SCIENCE ASSIGNMENT
PART ONE: TERMINOLOGY
Gene: A unit of heredity which is transferred from a parent to offspring and is held to determine some characteristics of the offspring.
Chromosome: A thread-like structure of nucleic acids and protein found in the nucleus of most living cells, carrying genetic information in the form of genes.
DNA: Deoxyribonucleic acid, a self-replicating material which is present in nearly all living organisms as the main constituent of chromosomes. It is the carrier of genetic information.
Mutation: A permanent, heritable change in the nucleotide sequence in a gene or a chromosome; the process in which such a change occurs in a gene or in a chromosome.
Genotype: The genetic makeup of an organism or group of organisms with reference to a single trait, set of traits, or an entire complex of traits.
Phenotype: The physical appearance or biochemical characteristic of an organism as a result of the interaction of its genotype and the environment.
PART TWO: RESEARCH
Downs Syndrome
a) The most common form of Down Syndrome is called Trisomy 21. It got its name due to having one extra copy of chromosome 21. An error in cell division froms nondisjunction, when a sperm or egg cell has an extra copy of chromosome 21 before or during contraception. Downs syndrome is caused by gene abnormality.
b) Downs Syndrome is an autosomal genetic disorder caused by nondisjunction.
c) Common physical signs of Down Syndrome include the following:
· Decreased or poor muscle tone
· Short neck, with excess skin at the back of the neck
· Flattened facial profile and nose
· Small head, ears, and mouth
· Upward slanting eyes, often with a skin fold that comes out from the upper eyelid and covers the inner corner of the eye
· White spots on the colored part of the eye (called Brushfield spots)
· Wide, short hands with short fingers
· A single, deep, crease across the palm of the hand
· A deep groove between the first and second toes
d) Downs Syndrome is normally diagnosed in a couple ways.
Screening tests include an ultrasound or a blood test whilst you're in your first or second trimester. These test can identify if the baby is at risk for down syndrome, although the tests may sometimes provide false-positive or false-negative results.
Diagnostic Tests such as chorionic villus sampling or amniocentesis. These can show if the baby has down syndrome. If you get abnormal results from screening tests it is recommended to get a diagnostic test. Also useful if you are worried about down syndrome in your baby.
Down syndrome can also be diagnosed at birth. A doctor may have a good idea if on the baby’s appearance and results of a physical exam. The doctor will also use a blood test to make sure of their opinions, this may take 2 – 3 weeks.
e) Unfortunately, downs syndrome cannot be cured, although early treatment can assist in helping them lead a productive life. Extra special attention at schools is recommended as they may have trouble understanding cert...
