Inheritance and DNA Flashcards
How many chromosomes do human body cells contain?
23 pairs
Or 46
Mitosis
Splitting of human body cells into 2 identical daughter cells
How many chromosomes do gametes contain?
The chromosomes are not paired
So there’s only 23
How are gametes made?
Meiosis
Where else does meiosis occur?
In flowers to make pollen
Key feature of sexual reproduction
Fusing of male and female gametes (fertilisation)
Mixing of DNA
In sexual reproduction what is the offspring like?
It receives genetic information from both male and female parents
And because every gamete is different they are varied
Asexual reproduction
Only 1 parent
Not involving gametes being fertilised
In asexual reproduction what is the offspring like?
Because there is no genetic information mixing
All offsprings are genetically identical (clone)
What form of cell division does a sexual reproduction involve?
MITOSIS
NOT MEIOSIS because it doesn’t involve gametes
Examples of asexual reproduction
Plant reproduction by tiny buds which drop off and grow new plants
Advantages of sexual reproduction
Because offsprings are varied, if the environment changes some of the offspring may survive if they’re adapted.
Advantages of asexual reproduction
Only 1 parent required = more efficient in time and energy
Very fast so it can produce many genetically identical offspring rapidly in the right condition
Disadvantages of asexual reproduction
Disease may affect all in a population because they are genetically identical
No variation in offspring
May only be suited to one habitat
DNA
Contains genetic information of a cell
A large polymer made up of 2 twisted strands
What is the name of the structure in DNA?
Double helix
Chromosomes
In a cell’s nucleus
Long threads of DNA
Gene
Small section of DNA in a chromosome that codes for a particular characteristic
How do genes code for particular characteristic?
Codes for a specific amino acid that makes a specific protein
This protein determines the characteristic that can be inherited
Size of DNA structures in a cell?
(Biggest to smallest)
Nucleus > chromosome > DNA > gene
Genome
The entire genetic material of an organism
Why is studying the genome important?
Search for hereditary diseases
Look for hereditary disease treatment
Find where early humans migrated to
