Chapter 8 (EXAM 2) Flashcards
What are genes
Sequences of nucleotides, a protein, that codes for a protein
What are proteins
Made of amino acids, connected by peptide bonds, structural and enzymatic
Describe DNA
double helix
Alternating phosphate groups followed by sugar
Adenine-Thymine
Guanine-Cytosine
What is a nucleotide
Sugar, phosphate and base together
What is a nucleoside
Just a base and a sugar, no phosphate
DNA vs RNA
Made of deoxyribose sugar
two strands, double helix
uses the base C, G, A, T, during replication A binds to T
Made of ribose sugar
3 types: messenger RNA, ribosomal RNA, transfer RNA single strand
has bases C, G, A, U, during production A binds to U
What is a mutation
A change in DNA, natural occurrence but environment can force a change
Most result in no change in the protien and no change in organism
Can occasionally be harmful to the environment, or beneficial
benefits includeL resistance to microbial agents, pathogenicity: generating disease
What is a mutagen
Something that causes mutations, example is UV, can lead to cancer
Causes 2 T to bind together and is cut out.
Too much UV can lead to major changes in DNA that the body can’t recover from leading two growths and cancers
What is a frameshift mutation
Is caused by aflatoxin
Is a change in DNA, gene code changes and it interferes with the proper protein being reproduced
If caused by random or a mutagen, one base will be kicked out and everything will be shifted over. Now making a whole different amino acid and a different amino acid means a different charge which means the protein will be shaped differently and is now nonfunctional to the enzyme
What is a base substitution
Instead of C followed by a C, it’s followed by T because the code was substituted.
Can occur by random mutation or mutagen.
The problem with this is that the amino acids have charges on them and the charge will cause it to change it’s shape so the protein won’t fit the enzyme
What is insertion
Opposite of frameshift
A base will be thrown in instead of being kicked out
What is translocation
Occurs in eukaryotes only
Non homologous chromosomes exchange genes
Replication
Helicase tears apart weak hydrogen bonds, helps with the unwinding for replication
Separates A from T and C from G
The new bases will be brought to the exposed unpaired by DNA polymerase enzyme to create new strands of DNA
What is the leading strand
Light colored strand that is made continuously
Made of the original DNA strand, 5-3 direction
What is the lagging strand
Made discontinuously and those spaces have to be filled in by chances of Okazaki fragments.
Takes longer than the leading strand and jot as fast
What does DNA gyrase do
Relaxes supercoiling of the replication fork
Transcription
Making a close copy of DNA
Template is used as the pattern to build mRNA, its one half of the DNA strand
RNA polymerase brings in the base pair and mRNA is built
The codes will make the recipe for the amino acids just like in DNA
What are the stop codeons
UAA UGA UAG
What is an exon
Segments that contain genes that will be expressed, transcribed and translated
Protein will be made from them
What are Introns
Contain info that does not code for production, isn’t a recipe