Background Review Flashcards
1
Q
Describe DNA
A
- universal genetic material of all life
- double stranded helix, formed by two ANTI-parallel DNA strands, pair complimentary bases via hydrogen bonds
- human genome has genomic loci
- humans diploid with 23 pairs of chromosomes
2
Q
Genomic loci
A
- has cis sequences: the when, where and how much
- has trans sequences: the protein coding
3
Q
The two major functions of DNA
A
- stores heritable genetic info
- portion carries embedded info; once the code is solved/read using genetic code, proteins can be produced (proteins are the workers of the cell)
4
Q
Describe the structure of DNA
A
- every cell carries one genome in the nucleus
- DNA is packed tightly in nucleus into chromosomes
- humans have 23 pairs of chromosomes (varies in animals)
- DNA includes nucleotides
5
Q
Nucleotide
A
- base building block of DNA
- composed of base, sugar, and phosphate group
- four bases: A, C, G, T
- one strand of DNA is a chain of nucleotides joined by a strong phosphodiester bond
6
Q
phosphodiester bond
A
- bond formed between phosphate and sugar of adjacent nucleotides (links in growing chain)
7
Q
State which nucleotide bases pair with each other:
A
- A base pairs with T via two hydrogen bonds
- G base pairs with C via three hydrogen bonds
8
Q
DNA replication
A
- entire genome is copied in the nucleus prior to cell division (mitosis or meiosis)
- has DNA repair systems, but can still encounter mistakes in copying process
9
Q
Mutation
A
- mistakes in the copying process of DNA (mitosis or meiosis)
- creates variation from one individual to the next in a population
- some are harmful and some are beneficial; most are neutral
10
Q
Describe the process of DNA replication
A
- semi-conservative
- double stranded DNA unwinds from tight conformation, hydrogen bonds between complimentary bases break, strands separate
- each parent strand here serves as the template for a new growing DNA strand, based on complimentary base pairing
11
Q
Describe the structure of RNA
A
- single strand/chain of nucleotides
- nucleotides composed of base, sugar, and phosphate group
- four bases: A with U(replaces T), G with C
12
Q
Transcription
A
- the process of making RNA in the cell, begins in nucleus
- he first step of Transcription involves separation of the DNA double helix into two strands
- unlike DNA construction, only one strand of DNA acts as template for RNA
- RNA strand processed and sent into cytoplasm as mRNA
13
Q
Describe general Translation
A
- makes a protein (string of amino acids joined by a peptide bond; all proteins made from 20 amino acids)
- involves interaction between mRNA, tRNA, and ribosome proteins
- Genetic Code developed to interpret the info in DNA that leads to proteins
14
Q
Describe the process of translation for mRNA
A
- mRNA can be copied from one strand of DNA and grouped into non overlapping triplet nucleotides (codons!!)
- the codons are interpreted by a Genetic Table that lists the codons associated with the various amino acids
- more than one codon can specify the same amino acid
15
Q
degenerate
A
- more than one codon specifies the same amino acid
16
Q
tRNA
A
- transfer RNA
- 61 unique molecules, unique by its anticodon sequence(three nucleotide sequence that complimentary to each codon)
- each tRNA also carries one of the 20 amino acids
17
Q
Describe translation process of tRNA and mRNA
A
- a tRNA will bind to the mRNA via base pairing between the anticodon (on tRNA) and the codon (on mRNA)
- occurs on the ribosome
- tRNA will give specific amino acid it carries (first codon in any protein AUG)
- tRNA carries UAC, carries amino acid Methionine (first protein in any organism)
18
Q
Methionine in translation
A
- starts chain of amino acids/protein
- translation continues along mRNA on ribosome, one codon at a time
- process stops when ribosome encounters STOP codon (three exist)
- then ribosome and mRNA separate, translation stops
