Biology Notes.docx

Essential Nutrients

Substances that an organism cannot synthesize and must absorb in preassembled form, including certain amino acids, fatty acids, vitamins, and minerals.

Essential Amino Acids

Amino acids that an animal cannot synthesize and must obtain from food in prefabricated form, such as isoleucine, leucine, lysine, and others.

Essential Fatty Acids

Unsaturated fatty acids that animals need but cannot produce, crucial for synthesizing cellular components and other functions.

Vitamins

Organic molecules required in small amounts in the diet, serving various functions like enzyme substrates and coenzymes.

Dietary Minerals

Inorganic nutrients needed in small quantities, such as iron and sulfur, for various physiological functions.

Malnutrition

Resulting from a diet lacking essential nutrients or sufficient chemical energy, affecting one in four children globally.

Ingestion

The act of eating, the initial stage of food processing in animals.

Digestion

The breakdown of food into absorbable molecules, involving mechanical and chemical processes.

Absorption

The uptake of small nutrient molecules by an organism's body, a crucial stage in food processing.

Elimination

The passing of undigested material out of the body, the final stage of food processing in animals.

Restriction Site

A specific sequence on a DNA strand recognized and cut by a restriction enzyme

Sticky end

Single-stranded end of a double-stranded restriction fragment

Gel Electrophoresis

Technique for separating nucleic acids or proteins based on size and charge

Polymerase Chain Reaction

Technique for amplifying DNA in vitro using specific primers and DNA polymerase

RNA polymerase

Enzyme linking ribonucleotides into an RNA chain during transcription

Promoter

Specific DNA sequence binding RNA polymerase to start transcribing RNA

Terminator

DNA sequence marking the end of a gene and signaling RNA polymerase to release RNA

Transcription Unit

DNA region transcribed into an RNA molecule

Transcription factors

Regulatory proteins binding to DNA affecting gene transcription

RNA Splicing

Removal of introns and joining of exons in eukaryotic RNA processing

Spliceosome

Complex splicing RNA by interacting with intron ends and joining exons

Alternative RNA splicing

Eukaryotic gene regulation producing different mRNA from the same transcript

Transfer RNA (tRNA)

RNA translating nucleic acid to protein by carrying specific amino acids

Anticodon

Nucleotide triplet on tRNA base-pairing with mRNA codon

Ribosomal RNAs (rRNA)

RNA molecules forming ribosomes with proteins

DNA replication

Copying DNA, including semiconservative model and origins of replication

Helicases

Enzymes untwisting DNA double helix at replication forks

DNA Polymerases

Enzymes elongating new DNA strands during replication

Mismatch Repair

Cellular process removing and replacing incorrectly paired nucleotides

Telomeres

Repetitive DNA at eukaryotic chromosome ends protecting genes during replication

Operon

Genetic unit in bacteria with promoter, operator, and coordinately regulated genes

Repressor

Protein inhibiting gene transcription by binding to DNA

Regulatory Gene

Gene coding for a protein controlling transcription of other genes

Corepressor

Small molecule binding to a repressor protein to switch an operon off

Inducer

Small molecule binding to a repressor protein to switch an operon on

Activator

Protein that binds to DNA and stimulates gene transcription

Differential gene expression

Expression of different sets of genes by cells with the same genome

Chromatin organization

Packs DNA into a compact form and regulates gene expression

Heterochromatin

Densely arranged chromatin where genes are usually not expressed

Euchromatin

Less condensed chromatin available for transcription

Histone Acetylation

Attachment of acetyl groups to histone proteins

DNA methylation

Presence of methyl groups on DNA bases, affecting gene expression

Epigenetics

Study of inherited traits not involving changes in the nucleotide sequence

Control elements

Noncoding DNA segment regulating gene transcription by binding transcription factors

Enhancers

DNA segment with multiple control elements, regulating gene transcription from a distance