Card 5

Front

How does coiling of the DNA molecule help it to carry out its function?

Back

Preview of the front of card 5
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Swallowtail

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A  thought provoking set of flashcards which would enable students to either learn the key definitions found when learning about DNA or to test themselves by downloading the cards and printing them off.

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