B12 Genes Flashcards
What are genes
Genes are sections of chromosomes that carry specific information.
What is an allele
An allele are many different versions of genes
What is a genotype
A genotype is a combination of genes/alleles that an individual has
What is a Phenotype?
The physical presentation of the genes/alleles.
How do you refer to a Dominant allele
Dominant is a capital letter
How do you refer to a recessive allele?
You refer to a recessive allele with a lower case letter.
Genetic screening
Cells can be taken from an embryo / foetus and tested or ‘screened’.
These processes check for alleles that cause genetic disorders.
This can be ‘pre-implantation’ by screening embryos for faulty alleles during IVF, or it can be post-implantation (e.g amniocentesis)
What is an Amniocentesis
Amniocentesis is a prenatal test in which a small amount of amniotic fluid is removed from the sac surrounding the fetus for testing. The sample of amniotic fluid (less than one ounce) is removed through a fine needle inserted into the uterus through the abdomen, under ultrasound guidance. The fluid is then sent to a laboratory for analysis. Different tests can be performed on a sample of amniotic fluid, depending on the genetic risk and indication for the test.
Chloric villis sampling
Chorionic villus sampling (CVS) is a prenatal test that is used to detect birth defects, genetic diseases, and other problems during pregnancy. During the test, a small sample of cells (called chorionic villi) is taken from the placenta where it attaches to the wall of the uterus.
Chorionic villi are tiny parts of the placenta that are formed from the fertilized egg, so they have the same genes as the baby
Advantages of foetus screenings.
Screening procedures are becoming more reliable and accurate all the time.
Allows you to see any faulty information about a foetus and whether the foetus should be terminated because of unhealthy-ness or a disorder.
Disadvantages of embryo screening
The process used to collect cells from a developing foetus increase the risk of miscarriage. Can produce false positive or false negative result. This can lead to the result of the termination of a healthy pregnancy or the unexpected birth of a child with a genetic disorder
What is a Genome?
The entire genetic material of an organism
How many chromosomes do we have?
We have 46 Chromosomes
Name two gametes produced by humans
Sperm and egg
Asexual Reproduction
Asexual reproduction only involves one parent. The cells divide by mitosis. There is no joining of special sex cells and so there is no mixing of genetic information. As a result there is no variation in the offspring.
Asexual reproduction gives rise to genetically identical offspring known as clones. Their genetic material is identical both to the parent and to each other. Only mitosis is involved in asexual reproduction.
Asexual reproduction is very common in the smallest animals and plants, and in fungi and bacteria. However, many larger plants, such as daffodils, strawberries, and brambles, can also reproduce asexually. The cells of your body reproduce asexually all the time. They divide into two identical cells for growth and to replace worn-out tissues.
