Comprehensive BIOS 255 Week 7 Study Guide for Biology, Cell, and System Anatomy Questions & answers

Cation

Positive charge, fewer electrons than protons

Anion

Negative charge, MORE electrons than protons

Isotope

Same element, different neutron count

Isomer

Same molecular formula, different structure

Synthesis (anabolic)

Smaller → larger molecules

Decomposition

Larger → smaller molecules

Exchange

Two compounds swap components

Ionic/Covalent

Bond type determines reaction chemistry

Acid

H⁺ donor

Base

H⁺ acceptor

pH scale

0-14; 7 = neutral

Buffers

Resist rapid pH change

Enzyme activity

Is pH- and temperature-dependent

Carbohydrates

Energy; simple sugars (monosaccharides)

Lipids

Fatty acids + glycerol; fat-soluble vitamins

Proteins

1°, 2°, 3°, 4° structural organization — ONLY macromolecule with all four levels

Nucleic acids

DNA/RNA; genetic info

Nucleus

Genetic control center

Mitochondria

ATP production

Ribosomes

Protein synthesis

Golgi apparatus

Packages/ships proteins

Lysosomes

Digestion/waste

ER (rough)

Protein synthesis

ER (smooth)

Lipids

Centrioles

Cell division

Diffusion

High → low concentration (passive)

Osmosis

Water movement across membrane

Facilitated transport

Carrier proteins, passive

Active transport

Requires ATP, against gradient

Filtration

Pressure-driven

Mitosis

2 genetically IDENTICAL daughter cells

Meiosis

4 genetically unique cells (sex cells only)

Binary fission

Prokaryotic cell division

Interphase

G1 → S (DNA replication) → G2

Mitotic phases

Prophase, Metaphase, Anaphase, Telophase

Cytokinesis

Cytoplasm division follows mitosis

Isotonic

Cell stays same — no net water movement

Hypotonic

Cell swells → may lyse (less solute outside)

Hypertonic/hyperosmotic

Cell shrinks/crenates (more solute outside)

Stratum basale

Deepest; mitosis occurs here; stem cells

Stratum spinosum

Keratin production begins

Stratum granulosum

Keratinization intensifies

Stratum lucidum

Only in thick skin (palms/soles)

Stratum corneum

Outermost; dead, keratinized cells — forms calluses

Eccrine sweat glands

Thermoregulation; found everywhere

Apocrine sweat glands

Axilla/groin; activate at puberty

Sebaceous glands

Produce SEBUM (oily/waxy); lubricate skin & hair

Ceruminous glands

Ear canal; produce cerumen (earwax)

Mammary glands

Modified sweat glands; produce milk

Skin Functions

Protection, thermoregulation, vitamin D synthesis, sensation, excretion

Connective tissue fibers

Collagen (strength, most abundant), Elastic (stretch/recoil), Reticular (scaffolding)

Albumin

Plasma protein (transport/osmotic pressure) — NOT a structural fiber

Long bones

Femur, humerus, tibia, fibula

Short bones

CARPALS, TARSALS — wrist and ankle

Flat bones

Sternum, scapula, skull bones

Irregular bones

Vertebrae, facial bones

Osteoblasts

BUILD bone; secrete extracellular matrix

Osteoclasts

BREAK DOWN bone (resorption)

Osteocytes

Mature bone cells; maintain matrix

Osteogenic/osteoprogenitor cells

Stem cells; become osteoblasts

Diaphysis

Shaft

Epiphysis

Ends

Epiphyseal plate (growth plate)

Cartilage; LENGTHENS bone during growth

Periosteum

Outer covering (appositional growth)

Endosteum

Inner lining; lines medullary cavity

Axial skeleton

Skull, vertebral column, rib cage (80 bones)

Appendicular skeleton

Limbs, girdles (126 bones) — includes femur, humerus

Ball-and-socket joints

Shoulder (glenohumeral) & hip — MOST movement

Hinge

Elbow, knee

Pivot

Atlas/axis

Saddle

Thumb

Gliding

Wrist

Endomysium

Wraps INDIVIDUAL muscle fibers

Perimysium

Wraps fascicles (bundles of fibers)

Epimysium

Wraps entire muscle

Troponin

BINDS CALCIUM → initiates contraction; moves tropomyosin

Tropomyosin

Covers myosin-binding sites at rest

Actin

Thin filament; sliding filament target

Myosin

Thick filament; power stroke motor

Calcium

Stored in sarcoplasmic reticulum

Isometric

Muscle generates force, NO change in length

Isokinetic

Constant speed; resistance changes

Hamstrings

Biceps femoris, semimembranosus, semitendinosus

Quadriceps

Vastus lateralis/medialis/intermedius + rectus femoris

Triceps surae

Gastrocnemius + soleus

NMJ

Acetylcholine (ACh) released to initiate contraction

NMJ neurotransmitter

ACh.

Voltage-gated channels

Open/close in response to membrane potential change.

Ligand-gated channels

Open when neurotransmitter binds.

Mechanically-gated channels

Respond to PRESSURE or STRETCH.

Leak channels

Always open; maintain resting potential.

Resting potential

~−70 mV; Na⁺ out, K⁺ in (Na⁺/K⁺ ATPase).

Threshold potential

~−55 mV; point of no return.

Depolarization

Na⁺ rushes IN → membrane becomes MORE POSITIVE.

Repolarization

K⁺ rushes out → returns toward resting.

Hyperpolarization

Briefly more negative than resting.

Refractory period

Absolute (no AP) → relative (strong stim only).

Sympathetic nervous system

Fight-or-flight; epinephrine/norepinephrine; ↑ HR, ↑ BP, ↑ glucose; thoracolumbar origin.

Parasympathetic nervous system

Rest-and-digest; acetylcholine; conserves energy; craniosacral origin; vagus nerve (CN X) = major parasympathetic nerve.

Frontal lobe

Motor control, personality, executive function.