Biology 1: You and Your Genes Flashcards
DNA
Large (polymer) molecule found in the nucleus of all body cells – it’s sequence determines genetic characteristics, such as eyecolour, and gives each one of us are unique genetic code
Chromosomes
Threadlike structures in the cell nucleus that carry genetic information – each chromosome consists of DNA wound around a core of protein
What are DNA strands made of
Bases as well as phosphate groups and sugar molecules
Where are chromosomes found
In the nucleus
How many genes do we have in our chromosomes
Between 20,000 and 25,000 genes in our chromosomes
Why does the order of the bases in DNA strand matter
It determines the order of amino acid’s in a protein
Which Groups do proteins falling into
- functional proteins
* structural proteins
Structural protein
A protein, such as collagen, whose function is to build tissues
Functional protein
A protein such as an enzyme that speeds up a chemical reaction
What does the human Genome project do
Has identified the location of all the jeans on human chromosomes. We call the complete gene set of an organism it’s genome
What does the Human Genome project help us to understand
How do you control or characteristics and development, and can lead to certain diseases
What is the Human Genome project ethical implications
some drug companies want to patent or own jeans. They could then charge of a scientist money to this get the genes, which would restrict research
What factors are controlled by our genes
- Characteristics, for example dimples
- environment for example the presence of scars and dyes hair
- or a combination of these are bodyweight
Where do our genes come from
We inherit dreams from my parents, so we’re similar but not identical to each parent
Variation
Differences between individuals belonging to the same species
What does differences in genes produce
Variation in offspring
Continuous variation
Variation in organisms of features that take any value, for example height
Characteristics controlled by several genes working together
These characteristics will show continuous variation across the population sample the continuous range of colours and different heights
What are the names of a particular characteristic
Genotype
Phenotype
Genotype
And individuals genetic make up, such as whether they are homozygous or heterozygous for a particular gene
Phenotype
The physical expression of the gene; different genotypes can give the same phenotype
What colour genotype refer to
The whole of an individual’s jeans or (more often) the jeans for a particular characteristic,such as if they have dimples the genotype is usually written two letters for example DD
What does the phenotype depend on
The persons genes, but may also be affected by how these interact with the environment
What about identical twins genotypes
Identical twins have identical Genotypes because they develop after fertilised egg splits into two
How do studies of identical twins help us
To understand the effect of the environment on a persons genotype
How are chromosomes arranged
In pairs
Many chromosomes do humans cells have
23 pairs. A total of 46 chromosomes
Where did these 23 chromosomes come from
Excels are eggs (over) and sperm. These have 23 chromosomes, one from each pair
Human baby
The human baby that develops as a combination of genes from its mother and father
Fertilisation
The moment when the nucleus of a sperm fuses with nucleus of an egg
Describe the gene position for chromosomes
Pairs of chromosomes have jeans for the same characteristic at identical positions of each chromosome of the pair
How does mutation occur
Changes to our DNA sometimes occur, causing a mutation. This can take place when sex cells are being made, or after fertilisation
Chromosome mutation
One type of mutation is called chromosome mutation. This results in an individual having extra chromosomes for example a person with an extra chromosome 21 will have Down’s syndrome
How does the combination of chromosomes vary
- The combination of chromosomes in an egg or sperm will always be different for example in an egg crime is own one could have been inherited from the mother, while crime is own two and three could have been inherited from the father etc. So, the combination of chromosomes (and therefore jeans) will be unique to that person – unless he or she has an identical twin
- environmental effects will also add to the variation
Alleles
Different versions of the gene on a pair of chromosomes
Homozygous
An individual who has identical alleles for an inherited characteristic
Heterozygous
And individual who has two different alleles for an inherited characteristic