genetics Flashcards
Define sexual and asexual reproduction.
Sexual- process involving fusion of 2 gametes to form a zygote & production of genetically unique offspring.
Asexual- process resulting in genetically identical offspring being produced from one parent .
What does meiosis produce?
4 genetically unique haploid daughter cells.
What is the genome and gene?
The entire genetic material in an organism.
A section of dna that codes for a particular sequence of amino acids.
What is dna and its structure?
Polymer
Double helix
What are nucleotides?
Dna is a polymer (molecule made from many repeating subunits called nucleotides).
Each nucleotide consists of a common sugar & phosphate group with one of four bases attached to the sugar.
What 2 things form the backbone of a strand of dna?
Phosphate and deoxyribose sugar.
What are the four different bases and how do they pair?
Adenine
Cytosine
Thymine
Guanine
A-T and C-G pair by forming weak hydrogen bonds with each other.
How do you extract dna from fruit?
1.Mash fruit and mix into a beaker containing a solution of detergent (breaks down cell membranes) & salt (causes dna to stick together)
2. Filter mixture into test tube (removes debris)
3. Gently and slowlyadd ice cold ethanol to filtrate (causes dna to precipitate)
What’s the difference between a gene and an allele?
A gene is a short length of dna on a chromosome that codes for a particular characteristic whereas an allele is a variation of the same gene.
What’s the difference between genotype vs phenotype?
Genotype is the genetic makeup whereas phenotype is the observable characteristics of an organism.
What’s the difference between dominant vs recessive?
A dominant allele only needs to be inherited from 1 parent for the characteristic to show up in phenotype whereas a recessive allele needs to be inherited from both parents.
What’s the difference between homozygous vs heterozygous?
Homozygous = if the 2 alleles of a gene are the same whereas heterozygous = if the 2 alleles of a gene are different.
How do u model inheritance in pea plants (height)?
Height of plants controlled by a single gene that has 2 alleles: tall and short
(tall is dominant shown as T)
(short is recessive shown as t)
What are the 2 types of variation?
Continuous: small degrees of difference (height, mass)
Discontinuous: distinct differences (blood type, sex, ability to roll tongue)
What are some examples of genetic variation?
Blood group, eye colour, gender, ability to roll tongue etc.
What are some examples of environmental variation?
Accident leading to scarring, eating too much - weight gain, accent etc.
Discontinuous variation is caused by…
Continuous variation is caused by…
Genetic variation
Genetic and environmental variation
What are mutations? What can they sometimes change?
Rare, random changes in the sequence of dna bases in a gene.
The protein the gene codes for.
What are the 3 types of mutations? What happens in each?
Insertions - base randomly inserted, changed amino acid coded for, knock on effect.
Deletions - based randomly deleted, knock on effect.
Substitutions - base randomly swapped, no knock on effect.
Mutations can lead to … which is caused by… and it…
sickle cell anaemia
the change in base sequence of the gene that codes for haemoglobin
hinders oxygen delivery to tissues
What is the human genome project?
A collaborative research effort to determine the dna sequence of the entire human genome.
What were the advantages of the human genome project?
- prediction and prevention of diseases (specific advice on best lifestyle to avoid or delay)
- testing and treatment of diseases (identify faulty alleles more quickly)
- development of new and improved medicines (more specific and effective drugs)
What were the disadvantages of the human genome project?
- increased anxiety and stress (if told you have a high chance of developing a disease)
- pressured into not having children (don’t want to pass genetic disorder down)
- unfair discrimination (people may not want to hire them incase they become ill)
