Biology Flashcards
allele
A different form of a gene that codes for a different version of a characteristic.
gene
Section of DNA that codes for a particular trait or characteristic.
genotype
A description of the pair of alleles present for a characteristic.
phenotype
The physical expression of the alleles.
homozygous
Pair of alleles that produce a characteristic are the same, e.g. HH.
heterozygous
Pair of alleles that produce a characteristic are different, e.g. Hh.
dominant
An allele that will always be expressed even when there is only one of these alleles present, represented by a capital letter.
recessive
An allele that will only be expressed when both alleles are of this type e.g. hh.
Gametes
Sex cells
Selective breading
Selective breeding is where: humans bread organisms with specific genetic characteristics.
Cloning
A clone is a geneticaly identical organisms
Why clone plants?
To…
. Protect rare species from extinction
. Protect crops with desierable characteristics
Why clone animals?
To…
. Create cattle with desierable characteristics
. Could be used in medicine
Cuttings
A small part of the plant is cut away(leaves,stem,roots)
It is placed in soil
The cutting will grow into a plant
Tissue cultures
A small group of cells is collected from the plant
Next you place the cells on a substance called Agar
Agar provides the cells with nutrients to grow. next the cells begine to grow
Once it’s roots and shoots are established it can be planted
Embryo transplants
This process begins with selective breading
The farmer then removes and splits off the embryo
The individual embryos will form their own embryos
The embryos can be implanted into host mothers
Adult cell cloning
Begins with a skin cell
Next the nucleus is removed
Next you take an eggcell and remove its neucleus
Insert the removed neucleus into the empty egg cell
The new egg cell will be given an electric shock in order to fertilise
Asexual reproduction
Where there is only one parent so there is no mixing of genetic matirial and the offspring are clones of eachother and of their parent
DNA
Your DNA carries your genetic information. It is like the code of your body.
. It is made up of two strands.
.The strands are joined together by chemicals called DNA bases.
.The strands are twisted together to form a double-helix shape
Variation
The differences in characteristics between individuals of the same species is called variation.
Environmental variation
Some variation is the result of differences in the surroundings, or what an individual does. This is called environmental variation.
Inherited variation
Some variation is passed on from parents to offspring, via genes, during reproduction. This is inherited variation.
Transgenic/ genetic engineering
In genetic engineering, genes from the chromosomes of humans and other organisms can be ‘cut out’ using enzmes and transferd to cells of other organism.
