Lecture 2: DNA, RNA, protein Flashcards
Deoxyribonucleic acid (DNA) does what
Stores genetic information in its sequence
Ribonucleic acid (RNA) does what
Decodes genetic information into instructions for building proteins
DNA is
DNA is a polymer
Repetition of a monomer
Nucleotides are building blocks
Polynucleotide chains
Nucleotides are determined by
Phosphate group
Sugar
Nitrogenous base
Four types of nucleotides in DNA
Four types of nucleotides depending on the nitrogenous base linked to the sugar
A- adenine
C-cytosine
G- guanine
T- thymine
DNA structure is
Double helix
Alternating sugar and phosphate groups form the sides
Sugar – phosphate backbone
Phosphate of one nucleotide links to the sugar of the adjacent nucleotide
Base pairing of nucleotides in DNA
A pairs with T
C pairs with G
Pairing produces weak attractive forces between opposite bases
Holds polynucleotide chains together
Hydrogen bonds
Base pairing occurs when the two polynucleotide chains are lined up in opposite directions
Anti-parallel
Packaging of DNA includes
DNA associates with proteins to form chromosomes
DNA double helix coils around histone proteins – called nucleosome
Further folded into a thicker fiber
Additional packaging achieves chromosome structure for mitosis and meiosis
Supercoiling
DNA replication is
Prior to cell division, DNA must be copied in order to provide each daughter cell with the entire genome
Requires extensive and accurate DNA replication
Key resides in complementary base pairing
Strands separate
Each strand acts as a template to produce a complementary strand
Semi-conservative replication
What happens by DNA replication
Two new molecules identical to the first are produced
Each has 1 strand from the original molecule
Each has one newly made strand
Central dogma is
DNA → RNA → Protein
Transcription is
Coded information within DNA is copied into a complementary RNA sequence
Translation is
RNA associates with ribosomes
The synthesis of the encoded protein molecule
Information transfer is located in
The DNA and the site of protein synthesis are physically separated
DNA is located in the nucleus
The information carrier is nucleus
Information transfer can cause
Protein synthesis occurs at ribosomes within the cytoplasm
Most genes contain the information for the production of a specific protein
Directly or indirectly leads to the expression of a particular phenotype
Purpose of genetic material is to encode the production of proteins in the correct cell, at the correct time, and in the correct amount