Inheritance Flashcards
(14 cards)
1
Q
What is a codominant allele
A
- both alleles
- expressed
- in phenotype
2
Q
What is polygenic
A
- traits determined by multiple genes
3
Q
What is DNA structure
A
- double helix
- 2 strands that have been coiled / twisted around each other
4
Q
Describe transcription
A
- DNA helix is unzipped
- RNA polymerase binds to one of the two DNA strands
- (the DNA strand it binds to is called template strand)
- mRNA nucleotides match to their complementary base on the template strand
- (like A T G C -> U A C G)
- mRNA nucleotides are then joined together by RNA polymerase
- this creates a new template strand of the original DNA
- mRNA leaves nucleus
- and travels to ribosome for translation
5
Q
Describe translation
A
- ribosome reads the mRNA in triplets (codons)
- each codon codes for a specific amino acid
- tRNA molecules bring the correct amino acids to the ribosome
- each tRNA has an anticodon
- (so it knows which amino acid belongs where in the protein and with which codon)
- this anticodon matches the mRNA codon
- all amino acids are joined together to form a protein
6
Q
Transcription v translation (4)
A
- Location:
- transcription in nucleus
- translation in cytoplasm
- Produces:
- transcription produces mRNA
- translation produces amino acids / protein
- Starts with:
- translation starts with DNA
- transcription starts with mRNA
- Using tRNA:
- no tRNA used in transcription
- tRNA used in translation
7
Q
Why does increased transcription in cells affect growth
A
- more mRNA made
- more translation
- more proteins produced
- enzymes / tissue
8
Q
What does a change in the DNA of a microorganism mean for the microorganism (5 + 3)
A
- different sequences of bases in DNA
- transcription
- changes mRNA / codons
- translation
- changes tRNA / anticodons / amino acids
- changes structure / shape of protein
- what it can affect:
- growth + digestion
- changes active site
- so enzyme not functional
9
Q
Why may a change in DNA not affect phenotype of organism
A
- some codons code for same amino acid…
- so no change in protein
- active site not changed
- allele for mutation may be recessive
- so not expressed in phenotype (if heterozygous)
- mutation may occur in a non-coding sequence of DNA
10
Q
How is protein made in a cell
A
- transcription
- mRNA leaves nucleus and enters cytoplasm
- ribosomes
- tRNA brings attached amino acids
- codons / anticodons
- translation
11
Q
How do cells use RNA to produce proteins (6)
A
- ribosomes (bind to RNA)
- translation occurs
- codon of RNA codes for an amino acid
- tRNA binds to RNA / anticodon binds to codon
- tRNA brings amino acids
- amino acids are joined together (to form protein/polypeptide)
12
Q
Differences between structure of DNA and RNA
A
- DNA:
- double stranded helix
- contains deoxyribose
- contains thymine (T)
- longer molecule
- RNA:
- single stranded
- ribose
- contains uracil (U)
- shorter molecule
13
Q
What is a mutation
A
- random change to DNA
14
Q
How can a mutation affect phenotype (4)
A
- mutation is a random change to DNA
- change in bases (of DNA)
- change (in sequence of) amino acids (in the proteins)
- (this could) produce a different protein
