Genetics Flashcards
What are DNA strands called?
Polymers
Name the 4 bases for a DNA unit?
Adenine
Thymine
Cytosine
Guanine
What shape describes DNA?
Double helix
Complementary bases
What is matched with A Adenine?
T
Thymine
Complementary bases
What goes with C Cytosine?
G
Guanine
What are complementary bases joined together with?
Weak hydrogen bonds
How is your DNA passed onto the next generation?
Reproduction
What are chromosomes?
Long, coiled up molecules of DNA
Where are chromosomes found?
Nucleus of eukaryotic cells
What determines what protein is produced?
The sequence of bases in the gene
What practical test can you use to extract DNA from fruit cells?
Add detergent and salt
Detergent breaks down cell membranes to release DNA
Salt makes DNA stick together
Who won Nobel prize for their work on DNA?
Crick Watson Wilkins
Why is it useful to use salt when extracting DNA from fruit cells?
Salt makes DNA stick together
How many chromosomes do human cells contain?
46
How many chromosomes in a haploid cell?
23
In flowering plants where are male gametes found?
Pollen
Where are female gametes found in flowering cells?
Ovaries at bottom of stigma
What are normal cells with full number of chromosomes called?
Diploid
What are reproductive cells called?
Gametes
What are animal gametes better known as ?
Sperm and egg cells
What is a zygote?
A fertilised egg
What happens when a male gametes fuses with a female gamete?
Produces a fertilised egg
What happens when a zygote undergoes cell division by mitosis?
Develops into an embryo
What is the difference between meiosis and mitosis?
Doesn’t produce identical cells
Does meiosis happen in other organs?
No just reproductive organs
How many divisions in meiosis?
2
How is genetic variation created?
Mixture of mother’s and father’s genes
What is a gene?
A stretch of DNA that determines a certain trait
What is an allele?
A form of a gene
Eg. Gene for eye colour has several variations
One for blue eyes, one for brown eyes etc.
How many versions or alleles of genes do you have?
2
One on each chromosome
What is homozygous?
If 2 alleles are the same
What is heterozygous?
If 2 alleles are different
Dominant alleles have a capital or small letter?
Capital
Do dominant alleles overrule recessive alleles?
Yes
How can organisms display recessive characteristics?
Both alleles must be recessive
What is genotype?
Part of genetic make up of a cell which determines a characteristic or phenotype
What is a phenotype?
A characteristic
Eg eye colour
Which sex have an X and a Y chromosome?
Males
What letter combination do female chromosomes have?
XX
What maths term is used to determine sex of babies?
Probability
What is genetic variation within a species ?
All dogs are same species
Pug looks different to Dalmatian
What is a genetic mutation?
Changes to base sequence of DNA
What is human genome project?
Research to map over 20,000 genes
How could information from human genome project be used to help prevent individuals from developing certain diseases?
Design new drugs
If doctors know what genes predispose people to diseases individually treated
Identify faulty alleles
Who came up with theory of natural selection and evolution ?
Charles Darwin
What system classifies organisms?
Five kingdom classification system
What are 5 kingdoms?
Animals Plants Fungi Prokaryotes Protists
Name sub divisions of kingdoms?
Phylum Class Order Family Genus Species
What is selective breeding?
Take best plants or animals to breed to get best offspring
Name some attractive features for selective breeding?
Animals that produce more milk or meat
Crops with disease resistance
Dogs with a gentle temperament
Plants that produce bigger fruit
Give 3 problems selective breeding can cause
In breeding and reduces gene pool
Causes health problems or harmful genetic defects
If new disease appears, not much variation so less chance of resistance alleles
