Genetics Flashcards
What is DNA made of?
Nucleotides
What do nucleotides contain?
A sugar phosphate backbone (sugar molecule and phosphate) and a nitrogenous base
What are the 4 possible bases and their pairings?
Adenine and Thiamine
Guanine and Cytosine
Two polynucleotide strands join together to make a double helix. What type of bond allows this to occur and where are these bonds?
Hydrogen bonds between the nitrogenous bases
3 bonds between GC
2 Bonds between AT
How is DNA effectively stored in the nucleus?
DNA molecules are very long and are coiled up very tightly so a lot if genetic information can fit into a small space
What structure of DNA makes it efficient at replication?
It has a paired structure which makes it much easier to copy itself - called self-replication.
How does the double helix structure help the function?
It makes it very stable in the cell.
How is DNA stored in Eukaryotic cells?
DNA is wound into a double helix, then is wound around histone proteins and then coiled up even more into single chromosomes
How is DNA stored in Prokaryotic cells?
DNA is wound into a double helix then organised into a circular chromosome which coils up to fit inside the nucleus.
DNA contains genes which are instructions for what?
Proteins
Each amino acid is coded by a sequence of what?
3 nitrogenous bases ( the triplet code)
What is an intron?
what are exons?
Introns - All the parts of DNa that don’t code for amino acids
Exons - all the parts that do
What happens to introns during protein synthesis?
They are removed
How does DNA determine our nature and development?
DNA determines amino acid sequence
Proteins and enzymes formed
Enzymes enable metabolic pathways
Metabolic pathways help determine our nature and development
What is a allele?
An allele is a form of a certain gene
How can a gene mutation result in a nonfunctional protein?
Mutation will change the base sequence of DNA
New allele will be produced.
During protein synthesis the new base sequence will code for different amino acids, a non-functional or different protein will be made.
All enzymes are proteins, the new base sequence will change the tertiary structure of the protein which could result in an active site that is the wrong shape- this makes a nonfunctional enzyme (protein)
define diploid
a cell that contains 2 sets of chromosomes
Define haploid
a cell that contains a single set of chromosomes
Define mitosis
A process where a cell is copied. One diploid cell divides to give to identical daughter diploid cells.
Define Meiosis
Cell division that creates the sex cells. One diploid cells divides to make four haploid cells - each genetically different.
Explain how gametes are formed
Process of meiosis
1)
