Genetics Flashcards
What’s meiosis
The dna replicated then divides itself twice to form 4 haploids , 4 separate daughter cells
What’s mitosis
DNA replicates then divides to form 2 diploids, 2 identical daughter cells
Stages of mitosis
Remember IPMATC
- Interphase
- Prophase
- Metaphase
- Anaphase
- Telophase
- Cytokenisis
How many chromosomes do humans have
46
2 pairs of 23
What’s a diploid?
A cell that has 46 chromosomes
What’s a haploid?
A cell with 23 chromosomes
What’s the result of mitosis ?
2 identical daughter cells these are diploids
Result of meiosis
4 non identical daughter cells , these are diploids (23 chromosomes pairs 92 in total )
What’s Gregor Mendel known for?
He realised traits can skip generations, found dominant and recessive alleles
What is an allele?
Different forms of a gene
What’s a dominant allele?
Only needs to be present on one allele to control the characteristics
What’s a recessive allele?
Needs to be present on both to control the characteristic ( phenome)
What does heterozygous mean?
You carry two different alleles. Eg. Aa
What does homozygous mean?
Carry the same allele eg. aa or AA
What’s a nucleotide
A sugar phosphate base
What are the complementary base pairs
A,t
C,g
A polymer is…
Many repeating units
Bases are connnected with…
Hydrogen bonds
How many hydrogen bonds are there between a,t
2 hydrogen bonds
How meant Hydrogen bonds are between g,c
3 hydrogen bonds
What’s a sequence of 3 bases called
A codon
How many different amino acids are there?
20
What type of molecules are proteins?
Macromolecules (polymer)
What are the monomers of protein
Monomer = one unit
Different amino acids
What happens to the amino acid chain when it’s done
Folds up to a certain shape. Shape determines size of the protein
4 things proteins are used for….
Structural components
Catalysts
Hormones
Antibodies
Stages of protein synthesis…
Transcription
Translation
What is transcription?
Taking a single gene of dna and copying it into the structure of mRNA
What’s translation?
mRNA is used as a template to form an amino acid chain
Where does the mRNA travel to once it’s made
Ribosomes
Where is RNA polymerase attached to?
A gene in the region that doesn’t code for a protein
What does helicase do?
Separates 2 strands of dna by breaking the hydrogen bonds between the pairs
What bases does the mRNA strand have?
Still g,c however in a,t T gets replaced by u
G,C. A,U
Where does the mRNA exit through when transcription is complete
Nuclear pores
What does mRNA attach too?
Ribosomes
What molecule is the amino acid collected by?
tRNA ( transfer RNA)
What happens when ribosomes combine amino acids
A polypeptide chain is formed . Some proteins need multiple polypeptide chains to be formed
What are genetic disorders?
Inherited conditions in humans
What’s polydactyl?
Born with extra fingers or toes, caused by a dominant allele
Is cystic fibrosis caused by a dominant or reccesive allele?
Recessive
What s a gene?
a series of bases on a DNA molecule which codes for a series of amino acids in a
What’s a chromosome?
A thin strand of dna
What’s a phenotype ?
The observable characteristics of an organism
What’s a genotype ?
The alleles behind a certain trait
What’s asexual reproduction?
Where one parent can produce a new life
Where does asexual reproduction often happen?
Fungi
Bacteria
Is meiosis or mitosis used for asexual reproduction
Mitosis used used for asexual reproduction as two identical diploid cells are made.
What does parthenogenesis mean?
The ability to reproduce asexually.
Unfertilised egg develops into new individual
It’s very rare
What’s an example of something that can reproduce asexually?
Aphids, also known as greenfly can reproduce asexually
How to know if something is asexually reproductive ?
There’s no fusion of gametes
Genes from only one parent
Offspring show no variation and are identical
Describe the structure of RNA.
Single stranded
Ribose sugar
5 carbon sugar
Phosphate group
Adenine, uracil,cytosine, guanine
What are the 3 main types or rna? What do they do
Messenger rna (mRNA)- Transfers dna to code for ribosomes
Transfer rna ( (tRNA) bring amino acids to ribosomes for protein synthesis
Ribosomal RNA ( rRNA)- ribosomes are made of rRNA and protein
What do gene mutations result from?
Changes in a singlegene
What do chromosomal mutations result from?
Changes in whole chromosomes
What’s a point mutation?
Affects one nucleotide, thus occurring at a single point on a gene
What’s frameshift mutation?
Inserting an extra nucleotide or deleting a nucleotide causes the entire code to shift
