3) Genetics Flashcards
What does mitosis result in?
Formation of 2 genetical identical daughter cells
What is mitosis used in?
Asexual reproduction
What does meiosis result in?
Formation of 4 genetically non-identical daughter cells
What is meiosis used in?
Sexual reproduction
What occurs in the process of meiosis?
1) Each pair of chromosomes replicate and the cells split in two
2) There are now 2 idential daughter cells, the diploid cell divides again
3) This creates 4 genetically different gametes that each have half the number of chromsomes of the parent cell
What are cells that only have one copy of each chromsomes called?
Haploid cells
What does divison of cells in reproductive organs produce?
Gametes with half the number of chromosomes found in all other body cells
What are the features of asexual reproduction?
One parent
No gamete fusion
Offspring are clones
Cells divide by mitsosis
What are the advantages of asexual reproduction?
Faster
No mate
Lots of identical offspring
What are the features of sexual reproduction?
Two parents
Gamete fusion
Offspring are non-identical
Cells divide by meiosis
Advanatges of sexual reproduction?
Artifical selection
Variation in offspring
What organisms can produce both sexually and asexually?
Malaria parasite
Strawberry plants
Fungi
What is the genome?
The entire genetic material of an organism
Whatr are the levels of organisation in a genome?
DNA
Genes
Chromosomes
What are chromsomes?
Long strands of coiled DNA
Chromsomes contain genes
23 pairs per human body cell
What is a gene?
A small section of DNA
What do genes do?
Code for a sequence of amino acids, combining to make a protein
What do amino acids combine to make?
A protein
What is DNA?
A double helix polymer made up of 2 strands
Twister ladder shape
What is a polymer?
A large molecule made up of many subunits
How is DNA extracted from fruit?
1) Grind a sample in soapy water (detergent), this breaks open cells releasing DNA
2) Filter the same to produce a filtrate
3) Slowly pour ice cod ethanol into the filtrate, DNA moves into ethanol by precipitation and can be removed with a wire loop
How does DNA move into ice cold ethanol?
By precipitation
When was the Human Genome Project completed?
2003
What has the Human Genome project improved our understanding in?
Inherited diseases
Personalised medicine
Gene therapy
Gene Identification
What is DNA made up of?
Polymer made up of two long strands of two units that repeat throughout the structure
What is each DNA polymer unit made up of?
A sugar
A phosphate
A base attached to the sugar
What holds together DNA molecules?
Weak hydrogen bonds between opposite pairs
What are the DNA base pairings?
T and A
G and C
Tigers Are Great Cats
What are the two long strands of units that repeat throughtout the DNA structure called?
Nucleotides
What forms the long DNA strands?
The sugar and phosphate
What is the process our body uses to make proteins?
Protein synthesis
What is each amino acid coded for?
A specific sequence of three bases
A codon
What is a codon?
The specific sequence of three bases that code an amino acid
What does the order of bases on the DNA tell us?
The order for combining amino acids to create particular proteins
How do we change the protein made by a gene?
By altering the sequence of bases in that gene
What does the order of amino acids change?
How a protein folds together which affects its structure and function
What stages occur during protein synthesis?
Transcription
Translation
Describe the process of transcription
1) Double stranded DNA is ‘un-zipped’ and one strand is used to template the DNA code in the form of mRNA
2) The enzymes RNA polymerase joins this mRNA template together
3) The mRNA template leaves the nucelus
What is does mRNA stand for?
Messenger RNA
Where does transcription occur?
The nucleus
What is mRNA?
A type of RNA
What is RNA similar to?
DNA but base A pairs with U instead of T
Describe the process of translation
1) The mRNA template is used to guide protein synthesis on ribosomes in the cytoplasm
2) Specific amino acids are delivered by tRNA to add to the forming protein chain (a polypeptide)
What is the forming protein chain in translation called?
A polypeptide
What does tRNA stand for?
Transfer RNA
Where does translation occur?
Ribosomes in the cytoplasm
What is a mutation?
A permament change in the nucleotide sequence of DNA
What is variation?
The differences in characteristics of individuals
What can cause variation?
Genetics
Environment
What is all genetic variation the result of?
Mutations
What 2 things can mutations offer?
Desireable change
Survival advantage
What are the types of muation?
Non-coding DNA
Coding DNA
What is a non-coding mutation?
A mutation that doesn’t affect proteins
What does a non-coding mutation affect?
The transcription process by switching on or off certain genes
What do non-coding mutations cause?
An increase or decrease in the amount of protein produced
What is a coding mutation?
A mutation that affects proteins
What is cystic fibrosis caused by?
A coding mutation in DNA
What did Mendel do?
Performed breeding experiments on pea plants
What did genes used be called by Mendel?
Units
What are alleles?
DIfferent formes of the same gene
When are dominant alleles expressed?
Always expressed regardless of the other allele
When are recessive alleles expressed?
Only expressed if the other allele is also recessive
What does genotype mean?
The combination of alleles and organism has
What does phenotype mean?
An observed characteristic of an individual
When is someone heterozygous?
When they have a dominant and recessive allele
How do we work out the outcome of a monohybrid cross?
Punett squares
What refers to the inheritance of traits determind by a single gene?
Monohybrid inheritance
What are the male sex chromosomes?
XY
What are the female sex chromosomes?
XX
What can human blood groups be split into?
A
B
AB
O
How dominant are the blood groups?
A + B equal
O recessive
How do we know the blood group of someone?
Red blood cells have ‘markers’ on their cell membrane
What causes the O blood group?
I^O I^O
What is cystic fibrosis?
A disorder of cell membranes
Causes thick, sticky mucus to build-up in lungs and digestive system
What is an example of a dominant inherited disease?
Polydactyly
What is polydactyly?
Having extra fingers or toes
What are sex linked disorders?
A disorder caused by a faulty gene on the X or Y chromosome
When is a new species made?
When 2 populations have divereged to the point they cannot breed
