B12-DNA Flashcards
Describe how protiens are made(6 steps)
- DNA unzips and uncoils in the nucleus
- An MRNA molecule takes a copy of the gene (A-U C-G)
- The MRNA molecule leaves the nucleus and takes the complementary copy of the gene to the ribosome
- The Ribosome reads the MRNA molecules in codons (groups of three bases
5) A carrier molecule carries a specific amino acid complementary(A-U ,C-G) to the Codon . The amino acids start to bond
6) the amino acids bond to form a chain called a protien until a stop codon is reached
What is genetic screening
Genetic screening involves undergoing tests to discover if a person/feotus/embryo is carrying a faulty allele or has a genetic disorder
How can embryos be genetically screened
Embryos can be genetically screened by harvesting cells from a developing embryo . This can be done by:
Sampling feotal cells from the mothers blood
Amniocentisis
Chronic villius sampling
What are advantages of genetic screening
- The people can decide wether or not to have children or continue with the pregnancy
- The family or person affected can plan ahead and get treatment for the condition
- The people affected will know if they will get ill in the future
Describe the structure of DNA
DNa is a chemical found in the nuclues of cells. It is a polymer made up of two strands joined togeter. It is described as having a double stranded, double helix molecules
What is a gene
A gene is a small section of a chromosone that codes for a specific sequence of amino acids to make a particular protien
What is the genome of an organism
The genome of an organism is the entire genetic material of that organism
Why do scientists study the genome
Scientists study the genome to seach for genes linked to different types of disease
Scientists study the genome to help them understand and help treat genetic disorders
Scientists study the genome to help them trace human migration patterns from the past
What are nucleotides
Nucleotides are the building blocks of DNA. They join together to create a double stranded, double helix molecule.They are comprised of a phosphate group,a pentose sugar and a nitrogeous base
During complementary base pairings which bases bond together ?
During complementary base pairings A bases bond with T bases and C bases bond with G bases
What is a chromosone
A chromosone is a long coiled structure composed of DNA and protien
What is an allele
An allele is an alternate/ different form of a gene e.g for eye colour their might be a brown and blue allele
What is a dominant allele
A dominant allele is an allele that is expressed ( even if there is only one dominant allele)
What is a recessive allele
A recessive allele is an allele that is masked by a dominant allele ( recessive alleles only are expressed if they occur in pairs)
What is a homozygous genotype
A homozygous genotype is a genotype where a person has two identical alleles for a specific gene
