IMMS: Genetics Flashcards
DNA; Autosomal inheritance; X-linked inheritance; Multifactorial & non-Mendelian inheritance; DNA mutations; Genetic testing & society
What is a macromolecule?
A large complex molecule, often polymers of smaller molecules (monomers). Examples of macromolecules include DNA, proteins, carbohydrates, and lipids.
What is a heterogenous structure?
Made up of different components e.g. DNA, haemoglobin.
Why is water polar but uncharged?
Water molecules are polar because they have an uneven distribution of charge: oxygen end = negative, hydrogen end = positive. Overall they have no net charge.
What is the chemical structure of a carbohydrate?
Chain of carbon with attached water molecule.
Cn(H2O)n
What is a disaccharide?
Two monosaccharides (carbohydrates) linked together.
What is the difference between an oligosaccharide and a polysaccharide?
Oligosaccharide = 3-10 monosaccharides.
Polysaccharide = more than 10 monosaccharides.
What is an isomer?
Molecules made up of the same atoms but have a different structure.
What is a hexose?
A monosaccharide with 6 carbon atoms. E.g. Glucose.
Name two ways to classify a monosaccharide.
- Number of carbon atoms. E.g. Triose = 3 carbon atoms.
- Type of carbonyl group (if carbonyl group is a ketone, monosaccharide is a ketose, if an aldehyde, it’s an aldose).
What is a carbonyl group?
A carbon atom double bonded to an oxygen atom.
What differs in molecular structure between a ketone and an aldehyde?
The position of the carbonyl group (aldehyde has carbonyl group at the end of the carbon backbone, ketone has carbonyl group in the middle of the carbon backbone).
What sort of bond between a carbohydrate and another functional group forms a glycoside?
A glycosidic bond.
What sort of bond joins monosaccharides to make di/oligo/polysaccharides?
O-gylcosidic bond (bond via oxygen atom)
What bond joins the nitrogenous base and pentose sugar in nucleotides?
N-glycosidic bond (bond via nitrogen atom)
What are the three components of a nucleotide?
Nitrogenous base (e.g. adenine), pentose sugar (deoxyribose in DNA, ribose in RNA), phosphate group.
Name the purines.
Adenine and guanine.
Name the pyrimidines.
Cytosine and thymine (uracil in RNA).
Which nitrogenous bases are joined by 2 hydrogen bonds?
Adenine and thymine (uracil in RNA).
Which nitrogenous bases are joined by 3 hydrogen bonds?
Cytosine and guanine.
How are nucleotides joined together to form DNA?
Polymerised by covalent bonds into long chains.
What does antiparallel mean in relation to DNA?
DNA alpha helix is made up of two antiparallel strands. One running 5’ to 3’ and the other in the opposite direction 3’ to 5’ (which way up the pentose sugar is) this causes the twisting of the two strands.
How is DNA supercoiled to fit into the nucleus?
Antiparallel double helix wrapped around histone proteins to form a nucleosome. Nucleosomes fold together to make a chromatin fibre. Chromatin is tightly coiled together to form a chromosome.
How long does DNA replication take?
8-12 hours.
What is the function of DNA helicase?
Enzyme which separates double-stranded nucleic acids into single strands in DNA replication, repair, and transcription.