Topic 3- Genetics Flashcards
(34 cards)
What are gametes?
Reproductive cells
How many chromosomes does a human cell contain?
46
What type of cell are gametes?
Haploid, because they only contain half the amount of chromosomes
What id the fertilised egg also known as?
Zygote
Why is meiosis is a different type of cell division?
Because it does not produce identical cells
How does meiosis introduce genetic variation?
When the cell divides some of the mother’s and some of farther’s chromosomes end up in the cell> The mixture of the chromosomes creates variation
Describe the process of meiosis
on card 16
Describe the process of meiosis
on card 16
In meiosis what is the final product?
4 haploid daughter cells - gametes
Advantages and disadvantages of asexual reproduction?(involves mitosis)
+ Only one parent is needed
+ Can allow organisms to colonise a new area very quickly
- There is no genetic variation
- So if there is a change in the environment then the whole population may be affected
Advantages and disadvantages of sexual reproduction:(involves meiosis)
+ Genetic variation within the population
+ so if the conditions change some will probably survive which can lead to natural selection
- more time and energy
-two parents are needed
Describe the structure of the DNA?
- it has complementary bases A-T , C-G
- they are held by weak hydrogen bonds
Difference between chromosomes and genes?
Chromosomes are long, collided strings of DNA. A gene is a section of the DNA that codes for a particular protien.
How can you extract DNA from fruit cell?
- Mash up some strawberries and put then into container containing salt and detergent
SALT- makes the DNA stick together
DETERGENT- will break down the cell membrane to release the DNA
2> Then filter it out - Then gently add ice-cold alcohol
4.Then the DNA will start to appear as a stringy white participate.
What does the DNA control?
The production of protiens
What are proteins made up of ?
Chains of molecules called amino acids
Explain how a gene can code for a particular protein?
The order of bases in a gene determines the order of amino acids in a protein. Each gene contains a different order of bases, which a gene can code for a particular protien.
Explain how a genetic variant can result in a protein with a very low level of activity ?
The genetic variant could of changed the sequence of amino acids which could affect the shape of a protein.
Describe how a gene is transcribed to form mRNA?
RNA polymers will separate the part of the dna. Once it has been exposed MRNA is produces and then it leaves the nucleus
Suggest why the importance of Mendel’s work wasn’t recognised straight away?
Because people did not have background knowledge of the genes and chromosomes back then.
By what are characteristics in plant was determined by?
Hereditary units
Who did the genetic pea experiment?:
Mendel
What is homozygous ?
2 alleles that are the same
What is heterozygous?
two alleles that are different
