Genes And Dna Flashcards
Pros of GM plants
Long lasting fruits
Contain more: vitamins, nutrients
Can produce: human antibodies, antigens
Resistance to: weed killers, frost, pests, diseases
Genetically modified plants
Introduce a new gene into a plant cell
Produce a whole plant from that single cell
Agrobacterium inserts plasmids into plant cells
Cons of GM plants
Pests may become resistant to the plants
Expensive
Worries about them interbreeding with wild plants
GM bacteria, single celled
Easy to see the effect of the inserted gene
GM bacteria
Used to make human insulin
Enzymes for washing powders to work at high temperatures
Making human growth hormone
The nucleus caontains
Contains chromosomes
Chromosomes have
Have genes located on them
Genes are
Sections of a DNA molecule
Controls certain characteristic developments
Codes for specific proteins
Exists in alternative forms called alleles
Alleles
Give rise to differences int he inherited characteristics
Human cells diploid number
46 cells
Human cells haploid number
23 cells
Sex of a person
Controlled by one pair of chromosomes
Sex- female chromosomes
XX
Sex- male chromosomes
XY
Mutations
Rare, random changes in the genetic material that can be inherited
DNA
Double helix structure
Can reproduce itself
DNA paired bases
Admine, thymine, guanine, cytosine
A-T
G-C
Recombinant DNA
DNA from two different species
Transgenic / genetically modified organism
An organism that receives a new gene from a different species
Restriction enzymes
The enzyme used to cut the gene
Ligase enzymes
The enzyme used to stick the gene
Genetic modification is
Cutting a gene of an organism
Inserting it into the DNA of another
How is Genetic modification done
By using special enzymes
To cut the gene out of a chromosome and sticking it into another
Viruses in Genetic modification
Used to transfer pieces of DNA from one organism to another
Homozygous
Both Alleles are the same
Heterozygous
Two different alleles
Phenotype
The physical characteristic of an organism due to a pair of alleles
Genotype
The alleles of a cell/ organism has for a particular feature
Codominace
Neither allele is dominant, both contribute to the appearance of the offspring
Asexual reproduction
No sex cells
No meiosis
Cloning through asexual
A part of the organism grows and forms a genetically identical organism by meiosis
Clones
Identical offspring
Sexual reproduction
Two sex cells combine to form a new diploid cell (zygote) at fertilisation
Identical twins
Formed from the same zygote
Meiosis
Results in sex cells (gametes)
Two cell divisions
Chromosomes divide randomly between the daughter cells so they aren’t identical
Mitosis steps
Four chromosomes
Each chromosome copies itself
The cell divides into two
Each new cell has a copy of each of the chromosomes
Mitosis
Results in two identical daughter cells
The cells are diploid
Zygote
Formed after fertilisation, made by meiosis
Mitosis in our body
Growth, repair, cloning, asexual reproduction
All the cells in our body formed this way (mitosis of the zygote)
Important for the replacement of cells (skin, gut, blood cells)
Meiosis steps
One cell: each chromosome copies itself
Divides once
One chromosome from each cell will combine with one other from another cell
Four cells produced (each with half the chromosome numbers of the original cell)
A mutation
A change in the DNA of a cell
When do mutations occur
When the DNA is replicating
As a cell divides
Outcomes of mutations
A gene might now code for a different sequence of amino acids
They effect the way an organ works (grow)
Can be passed on to next generation if takes place in the sex cells
Whole chromosome mutations
Result in the death of the cell
Body cell numbers
Diploid
46 chromosomes
23 pairs of homologous chromosomes
These decide the sex
Sex cells (gametes)
Have only one of each pair
Only 23 chromosomes each
They are haploid
Chromosomes
Contained in the nucleus of the cell made up of DNA
DNA
Molecules made up of inherited information
Genes
Parts of DNA that control different inherited characteristics
Control the production of specific proteins in a cell
Come in two forms called alleles
Alleles
Each one codes for a different form of the same thing
Dominant and recessive
Dominant allele
The character they code for shows in the appearance of the individual
Recessive allele
The character they code for only shoes if both alleles are recessive
