Bio final learning objectives

Function and structure of proteins and lipids

Proteins are amino acid polymers that fold into specific 3D structures for enzymes, transport, signaling, structure, and movement. Lipids are hydrophobic molecules including fats, phospholipids, and steroids that provide energy storage, membrane structure, insulation, and hormones.

Amino acid structure and the five parts

All amino acids have five parts: a central alpha carbon, an amino group (NH2), a carboxyl group (COOH), a hydrogen, and an R-group that determines properties.

Pyrimidines vs purines rings

Pyrimidines have 1 ring (C, T, U). Purines have 2 rings (A, G).

Structure and function of steroids

4 fused carbon rings; function as hormones and regulate membrane fluidity.

Structure and function of triglycerides

Glycerol + 3 fatty acids; long-term energy storage.

Structure and function of phospholipids

Glycerol + 2 fatty acids + phosphate head; form cell membranes.

Nucleotide orientation in DNA double helix

Strands run antiparallel (5'→3' opposite 3'→5'); sugar-phosphate backbone outside, bases inside.

Central dogma

DNA → RNA → Protein.

Six enzymes of DNA replication and their functions

Helicase unwinds DNA; Topoisomerase relieves tension; Primase adds RNA primers; DNA polymerase III extends DNA; DNA polymerase I replaces primers; Ligase connects Okazaki fragments.

Protein structure levels and impacts

Primary: amino acid sequence; Secondary: alpha-helices/beta-sheets; Tertiary: 3D folding; Quaternary: multiple subunits. Changes alter folding and function.

Ribosome structure-function relationship

Ribosomes have large and small subunits that read mRNA and form peptide bonds; structural changes disrupt accurate translation.

Roles of codons, anticodons, aminoacylated tRNAs

Codons are mRNA triplets coding for amino acids; anticodons on tRNA pair with codons; aminoacyl-tRNAs carry the correct amino acids to the ribosome.

Three steps of translation

Initiation (assemble at start codon); Elongation (add amino acids); Termination (release at stop codon).

Micelles vs liposomes vs bilayers

Micelles: single-layer spheres; Liposomes: bilayer spheres with internal fluid; Bilayers: two-layer sheets forming membranes.

Types of active transport and how they work

Primary uses ATP directly (Na+/K+ pump); Secondary uses energy of ion gradients (symport/antiport).

Relationship of anabolic/catabolic, exergonic/endergonic, spontaneous/nonspontaneous

Anabolic builds molecules, requires energy, endergonic, nonspontaneous (+ΔG). Catabolic breaks molecules, releases energy, exergonic, spontaneous (–ΔG).

Energy content of reactants vs products

Higher-energy reactants release energy; higher-energy products require energy input.

Michaelis-Menten plot, Km and Vmax

As substrate increases, rate rises until Vmax. Km is the substrate concentration at half Vmax; low Km means high affinity.

Three digestive hormones and functions

Gastrin: stomach, releases HCl when food enters. Secretin: duodenum, releases bicarbonate when acid arrives. CCK: duodenum, releases bile and pancreatic enzymes when fats enter.

Absorption in small intestine

Villi and microvilli increase surface area; nutrients absorbed via diffusion, facilitated transport, or active transport into blood or lymph.

Four steps of cell signaling

Reception, transduction, response, termination.

Four types of long-distance signaling

Autocrine, paracrine, endocrine, synaptic.

Three receptor types

Ligand-gated ion channels, G-protein coupled receptors (GPCRs), receptor tyrosine kinases (RTKs).

Two types of signal transduction cascades

Phosphorylation cascades amplify signals via kinases; second messenger cascades use molecules like cAMP or Ca2+. Alterations disrupt signal strength.

What happens in mitosis

Mitosis produces two identical diploid cells; phases: prophase, metaphase, anaphase, telophase.

How mitosis differs from binary fission

Binary fission is simpler, no nucleus or chromosomes; DNA is copied and cell splits.

What happens in meiosis

Meiosis I and II produce four genetically unique haploid gametes; includes crossing over and independent assortment.

How the cell cycle works

G1 (growth), S (DNA replication), G2 (prep), M (division); regulated by cyclins/CDKs.

Ventilation, perfusion, circulation

Ventilation: air movement. Perfusion: blood flow across gas exchange surface. Circulation: blood flow throughout body.

How gills function

Countercurrent exchange maximizes O2 uptake by maintaining favorable gradients.

Structure and function of lungs

Bronchi → bronchioles → alveoli; thin moist alveoli allow gas diffusion between air and blood.

Brain regions controlling breathing

Medulla and pons sense CO2, H+, and O2 levels and adjust breathing rate and depth.

Functions of blood

Transport, regulation of temperature and pH, and immune protection.

Functions of the three blood cell types

RBCs carry oxygen; WBCs fight infection; platelets clot blood.

Hemoglobin structure-function

Tetramer with iron-containing heme groups binding O2; affinity affected by pH, CO2, and temperature.

Bohr shift

Low pH and high CO2 shift hemoglobin curve right, causing increased O2 release to tissues.

Circulatory systems of fish

Fish have 2-chambered heart and single circulation loop.

Circulatory systems of amphibians

Amphibians have 3-chambered heart with some mixing of blood.

Circulatory systems of mammals

Mammals have 4-chambered heart and double circulation (systemic + pulmonary).

Path of blood through systemic, pulmonary, and heart

Body → right heart → lungs → left heart → body.

Cardiac output, stroke volume, heart rate

CO = HR × SV; increasing HR or SV increases CO.

SA and AV node functions

SA node is pacemaker; AV node delays signal for coordinated contraction of ventricles.

How nitrogenous waste is produced and removed

Protein metabolism produces ammonia; converted to urea/uric acid; excreted by kidneys.

Concentration gradients in nephron

Cortex has low osmolarity; medulla high osmolarity; gradient pulls water out of filtrate.

ADH-kidney feedback loop

Low water → ADH release → aquaporins added → increased water reabsorption.

Kidney role in BP; RAAS system

Low BP → renin → angiotensin II → aldosterone → increased Na+ and water retention → increased BP.

Three types of glial cells

Astrocytes support neurons; oligodendrocytes/Schwann cells form myelin; microglia act as immune cells.

What happens to membrane potential during AP

Depolarization from Na+ influx, repolarization from K+ efflux; AP arrival triggers Ca2+ entry and neurotransmitter release.

EPSPs and IPSPs

EPSPs depolarize cell (Na+ in); IPSPs hyperpolarize cell (Cl− in or K+ out).

Steps of immune response

Recognition of pathogen, activation of immune cells, response/clearance of pathogen.

Functions of phagocytes

Engulf and digest pathogens.

Functions of granulocytes

Release toxic chemicals, inflammation, defense against parasites.

Functions of B cells

Produce antibodies against specific pathogens.

Functions of T cells

Killer T cells destroy infected cells; helper T cells activate immune responses.