Simple inheritance in animals and plants Flashcards
What is mitosis
The type of cell division that produces identical new cells
In body cells how are chromosomes found
In pairs
Why do body cells need to divide
To produce new cells for growth or repair
What do chromosomes contain and what must be done with them
Genes/alleles
They must be passed on to each new cell
When do most animal cells differentiate
Early in development and cell division mainly for repair and replacement
Describe the cell division process of mitosis
The normal body cell has four chromosomes in two pairs
as salsa vision starts a copy of each chromosome is made
The cell divides into two forms of two daughter cells
Each daughter cell has a nucleus containing four chromosomes identical to the ones in the original parent cell
What is meiosis
The two stage process of cell division which reduces the chromosome number of the daughter cells
Explain how four gametes are formed from one cell
There are two sets of cell division a body cell divides into two and each divides again
What do gametes have
One set of chromosomes other body cells have two sets
What does sexual reproduction result in
Variation as the gametes from each parent fuse so half the genetic information comes from the father and a half from the mother
Where are stem cells found in adult humans
In bone marrow
What is a stem cell
A stem cell is an undifferentiated cell that can form into many varieties of different cell types when required
What can Stem cells be used to cure
Conditions such as paralysis e.g. by differentiating into new nerve cells
Where else can stem cells be found
in the human embryo
What are some ethical issues to do with extracting stem cells from embryos
The embryos are sometimes destroyed
The embryo does not give consent
What are some advantages for using stem cells from embryos as opposed to using stem cells from bone marrow
Stam cells from embryos can differentiate into all the cells the body needs whereas stem cells found in bone marrow can only change in some limited types of cells e.g. blood cells
Which scientist worked out how characteristics are inherited
Gregor Mendel
What are chromosomes
Large molecules of DNA
What is a gene
A small section of DNA
What structure does DNA follow
Double helix
What does a gene code for
Each gene codes for a particular combination of amino acid which make a specific protein
What can a unique DNA pattern be used to identify
Peoples identity by their DNA fingerprint
Which sex chromosomes are found in human males
X and Y
What is meant by the term phenotype
This is a description of the physical characteristics
What is sex determined by
The X and Y chromosomes
What are alleles
Different forms of a gene
What is a recessive allele
And allele where the effect is masked
What is a dominant allele
An allele that masks the effects of another
Name one Genetic disorder which is controlled by a dominant allele
Polydactyly
What are the chances of a child having cystic fibrosis if one parent has the disorder and the other parent is heterozygous
50% as one parent has to pass on the allele the other parent has a 50% risk of passing it on
What is cystic fibrosis is caused by
A recessive allele
What are genetic diagrams used for
To predict the chances of inheriting the disorder
What is embryo screening
Tests are carried out on the embryo to diagnose possible disorders
What type of stem cells be used in medical research and treatments
Embryonic stem cells
What do we mean by heterozygous individual
The individual has one dominant and one recessive allele is for a condition
Where can embryonic stem cells be taken from
Spare embryos from IVF or created from adult cells or may be taken from the umbilical cord of newborn babies
How many chromosomes does a human have in each body cell
23 pairs, 46
What molecules are Genes made out of
DNA
What is meant by the term genotype
The types of genes present in the cells
Which type of cell division produced two identical cells from the original cell
Mitosis
