Cell Biology and Genetics Lecture Notes

A collection of vocabulary flashcards for key concepts in cell biology and genetics based on lecture notes.

Phospholipid

Amphipathic molecule with a hydrophilic phosphate head and two hydrophobic fatty acid tails, forming the bilayer structure of cell membranes.

Fluid Mosaic Model

Membrane model describing a fluid phospholipid bilayer with embedded proteins that move laterally.

Cholesterol

Regulates membrane fluidity by preventing tight packing at low temperatures and restraining movement at high temperatures.

Integral Protein

Protein embedded within the membrane, often spanning the bilayer.

Peripheral Protein

Protein attached to the membrane surface.

Selective Permeability

Property allowing some substances to cross more easily than others.

Active Transport

Energy-requiring movement of substances against their concentration gradient using ATP.

Sodium-Potassium Pump

Pumps 3 Na+ out and 2 K+ in, generating membrane potential.

Membrane Potential

Voltage across a membrane due to ion differences.

Electrochemical Gradient

Combination of concentration and charge differences across the membrane.

Electrogenic Pump

Pump that generates voltage across the membrane.

Proton Pump

Moves H+ ions to create a gradient used for ATP synthesis.

Cotransport

Transport where one solute drives the movement of another.

Exocytosis

Vesicles fuse with the membrane to release substances.

Endocytosis

Cell takes in substances by forming vesicles.

Phagocytosis

Cell engulfs large particles.

Pinocytosis

Cell takes in extracellular fluid.

Receptor-Mediated Endocytosis

Specific uptake via receptor proteins.

LDL

Cholesterol-carrying particles taken into cells.

Hypercholesterolemia

Condition of high LDL due to receptor defects.

Transformation

Uptake of foreign DNA by a cell.

Griffith Experiment

Showed bacteria can be transformed by DNA from dead cells.

Hershey-Chase Experiment

Used radioactive labels to prove DNA (not protein) is genetic material.

DNA Double Helix

Two antiparallel strands held by hydrogen bonds between bases.

Semiconservative Replication

Each DNA molecule has one old and one new strand.

Helicase

Unwinds the DNA helix.

Topoisomerase

Prevents DNA supercoiling ahead of the fork.

Primase

Synthesizes RNA primers.

DNA Polymerase

Adds nucleotides to the growing strand (5'→3').

Leading Strand

Synthesized continuously.

Lagging Strand

Synthesized in fragments.

Okazaki Fragments

Short DNA segments on the lagging strand.

DNA Ligase

Joins fragments together.

Telomeres

Protective ends of chromosomes.

Telomerase

Extends telomeres in germ cells.

Chromatin

DNA-protein complex.

Histones

Proteins that DNA wraps around.

Nucleosome

Unit of DNA wrapped around histones.

Euchromatin

Loosely packed, active DNA.

Heterochromatin

Densely packed, inactive DNA.

Gene Expression

Process of using DNA information to make proteins.

Transcription

Process of synthesizing mRNA from DNA.

Translation

Process of synthesizing protein from mRNA.

mRNA

Messenger RNA carrying genetic code.

Ribosome

Site of protein synthesis.

Codon

Three-base sequence coding for an amino acid.

Template Strand

DNA strand used to make RNA.

Coding Strand

DNA strand matching RNA sequence.

RNA Polymerase

Synthesizes RNA from DNA template.

Promoter

DNA region where transcription begins.

TATA Box

Promoter sequence signaling start site.

Initiation

Beginning of transcription.

Elongation

RNA strand grows.

Termination

RNA polymerase detaches.

RNA Splicing

Removal of introns from RNA.

Introns

Noncoding regions removed from RNA.

Exons

Coding regions retained in RNA.

tRNA

Transfers amino acids to the ribosome.

Anticodon

tRNA sequence complementary to codon.

A Site

Incoming tRNA binds.

P Site

tRNA holding the growing chain.

E Site

Exit site for tRNA.

Point Mutation

Single base change in DNA.

Silent Mutation

Mutation with no amino acid change.

Missense Mutation

Mutation resulting in a different amino acid.

Nonsense Mutation

Mutation that introduces a stop codon.

Frameshift Mutation

Mutation that alters the reading frame.

Law of Segregation

Alleles separate during gamete formation.

Law of Independent Assortment

Genes assort independently during gamete formation.

Homozygous

Organism with two identical alleles for a trait.

Heterozygous

Organism with two different alleles for a trait.

Dominant

Allele that is expressed.

Recessive

Allele that is masked.

Punnett Square

Diagram used to predict offspring genotypes.

Multiplication Rule

Probability of two independent events equals the product of their probabilities.

Addition Rule

Probability of either of two mutually exclusive events equals the sum of their probabilities.

Incomplete Dominance

Condition where a blend of traits is expressed.

Codominance

Condition where both alleles are expressed.

Pleiotropy

One gene affects multiple traits.

Epistasis

One gene affects the expression of another gene.

Polygenic Inheritance

Multiple genes collectively influence a trait.

Pedigree

Diagram showing family inheritance patterns.

Cystic Fibrosis

Recessive genetic disorder affecting the lungs.

Sickle Cell Disease

Recessive genetic blood disorder.

Achondroplasia

Dominant genetic disorder causing dwarfism.