B13 Flashcards
2 stages of protein synthesis?
Transcription and Translation
3 levels of orginisation in a genome?
- Genes
- DNA
- Chromosones
Advantages of Asexual reproduction?
- Only one parent required
- Requires less energy and time
- Lots of offspring can be produced in a short period
Advantages of Sexual Reproduction?
- Creates genetic variation in offspring
- increasing the probability of species adapting to and surviving enviromental changes
Describe the circumstances in which malarial parasites reproduce sexually and asexually
Malaria parasites reproduce sexually in mosquitoes and asexually in their human hosts
Explain mitosis
1) Cell begins to divide
2) Dna replicates to form two copies of each chromosome
3) Nuclear membrane breaks down. chromosome lines up across centre of the cell
4) one set of chromosome pulled to each end of the cell and nucleus divides
5) cytoplasm and cell membrane divide to two identical cell
Diagram of protein synthesis
draw
Diagram of transcription
draw
Disadvantages of sexual reproduction
- Two parents are required
- More time and energy is required so fewer offspring are produced
effects of a mutation
- enzyme also unchanged so substrate doesn’t fit
- active site shape changed so enzyme doesn’t fir
- active site changed shape so a different substrate fits
Explain how a gene codes for a protein
- A sequence of 3 bases in a gene form a triplet
- Each triplet forms an amino acid
- The order of amino acids determines the structure and function of the protein formed
Features of asexual reproduction
- Involves only one parent
- No joining of special sex cells (gametes)
- No mixing of genetic information
- Gives rise to genetically identical offspring known as clones
Explain how meiosis results in genetic variation within the human species.
Specifically, meiosis creates new combinations of genetic material in each of the four daughter cells. These new combinations result from the exchange of DNA between paired chromosomes.
Give 2 examples of inherited disorders
- Cystic fibrosis
- Polydactyly
How are recessive alleles represented?
Using lower case letters
How can human beings have more than 21,000 different chemicals within them?
The human genome has the ability to make many different proteins from the same gene by using it in different ways or by switching parts of a gene on/off.
How do cells divide in asexual reproduction?
By mitosis
How many chromosomes do gametes have?
23 chromosomes
How many chromosomes do humans have?
46 chromosomes (23 pairs)
How many gametes are made in meiosis?
4
Outline the function of genes
To code for particular sequences of amino acids that produce proteins
Outline the process of translation in protein synthesis
1) mRNA attaches to a ribosome
2) ribosome reads mRNA in triplets. Each triplet codes for one amino acid which is brought to the ribosome by a tRNA molecule
3) A polypeptide chain is formed from the sequence of amino acids which join together
Stages of meiosis
1) chromosome makes identical copies of themselves
2) similar chromosome pair up
3) section of DNA get swapped
4) pairs of chromosome divide
5) chromosome divide
State the full name of the 4 bases found in nucleotides
- thymine T
- adenine A
- guanine G
- cytosine C
Suggest one possible effect of a mutation that changes the shape of a structural protein
The mutation could cause the structural protein to lose its strength
Treatment for cystic fibrosis
Physiotherapy and antibiotics
What are “designer babies”?
A designer baby is a baby whose genetic makeup has been selected or altered, often to include a particular gene or to remove genes associated with disease.
What are alleles?
Different versions of the same gene
What are DNA nucleotides made up of?-
- Commom sugar
- Phosphate group
- Bases
What are the 2 types of reproduction?
Asexual and sexual
What are the carrier molecules called in protein synthesis?
transfer RNA (tRNA)
What are the complementary base pairs found in nucleotides?
t-a
g-c