B2.7 Cell Division and Inheritance Flashcards
What is fertilisation
When a male gamete fuses with a female gamete
How many sets of chromosomes are in a normal body cell?
2
How many sets of chromosomes are in a gamete?
1
What is DNA?
DNA carries the genetic code for every living thing
It is unique to each being apart from in identical twins
What is a gene?
A gene is a section of DNA that codes for a specific protein by ordering Amino Acids
What is a chromosome?
Chromosomes are made from long chains of DNA
They are found in the cell nucleus
By what process do body cells divide?
MITOSIS
In which division process is genetic material COPIED and the cell forms two IDENTICAL cells?
MITOSIS
What division process is for growth?
Mitosis
Where are male gametes (sperm cell) produced?
Testes
Where are female gametes (egg cell) produced?
Ovaries
What type of cell division produces gametes?
MEIOSIS
After fertilisation, how does the cell grow into a baby?
Mitosis
What is cell differentiation?
When cells specialise to complete different functions
This usually happens early on
What is a stem cell?
A stem cell is a cell coming from embryos or adult bone marrow
How is a stem cell useful?
Stem cells can be made to differentiate to become any kind of human body cell
They could be used to help treat PARKINSONS, and PARALYSIS
What is the process of meiosis?
Meiosis forms gametes
- A parent cell divides
- Similar chromosomes pair up
- Parts of the DNA are swapped
- These cells then divide
- The chromosomes divide
(Look in book better diagram)
As a result of mitosis, how many cells are produced?
2
How many pairs of chromosomes are in a human body cell?
23
How many times does the cell divide in MEIOSIS?
Twice
How many cells does meiosis create?
4
What are alleles?
Different forms of genes
What chromosomes causes the offspring to be male?
XY
Why are some genetic conditions more common in males than in females?
One of the male chromosomes is missing a part so if the other chromosome coding for that function is faulty, there is no backup
In females, both chromosomes must be faulty
When will a dominant allele present?
When there is one or more of it there
When will a recessive allele be visible?
When there is a pair
What did Gregor Mendel discover?
Speciation / Variation / Inheritance
How did Mendel discover variation in genes?
He bred pea plants
- He bread different characteristics (eg tall/short, wrinkly/smooth red/white flower) for generations until the offspring was pure
- He then bread the two opposing characteristics together
- He noticed that some genes (eg red flower) were dominant whereas some (eg white flower) were recessive
What gene type causes polydactyly?
DOMINANT
What is polydactyly?
Extra fingers or toes
What allele causes cystic fibrosis?
RECESSIVE
What is cystic fibrosis?
Cystic fibrosis affects cell membranes causing the production of thick and sticky mucus
What is embryo screening?
Observing an embryo to identify any genetic disorders
What is a genotype?
The genotype is the genetic formation of an allele eg Ff FF ff
What is the phenotype?
The phenotype is the physical characterisation of the genotype eg Brown hair Blue eyes Polydactyly
What does it mean to be HOMOZYGOUS for a gene?
Carry two of the SAME alleles
eg
FF
ff
What does it mean to be HETEROZYGOUS for a gene?
Carry two DIFFERENT alleles
eg
Ff
fF
