Inheritance Flashcards
What is DNA
Deoxyribonucleic acid stores genetic information and controls cell activity.
What shape is DNA
Double helix shape
What are the 4 types of nitrogenous base
Adenine, Cytosine, Guanine and Thymine
What is adenine ALWAYS paired to?
Thymine
What is cytosine ALWAYS paired to?
Guanine
How are nucleotides joined together?
Covalent bonds
What do nucleotides consist of?
They consist of a sugar, a phosphate and a nitrogenous base
RNA is _________
Single-stranded
How does RNA differ from DNA
-RNA is single stranded whilst DNA is double stranded
-RNA has a sugar called ribose while DNA has a sugar called deoxyribose
-RNA has the base Uracil instead of Thymine!
Where is messenger RNA (mRNA) formed?
It is formed in the nucleus of the cell.
What process does mRNA do
Transcription
Role of mRNA
mRNA carries the code for building a specific protein from the nucleus to the ribosomes in the cytoplasm.
Role of transfer RNA (tRNA)
-Picks up specific amino acids from the cytoplasm and brings them into position on the surface of a ribosome
-This is called translation
What is a gene
A gene is a length of DNA which codes for a protein
What is the term for every three bases
A codon
What is an allele?
An allele codes for different forms of a protein
Where is DNA wrapped up in?
Chromosomes
How many pairs of chromosomes do humans have
23 pairs
What is mitosis
Cell division which produces genetically identical daughter cells. These cells are diploid.
What is meiosis
Meiosis is cell division that produces haploid gametes, these are not genetically identical and are used for sexual reproduction.
What is genetic variation
Organisms all have different versions of genes which make them different
What does homozygous mean
When a chromosome has the same allele (AA or aa)
What is heterozygous
When a chromosome has both alleles (Aa)
What does dominant allele mean
It only needs one allele present to be expressed
What does recessive allele mean
It needs two alleles to be present to be expressed
What does genotype mean
Genotype is the combination of alleles (Tt or TT or tt)
What does phenotype mean
Phenotype is the characteristic that is actually displace. e.g t is dwarf and T is tall
Tt results in the phenotype Tall
What is codominance
Some alleles don’t show a perfect dominant: recessive relationship but have three possible phenotypes with only two alleles.
