DNA & Inheritance Flashcards
Describe the structure of DNA
-It is a Polymer made of many nucleotide monomers.
-It is made of 2 strands in the shape of a double helix.
Give the letters that represent the 4 bases in DNA
A T C and G
Describe the pairing rules in DNA
A pairs with T
C pairs with G
Name the 4 bases in DNA
Adenine(A)
Thymine (T)
Cytosine(C)
Guanine(G)
Describe transcription
1) DNA unzipped
2) Complementary mRNA nucleotides bind and are joined together
3) mRNA detaches and leaves the nucleus
Describe translation
1) mRNA travels to a ribosome
2)Carrier molecules carry specific amino acids to the ribosome based on the mRNA sequence.
3)The amino acids are joined together.
How does the sequence of DNA affect the protein made in protein synthesis?
DNA is a triplet code where 3 bases code for one amino acid and the order of amino acids determine the protein produced.
What is genetic profiling?
A method of comparing DNA by cutting it into fragments and comparing the fragments with each other
Give 3 uses of genetic profiling
- Paternity testing (working out who is the biological parent of a child).
-Forensic identification (matching a chemical to DNA left at a crime scene).
-Matching an organisms DNA to classify it
Give 2 benefits of genetic profiling
•It can help you catch criminals
•It can be used to identify the presence of disease-causing genes.
What are the ethical issues surrounding genetic profiling?
It could be used against people by insurance companies based on a persons predisposition to certain diseases.
What is a gene?
A section of DNA That codes for a protein
What are alleles?
Different versions of the same gene.
What is a chromosome?
Tightly packaged DNA around histone proteins
What are gametes?
Gametes are sex cells (sperm or eggs).
What is a dominant allele?
A version of a gene where only one copy is needed for it to be expressed
What is a recessive allele?
A version of a gene where two copies are needed for it to be expressed
What is meant when an organism is homozygous?
When an organism has two copies of the same allele (two recessive or two dominant).
What is meant when an organism is heterozygous?
When an organism has two different versions of the same gene ( one dominant and one reccessive).
What is the genotype?
The genes present for a trait.
What is the phenotype?
The visible characteristic
What is selfing?
When gametes from the same parent fuse (e.g. when pollen from a plant lands on the stigma of that same plant).
How are the dominant alleles represented in a punnet square?
They are represented using uppercase letters
How are recessive alleles represented in a punnet square?
They use the lowercase version of the same letter as the dominant alleles.
What is genetic engineering?
Altering the genome of an organism
What is a transgenic organism?
An organism that contains foreign DNA
Give 2 advantages of genetically modified crops
-Better crop yields
-Food will last longer and taste better
Give 2 disadvantages of genetically modified crops
-The new genes can easily spread to other plants in the environment.
-We don’t know what long term effects GM crops cause on health.
