genes y11 1st yopic

Question 1

allele

Answer 1

a version of a gene, cause differences in inherited characteristics

Question 2

codon

Answer 2

sequence of three bases on an amino acid , each codon codes to a particular amino acid

Question 3

diploid

Answer 3

cell that contains two sets of chromosomes

Question 4

dna structure

Answer 4

nucleotide is mad up of a nitrogenous base (e.g. adenine), a phosphate group and a deoxyribose sugar
link via a bond between phosphate group of one nucleotide and the deoxyribose of another
strands line up in an antiparralel way
bases of one strand will joing by hydrogen bonds with the bases of the antiparralel strand in a complementary way.

Question 5

how many types of codon are there and how many amino acids are there

Answer 5

because there are 4 types of bases 64 types of codon, there are 20 amino acids meaning that some codons code for the same amino acid

Question 6

what is transcription

Answer 6

proteins are made in the cell cytoplasm by cytoplasm, dna is found in nucleus and is therefore too big to get out of the cell.
rna binds to a non coding DNA in front of the gene
two dna strands unzip rna polymerase moves along strands
rna uses coding dna in the gene as a template to make the rna,, base pairings occur so that mRNA is complementary to gene, once made mRNA molecule moves out of nucleus and bonds with a cytoplasm.

Question 7

what is translation

Answer 7

it is the changing of mRNA to a polypeptide, this happens at the ribosome, this forms complementary base pairings with tRNA anticodons
amino acids are brought to ribosome by another rna molecule,
order in which amino acids are brought to match codon.
part of trna structure is called in an anticodon, complementary to codon, codon + anticodon makes sure that they are complementary

Question 8

sex determinisation

Answer 8

XX = woman
XY= man

Question 9

mitosis key answer

Answer 9

diploid cell with 2 sets of 1 chromosome
each chromosome duplicates to form x shaped chromosome
chromosome line up along the equator of the cell.
spindle fibres attach to the chromosome and pull the duplicates apart, the two parts of the chromosome go to opposite sides of the cell.

Question 10

meiosis

Answer 10

diploid cells with two sets of two chromosomes chromosomes become short and fat before meiosis.
each chromosome duplicates to form an x shape chromosome. They become twice as big.
chromosomes line up along the equator
spindle fibres attach to the chromosome and pull the pairs apart.
the cytoplasm splits into two to form two new cells
they then split again.

Question 11

coding

Answer 11

dna controls the production of proteins
proteins made of chains of molecules named amino acid
amino acid folds up to give each protein specific shape, meaning they have a different function
each amino acid is coded for by a particular amino acid
64 possible codons
aminno acids make proteins

Question 12

amino acid

Question 13

what detemines characteristic of the protein

Answer 13

shape

Question 14

difference between dna mrna trna

Answer 14

polynucleotide strands 2/2/1

shape double helix/ straight single stranded/ clover

Question 15

sugar

Answer 15

deoxyribose/ ribose/ ribose