dna replication, protein synthesis, cellular respiration

DNA

deoxyribonucleic acid, genetic material within chromosomes of nucleus, mitochondria, and chloroplasts

RNA

ribonucleic acid, found in cytoplasm, used for protein synthesis

Components of a Nucleotide

subunits that make up long strands of DNA and RNA, composed of phosphate group, pentose sugar, nitrogenous bases

Pentose Sugar in DNA

in DNA, is deoxyribose

Pentose Sugar in RNA

in RNA, is ribose with OH

Nitrogenous Bases

different molecular structures, but all contain nitrogen

Purines

double ring structure, guanine and adenine

Pyrimidines

single ring structure, cytosine, thymine (DNA), uracil (RNA)

Nucleic Acid Condensation Reaction

nucleotides join together through covalent bonds, linked into single strand through condensation reaction

Sugar Phosphate Backbone

in DNA, on outside, nitrogenous bases on inside, two strands are held together by hydrogen bonds

Complementary Base Pairing

Adenine + Thymine, Cytosine + Guanine, allows genetic information to be replicated and expressed

DNA Replication

guanine can only bind to cytosine, adenine can only bind to thymine on opposite strands by hydrogen bonding

DNA Structure

DNA as a double helix, strands are antiparallel, one strand runs 5' to 3', other runs 3' to 5'

Gene

specific segment of DNA that codes for the making of a protein

Codon

three nucleotides in a gene represent a piece of information

DNA vs RNA Bases

DNA bases: ATCG, RNA bases: AUCG

DNA vs RNA Sugar

DNA sugar: deoxyribose, RNA sugar: ribose

DNA vs RNA Number of Strands

DNA has 2 strands, RNA has 1 strand

DNA Replication Accuracy

must replicate accurately so its genetic code can be passed on to daughter cells during cell division

Meselson-Stahl Experiment

used 15N (rare isotope of nitrogen, heavier than 14N), results suggested that DNA replication was semi-conservative

Mechanisms of DNA Replication Stage One

separation of the double helix into two single strands by helicase

Mechanisms of DNA Replication Stage Two

free-floating nucleotides are used to create complementary pairs on each single strand by DNA polymerase

Polymerase Chain Reaction (PCR)

laboratory technique that amplifies a specific segment of DNA

PCR Components

primers: short polymers of 15-20 nucleotides, taq polymerase: polymerase from thermophilic bacteria

PCR Process Denaturation

the mixture is heated to a temperature between 92-98℃ to break the hydrogen bonds holding the two strands of DNA together

PCR Process Annealing

the mixture is cooled to between 50-65℃, allowing the primers to bind with nucleotides on both strands

PCR Process Elongation

the Taq polymerase catalyses the building of new DNA strands by extending the primers

DNA from botanical evidence

Can be used to establish the genetic relatedness.

PCR

A method used to amplify and copy small samples of DNA repeatedly.

Gel Electrophoresis

Technique used to separate DNA fragments based on their size.

DNA migration in gel

Longer DNA fragments travel shorter distances while shorter DNA fragments travel longer distances.

DNA profiling

The banding pattern produced in the gel is compared.

Protein synthesis

The process where proteins are linear sequences of amino acids condensed together.

Transcription

The process of synthesizing RNA molecules from DNA in the nucleus.

mRNA

RNA exported to the cytoplasm after creation from DNA.

Translation

The process where RNA combines with ribosomes to synthesize a protein.

Initiation in Transcription

RNA polymerase attaches to a DNA sequence called the promoter.

Elongation in Transcription

RNA polymerase synthesizes an RNA transcript and separates the DNA double helix.

Termination in Transcription

RNA polymerase reaches a transcription terminator signal, releasing the RNA strand.

Post-transcriptional modification

Necessary in eukaryotes to form mRNA, involving capping, polyadenylation, and splicing.

Types of RNA in Translation

Includes messenger RNA, transfer RNA, and ribosomal RNA.

Ribosomes

Composed of large and small subunits, they catalyze peptide bonds between amino acids.

Genetic Code

Set of rules by which information encoded in mRNA sequences is converted into proteins.

Codons

Sequences of three bases in mRNA that determine the amino acid sequence for proteins.

Degenerate code

Each amino acid may have more than one codon, allowing for mutations.

Universal code

All living organisms share the same genetic code.

Main events in Translation

Involves mRNA binding to ribosome, tRNA binding, and peptide bond formation.

Transfer RNA

Single strand of nucleotides that transports amino acids to the ribosome.

Anticodon

Triplet base sequence on tRNA that is complementary to the codon of mRNA.

Mutations

Permanent changes to RNA that can affect protein structure.

Point mutation

Involves a change in only one base of a gene.

Sickle cell anemia

Blood disorder caused by a single base substitution mutation in hemoglobin.

Cellular respiration

Process in which energy is made available from nutrients in cells.

ATP

A nucleotide with three phosphates linked together, representing stored chemical energy.

Aerobic respiration

Series of reactions where glucose is broken down in the presence of oxygen to produce ATP.

Anaerobic respiration

Glucose can be broken down without using oxygen to yield a small quantity of ATP.

Factors affecting cellular respiration

Temperature, carbon dioxide concentration, oxygen concentration, glucose concentration, and type of cell.