Gcse Biology Inheritance Flashcards
How many chromosomes are present in a human nucleus
46 single chromosomes or 23 pairs
Are the chromosomes paired in gamete cells
No they are single
How many chromosomes are in a gamete cell
23 single chromosomes
What is the name for reproductive cells
Gametes
What process produces gametes
Meiosis
What are the gametes in a plant
Pollen and egg
What are the features of sexual reproduction
Involves the fusion of male and female gametes
Offspring receives genetic information from father and mother, this causes genetic variation in the offspring.
Why does sexual reproduction produce variation in offspring
Each gamete cell is unidentical to each other, so during fertilisation, the mixing of genetic information from both parents takes place
What’s the features of asexual reproduction
Only enquires one parent
So no gametes involved
So no genetic mixing, offspring are genetically identical to parent.
No meiosis but reproduce by mitosis.
Offspring’s are clones
Where is the only place meiosis takes places
In reproductive organs
What’s the reproductive organs for males and females
Testes for males
Ovaries for females
What is the stages of meiosis
First the cel in the reproductive organ doubles in chromosomes
The cell then divides once to form 2 cells
The 2 cells then divide each against to form 4 unidentical gamete cells
What’s an advantage of sexual reproduction
There is variation in the offspring, so if the environment changes, some can survive
What’s an advantage of asexual reproduction
Only requires one parent.
More time efficient and energy efficient
Can produce a lot of clones if conditions are favourable
What’s a disadvantage of asexual reproduction
There’s no variation in offspring so they are all susceptible to a disease
Name one example of an organism that reproduce both sexually and asexually
The malaria parasite reproduces asexually in human host and sexually in the mosquito
Name an organism that can reproduce both sexually and asexually
Some fungi can reproduce asexually by releasing spores, and sexually to produce variation in offspring
Name one organism that can reproduce sexually and asexually
Strawberry plants can reproduce sexually to produce seed, and asexually by sending out runners. When the runners touch the soil, the identical plant grows into a flowering plant.
Chromosomes consist of what
DNA
Why is DNA important
Determines our genetic information
Describe the structure of DNA
Consists of 2 polymer strands
These two strands wrap around each other to form a double helix
Each polymer strand consist of smaller molecules.
What is a gene
Small section of DNA on a chromosome
What is the role of a gene
It encodes for a specific sequence of amino acids to form a protein
What is the genome
The entire genetic material of an organism
What’s an advantage of studying the human genome
Scientists can link faulty genes to inherited disorder
Helps us to understand and treat inherited disorders
Allows us to trace human migration patterns from the past which helps people find their ancestry.
Give the structure of DNA
The polymer strands consist if nucleotides
Nucleotides have a phosphate group and a sugar molecule attached to a base
What are the 4 bases and what do they link to in DNA
A to t
G to c
The two polymer dna strands are…
Complimentary
How does a protein get its function
The specific order of amino acids causes the protein to have a specific shape, the specific shape determines its function
What determines the order of amino acids in a protein
The sequence of bases in the gene for that protein
