7.4 Genes & Proteins Flashcards
Alleles are…
An alternative form of a gene
Human DNA is arranged in the form of…
23 pairs chromosomes
We receive one set of chromosomes from our father and the other from our…
Mother
Diploid is a cell, nucleus or organism in which the nuclei contain…
Two copies of each chromosome - 46
Haploid is a cell, nucleus or organism in which the nuclei contains…
Just one set of chromosomes - 23
Each cell has…
Homologous pairs of chromosomes
A gene is…
A section of DNA that carries coded information about a characteristic
Genes occur at the same relative position or…
Locus on homologous chromosomes
These paired chromosomes are not completely identical, but they…
Carry the same genes
Each of the homologous pair of chromosomes has a different allele for eye colour from the other, in this way, genes influence the…
Phenotype or characteristics of an organism
Phenotype is…
The characteristics of an organism resulting from its alleles
The allele that codes for cystic fibrosis has…
3 nucleotides missing - codon, anticodon
These 3 nucleotides code for one amino acid
The CF allele produces a protein that is exactly the same as the normal protein except for one…
Amino acid which is significant
Proteins form a…
Complex tertiary structure - bonds form between R groups in the amino acids that hold the protein in this specific tertiary structure
The faulty CFTR protein produced by the CF allele is a different shape because just one…
Amino acid is missing - cannot function properly
Many genes code for proteins that act as…
Enzymes
The shape of the active site depends on the tertiary structure of the protein which in turn depends on the…
Order of the amino acids - which is dependant on the sequence of bases in the DNA molecule
Different alleles have slightly different…
Base sequences in the DNA - this means that they produce a protein with a slightly different sequence of amino acids and so the enzyme has a different tertiary structure.
This means that the enzymes may have an…
Altered active site and so cannot form an ESC with its substrate anymore
Garrod studied…
Alkaptonuria
People with this disorder cannot break down a substance called…
Homogentisic acid
Homogentisic acid accumulates in the…
Tissues and is excreted in urine
It is detected easily because the …
Molecule oxidises into a black product which means that the urine is dark in colour
The black product also accumulates in places such as…
The sclera of the eye and the cartilage of the ear and nose
