Stage 2 Bio - DNA and proteins

DNA

Deoxyribonucleic acid, genetic material in cells.

Chromosome

Structure containing DNA, genes, and proteins.

Double Helix

Twisted ladder structure of DNA.

DNA Helicase

Enzyme that unwinds DNA during replication.

Semi-Conservative Replication

Each new DNA molecule has one old strand.

Nucleotide

Building block of DNA and RNA.

Thymine (T)

Nitrogenous base pairing with Adenine (A).

Introns

Non-coding regions of a gene.

Exons

Coding regions of a gene that are expressed.

Deoxyribose Sugar

Sugar component of DNA nucleotides.

RNA

Ribonucleic acid, involved in protein synthesis.

Uracil (U)

Nitrogenous base in RNA, replaces Thymine.

Ribose Sugar

Sugar component of RNA nucleotides.

DNA Polymerase

Enzyme that synthesizes new DNA strands.

Gene

Segment of DNA coding for polypeptides.

Locus

Specific location of a gene on a chromosome.

Chromatin

Uncondensed form of DNA in non-dividing cells.

Chromatids

Condensed DNA strands during cell division.

Ligase

Enzyme that seals DNA sugar-phosphate backbone.

mRNA

Messenger RNA, carries genetic information to ribosomes.

tRNA

Transfer RNA, brings amino acids to ribosomes.

Ribosome

Cellular structure where protein synthesis occurs.

mRNA

Messenger RNA that carries genetic information.

Polypeptide chain

A sequence of amino acids linked by peptide bonds.

Codon

Three mRNA bases coding for one amino acid.

Amino acid

Building blocks of proteins; 20 types exist.

rRNA

Ribosomal RNA, a component of ribosomes.

tRNA

Transfer RNA that brings amino acids to ribosomes.

Transcription

Process of copying DNA into mRNA.

Translation

Process of converting mRNA into a polypeptide.

Template strand

Strand used to synthesize mRNA during transcription.

Coding strand

Strand with same sequence as mRNA (except T).

Primary structure

Linear sequence of amino acids in a polypeptide.

Secondary structure

Folding patterns like alpha helices and beta sheets.

Tertiary structure

3D shape of a protein due to interactions.

Quaternary structure

Complex of multiple polypeptide chains.

Enzyme

Protein that catalyzes biochemical reactions.

Active site

Region on enzyme where substrate binds.

Induced fit model

Enzyme changes shape to fit substrate better.

Optimum temperature

Temperature at which enzyme activity is highest.

Inhibitors

Substances that decrease enzyme activity.

Competitive inhibitor

Molecule resembling substrate that blocks active site.

Activation energy

Energy needed to start a chemical reaction.

Rate of reaction (ROR)

Speed at which reactants turn into products.

Inhibitor

Substance that competes with substrate for enzyme's active site.

Reversible Inhibition

Inhibitor can detach from enzyme, restoring function.

Concentration Effect

Higher inhibitor concentration increases binding likelihood.

Optimum Temperature

Temperature range where enzyme activity is maximized.

Denatured Enzyme

Enzyme loses structure, preventing substrate binding.

Point of Saturation

Maximum substrate concentration where enzyme activity plateaus.

Activation Energy

Energy required to initiate a chemical reaction.

Induced Fit Model

Enzyme changes shape to accommodate substrate binding.

Transition State

Temporary state during enzyme-substrate interaction.

Irreversible Denaturation

Permanent loss of enzyme function due to extreme conditions.

Optimum pH

pH range where enzyme activity is highest.

Allosteric Inhibitor

Binds away from active site, altering enzyme shape.

Rate of Reaction (ROR)

Speed at which reactants convert to products.

Kinetic Energy

Energy of motion affecting enzyme-substrate collisions.

Epigenetic Modification

DNA changes affecting gene expression without sequence alteration.

Transcription Factors

Proteins regulating gene expression by activating or repressing.

Methylation

Addition of methyl group, silencing gene expression.

CpG Site

Region in DNA where methylation commonly occurs.

Phenotypical Expression

Observable traits influenced by genetic and environmental factors.

Environmental Factors

External influences causing epigenetic changes in genes.

Identical Twins Phenotype

Same DNA, different environments lead to varied gene expression.

Transcription Factors

Proteins that bind to promoter regions to initiate transcription.

Promoter Region

DNA segment upstream of a gene where transcription factors bind.

Epigenetic Changes

Modifications affecting gene expression without altering DNA sequence.

Methylation

Addition of methyl groups affecting gene expression and differentiation.

Cell Differentiation

Process where stem cells specialize into specific cell types.

Stem Cells

Undifferentiated cells capable of becoming specialized cell types.

Tumor Suppressor Genes

Genes that normally inhibit cell division and tumor formation.

Proto-oncogenes

Normal genes that can become oncogenes when mutated.

Gene Silencing

Inactivation of gene expression, often through methylation.

Methylated Gene

Gene with added methyl groups, typically not expressed.

Acetylated Histones

Histones that allow loose DNA packing, promoting gene expression.

Deacetylated Histones

Histones causing tight DNA packing, inhibiting gene expression.

Somatic Cells

Body cells that undergo mitosis and inherit methylation patterns.

Mitotic Heritability

Transmission of methylation patterns during cell division.

Mutation

Permanent change in nucleotide sequence of DNA.

Mutagen

Agent that increases the rate of mutation.

Base Substitution

Replacement of one nucleotide with another in DNA.

Base Insertion/Deletion

Addition or removal of nucleotides altering reading frame.

Phenotypical Expression

Observable traits resulting from gene expression in cells.

Cancer

Uncontrolled cell division often due to gene silencing.

Germ line mutation

Mutation in sex cells, hereditary to offspring.

Somatic mutation

Mutation localized in body cells, not inherited.

Mutation rate

Frequency of mutations in a given timeframe.

Phenotype

Physical appearance influenced by genotype and environment.

Genotype

Genetic makeup of an organism.

PCR

Technique to amplify DNA for analysis.

Primers

Short DNA sequences that initiate DNA synthesis.

Gel electrophoresis

Technique to separate DNA fragments by size.

Short tandem repeats (STRs)

Repetitive non-coding DNA sequences used in profiling.

Forensic DNA profiling

Identifying individuals using unique DNA patterns.

Restriction enzyme

Enzyme that cuts DNA at specific sequences.

Mutagenic chemicals

Substances that increase mutation rates.

Ionizing radiation

High-energy radiation that can cause DNA damage.

DNA fingerprint

Unique pattern of DNA fragments from an individual.

Embryo mutation

Mutation present in every cell of an embryo.