Unit 1 Gene Expression Flashcards
Define Gene
Gene is a DNA sequence that codes for a protein
Define Genotype
Genotype is the genetic makeup of an organism
Define phenotype
Phenotype is the physical appearance of an organism
Name the units that make up an RNA molecule
Pentose sugar ( Ribose)
Phosphate group
Nitrogenous base
Give 3 key differences between the structure of RNA and DNA
Pentose sugar is ribose
Only single stranded
Has uracil base in place of thymine
3 different forms of RNA involved in gene expression
mRNA
tRNA
rRNA
What is the function of mRNA
Carries complementary copy of genetic code from the nucleus to the ribosomes
What is the function of tRNA
Carries amino acids to ribosomes to form polypeptide chains
What is the function of rRNA
Combined with proteins to make up ribosomes
What is the purpose of transcription
Is the synthesis of a mature mRNA transcript from a section of DNA
What is the purpose of translation
Is the synthesis of a protein at a ribosome under the direction of mRNA and with the help of tRNA
List 5 functions of proteins
Antibodies Hormones Enzymes Structural Receptors
Who two groups make up an amino acid
Amine and acid groups
What do we call the bond between amino acids
Peptide bonds
What is the name of the enzyme that synthesises mRNA
RNA polymerase
Describe the key stages involved in primary mRNA transcription
- RNA polymerase moves from Gene to the promoter
- unwinds and opens DNA
- mRNA sequence is complementary to one of the two strands
- molecule elongates until a terminator sequence is reached
- resulting in mRNA as the primary transcript
Explain the difference between and intron and an exon
Intron- non-coding sequence of DNA
Exon- coding sequence of DNA
What is removed from the primary transcript during RNA splicing
Introns
What do we call a triplet of bases on an mRNA molecule
Codon
Why is alternative splicing important
Means that we are able to produce more than one protein per gene
Where in the cell does transcription occur
Nucleus
Wheee does translation occur
In the cytoplasm at ribosome
