Genetic And Biological Development Flashcards
Describe DNA
DNA stands for deoxyribonucleic acid and is a long molecule that contains our unique genetic code. Our genetic code is like a set of instructions for making all the proteins in our bodies. Your genome is made of DNA.
What is a genetic mutation?
A gene that contains a change, like a spelling mistake, that disrupts the gene message.
What is a phenotype?
An observable trait e.g. curly hair
What is a genotype?
The genes that produce an observable trait.
Describe how characteristics are inherited from our biological mother and father.
Parents pass on traits and characteristics such as eye and hair colour through their genes. One characteristics such as blood group can have several gene variations known as alleles. A gene can be recessive or dominant, which can influence whether or not a child will inherit it from their parent.
Explain dominant and recessive genes.
The two copies of genes contained in each of the chromosomes both send coded messages to influence the way the cell works. The actions of some of these genes appear to be more dominant than others. For example, the coded messages from genes that tell the eye cells to be brown is dominant over blue eye colour.
Explain dominant and recessive blood group inheritance.
The A allele is dominant over the O allele, so a person with one A allele and one O allele has the blood group AO.
What are co-dominant genes?
Each allele in the gene pair carries equal weight and will show up as a combined physical characteristic. For example with blood groups, the A allele is just as strong as the B allele, so someone with both copies will have the blood group AB.
What are chromosomes?
They are within the nucleus of the cell, made up of two strands of DNA known as a double helix.
List the three prenatal periods
- germinal/period of the zygote: from conception to end of week 2, rapid cell division and creation of a blastocyst. Implanted into the uterus and creation of the embryonic disk.
- embryonic period: implantation of the blastocyst up until week 8, three layers of cells created from embryonic disk which later become different body parts, structural development. Organogenesis occurs, formation of body parts and organs.
- foetal period: from week 8 until birth, maturation of organs and organs
What is a teratogen?
An agent that causes a birth defect such as alcohol.
What is cell/neuronal proliferation?
Process for creating cells, at the end of this process more cells are created than required.
Explain synapses and synaptogenesis
Synapses are the points between two neurons. Allows information to travel between different parts of the brain. When we are born we have more connections than we need, the creation of these synapses is called synaptogenesis. Our experiences with the world influence which synapses we keep and which ones we lose.
What is myelination?
The process whereby an axon is covered in a fatty substance, acts as insulation and helps transmit electrical signals in the brain faster.
