Inheritance, Variation and Evoloution (Paper 2) Flashcards
2 main ways that organisms can reproduce
Sexual and asexual reproduction
True or false, some organisms can reproduce through both types of reproduction
True
E.g plants
What is fertilisation
Fusion of male and female gametes
Name for fusion of male and female gametes
Fertilisation
Why are the offspring of sexual reproduction genetically different to the parent
They contain a mixture of both parents genes, not just one
During sexual reproduction in plants which 2 gametes fuse together
Pollen and egg
3 examples of gametes
Sperm, egg, pollen
True or false, gametes only have half the genetic material of a normal cell
True
True or false, sexual reproduction always has to involve sex/ sexual Intercourse
False, as long as it involves the fusion of male and female gametes
E.g when plants reproduce through combination of pollen and egg cells
Which type of reproduction involves gametes
Only sexual
Does asexual reproduction involve any gametes
No
(Only sexual reproduction does)
In asexual reproduction is there any mixing of genetic material
No (as there’s only 1 parent)
In which type of reproduction are all the offspring identical clones
Asexual
Which type of reproduction is achieved by mitosis
Asexual
E.g in eukaryotic organisms, fungi and plants
Which process is used to create gametes
Meiosis
What does DNA stand for
Deoxyribonucleic acid
What is the chemical that all our genetic material is made of
DNA (Deoxyribonucleic acid)
True or false, DNA is a polymer
True
It’s made up of lots of similar units stuck together
What is special about the 23rd pair of chromosomes
They are the sex chromosomes- there is an X chromosome and a Y chromosome
(Women have 2 X, men have 1 X and 1 Y)
Name for small section of DNA that codes for a particular type of protein
Gene
What is a gene
A small section of DNA that codes for a particular type of protein
How many different types of amino acid are there
20
Name for entire set of genetic material in an organism
Genome
What is meant by genome
Entire set of genetic material in an organism
What type of structure does DNA have
Double helix structure
The DNA in typical human cells is found in tight coils known as what
Chromosomes
The chromosomes in the 23rd pair are known as what
Sex chromosomes
DNA can code for proteins by coding for the sequence in which what are joined together
Amino acids
Name for specific diseases that genes can cause
Inherited disease
3 things scientists have found by studying the whole human genome
Genes linked to different diseases
Understand and treat inherited disorders
Trace human migration patterns from past
Name for different versions of a particular gene
Alleles
What is meant by alleles
Different versions of a particular gene
How many versions of each gene do we have and why
2
1 from each parent (each different version is a different allele as the height gene from one parent might be really tall but the height gene from the other might be really small so even though they’re both height genes they’re different versions)
Alleles can be either dominant or what
Recessive
In order to be expressed, how many recessive alleles need to be present
2
Phenotype meaning
Characteristics expressed by an organism as a result of their genotype
Homozygous vs heterozygous
Homozygous= an individual carries 2 copies of the same allele for a trait (e.g 2 brown eye)
Heterozygous= an individual carries 2 different alleles for a trait (e.g 1 brown eye, 1 blue eye)
Genotype
Combination of alleles an individual has
E.g 1 blue eye and 1 brown eye
Term used to describe combination of alleles an individual has
Genotype
2 Advantages of sexual reproduction
Variation in offspring
If the environment changes, the offspring may have a survival advantage by natural selection due to their genetic variation
3 Disadvantages of sexual reproduction
Much slower than asexual reproduction
(Finding a mate and reproducing) is time consuming + requires lots of energy
6 Advantages of asexual reproduction
Only 1 parent needed
Time efficient (don’t need to find mate)
Energy efficient (don’t need to find mate)
Faster than sexual reproduction
Successful traits passed on as offspring are identical
Many identical offspring can be produced when conditions are favourable
2 disadvantages of asexual reproduction
Reduced genetic variation- offspring may have survival disadvantage if environment changes
Harmful mutations in parent are passed down to all offspring
Name for each monomer in DNA polymer
Nucleotide
What 3 parts is a nucleotide made up of
Phosphate
Sugar
Base
A phosphate, sugar and base make up what
A nucleotide (the monomer in DNA)
True or false, every nucleiotide has exactly the same phosphate and sugar
True (it’s just the base that can be different)
Out of the phosphate, sugar and base which is the one that can vary across different nucleotides
Base
(Phosphate and sugar are always the same)
4 different bases
T A C G