Topic 2 Flashcards
How are polypeptides formed?
The condensation of many amino acid monomers (causing peptide bonds between amino acids)
Name the main chemical components of an amino acid that surround/bonded to the central carbon atom
H2N (an amino group)
COOH (a carboxyl group)
H (a hydrogen atom)
R group (also known as a variable side group)
What does the R group in an amino acid determine?
The R group (which is different in each amino acid) determines how the amino acid interact and bonds with other amino acids in the polypeptide
What is the primary structure of a protein?
The sequence of amino acids
The primary structure is determined by the gene encoding the protein
What is the secondary structure of a protein?
The folding of polypetide chain due to hydrogen bonds
e.g. beta pleated sheets or alpha helixes
Name 2 common secondary structures
Alpha-helix
beta-pleated sheet (such as in silk)
What is the tertiary structure of a protein?
The 3d shape of the protein due to various interactions
Usually either coiled or folded
What creates the 3D tertiary structure of a protein?
Interactions between R groups (e.g. ionic bonds, hydrogen bonds and disulphide bridges)
When the protein loses its 3D shape it may no longer be functional
What is the Quaternary structure of a protein?
Multiple 3D polypeptides coming together
What are alleles
The different variations of a gene
What are heterozygotes?
Organism that have different alleles for a gene
What do Monohybrid crosses allow us to do?
To predict the genotype of offspring
Are gametes haploid or diploid?
Gametes are haploid so only one allele from each parent is found in the gamete
What can genetic screening identify in individuals?
If they are a carrier of a genetic disease
If they are at greater risk of developing a disease
How likely they are to respond to a particular drug
What is genetic counselling used for?
Advising patients about genetic screening
Advice considers; if screening is advisable, what results of screening mean, how to prevent or treat a condition identified through screening
What is pre-implantation genetic diagnosis?
Pre-implantation genetic diagnosis (PGD) is the ability to screen embryos before they are implanted into the womb
What is pre-natal testing?
Tests during pregnancy to identify genetic abnormalities
What are some Ethical issues around genetic screening?
If a pre-natal test determines that a baby will be born with a serious genetic condition, then parents can decide to terminate the pregnancy.
Results of genetic screening may not be 100% accurate, so decisions could be made on the basis of incorrect information
What are some social issues around genetic screening?
Pre-implantation genetic diagnosis could be used to select features that parents want, rather than simply ensuring the baby is healthy
PGD could lead to designer babies
Some pre-natal tests increases the risk of having a miscarriage slightly
