B11 DNA and Reproduction Flashcards
What structures contain coiled DNA?
Chromosomes
What kind of molecule is DNA?
A polymer
What do genes do?
Code for (tell cells to produce) a certain sequence of amino acids that form a particular protein
List 3 reasons why understanding the human genome is important:
- Identification of disease related genes
- Developing treatment of genetic illness
- Tracing the historic global migration of certain populations
What are the monomers of DNA?
Nucleotides
What are nucleotides made up of?
A sugar, a phosphate group and one base
How are the sugars and phosphate groups arranged in nucleotides?
In alternating parts
What do the order of bases decide?
The order of amino acids in a protein
How many bases code for an amino acid?
3
Which bases link with which?
A links with T and C links with G
What do ‘non-coding’ parts of DNA do?
Control whether or not a gene is expressed/used to synthesise a protein
Where are proteins assembled?
In the ribosomes
What molecule is created using DNA to aid protein synthesis?
mRNA- messenger RNA
Describe how mRNA is used to synthesise proteins:
- 1 strand of a gene is replicated to form mRNA
- mRNA binds to the ribosome
- tRNA carrier molecules bring amino acids
- Carrier molecules contain an anti-codon at the bottom that is complementary to the mRNA codons (groups of 3 base pairs)
- The carrier molecules bind to the complementary codons, bringing the amino acids into the correct order
What do proteins do once they have been assembled?
They fold into a certain shape.
What type of molecules are proteins?
Polypeptides
Name 3 types of protein:
- Structural proteins (i.e. collagen)
- Hormones
- Enzymes
Mutations occur _________
Continuously/randomly
What do mutations do to genes?
Change the sequence of base pairs
Explain the effect of genetic mutations on a protein:
The protein may be altered, as the sequence of base pairs are changed, which affects the way amino acids are arranged in protein synthesis.
Do most mutations have a notable effect on a protein?
No- often little to no effect
How could a mutation affect a structural protein’s ability to carry out a function?
It may lose its strength due to the shape being changed, meaning the structure and support provided are weaker.
What is the effect of a mutation in non-coding DNA?
It could alter how a gene is expressed.
What are the 3 types of mutation?
- Insertions- new base inserted
- Deletions
- Substitutions
What kind of cells have only 23 chromosomes?
Haploid cells- gametes
What process involves the fusion of gametes?
Fertilisation
Why does sexual reproduction create variation?
Male and female gametes fuse, causing the offspring to have a mixture of chromosomal DNA.
What does asexual reproduction produce?
A clone
Why are the daughter cells produced via meiosis not genetically identical?
When the second division occurs, the two sets of daughter cells get different combinations of chromosomes.
List 2 advantages of sexual reproduction:
- Creates variation, which could lead to a survival advantage in an organism
- Selective breeding- aids food production by breeding animals with desirable characteristics
List 2 advantages of asexual reproduction:
- Faster and less energy-intensive- don’t need to find a mate
- Many identical offspring can be produced in favourable conditions
How does the malaria protist reproduce?
Sexually in the mosquito, and asexually in the human host
Why may fungi produce spores sexually?
To increase the chance of survival in unfavourable conditions
True or false- Some plants can reproduce asexually.
True
Define gene
A small section of DNA on a chromosome
Define genome
The whole set of genetic information in an organism
Define mutation
Random alteration in DNA
