Bio of Allied Health Exam 2

Four levels of Animal Bodily Organization

Cells, Tissues, Organs, Organ Systems

Cells

Basic unit of structure and function in living things

Tissues

Groups of similar cells performing a specific function

Organs

Structures composed of multiple tissue types that perform specific tasks

Organ Systems

groups of organs that work together to carry out major body functions 

Four types of Animal Tissues

Epithelial, Connective, Muscle, Nervous Tissue

Epithelial Tissue

covers body surfaces and lines organs/cavities; functions in protection, absorption, secretion

Connective Tissue

Provides support, binds tissues, stores energy, and transports materials

Muscle Tissue

Responsible for movement, contracts to produce motion

Nervous Tissue

Transmits electrical impulses for communication and control 

5 types of Connective Tissue

Loose, Fibrous (dense), adipose, cartilage, bone

Loose Connective tissue

holds organs in place, provides cushioning

fibrous (dense) connective tissue

forms tendons and ligaments, very strong

Adipose tissue

Stores fat for energy and insulation

Cartilage

provides flexible support and cushioning (nose, ears, joints)

Bone

rigid structure for protection and support, attached to bones

3 types of muscle tissue

Skeletal, cardiac, smooth muscle

Skeletal Muscle

Voluntary movement, striated, attached to bones

Cardiac Muscle

Involuntary, striated, found only in the heart, pumps blood

Smooth muscle 

Involuntary, non-striated, found in walls or organs (stomach, intestines)

Two main cellular components of nervous tissue

Neurons and Glial Cells

Neurons

transmit electrical and chemical signals, functional units of the nervous system

Glial Cells 

support, nourish, and protect neurons 

Integumentary System

skin, protection, temperature regulation

Skeletal

support, movement, protection, blood cell production

Muscular

movement, posture, heat production

Endocrine

hormone production, long term regulation

Nervous

control and communication via electrical signals

Cardiovascular

transports blood, nutrients, gases, wastes

Lympathic/Immune

defends against infection, returns fluid to blood 

Respiratory

gas exchange (oxygen in, carbon dioxide out)

Digestive

breaks down food, absorbs nutrients

Reproductive

produces gametes and hormones for reproduction

Homeostasis

maintaining internal stability despite external changes

Set point

the normal or target value for a physiological variable Nega

Negative Feedback Loop

brings back to set point

Positive Feedback Loop

further from set point (contractions during birth)

Regulate

maintain constant internal conditions regardless of the environment

Conform

Internal conditions change with the external environment (reptiles)

Endotherms

generate internal heat, active in varied temperatures, energy costly

ectotherms

rely on external heat sources, lower energy use but limited activity in the cold

Osmoregulation in Humans 

Kidneys, filter blood, retain water/salt, excrete waste 

Prokaryotic Cells

small, no nucleus or membrane-bound organelles. DNA is free in the cytoplasm. (bacteria)

Eukaryotic Cells

larger, more complex cells with nucleus and membrane-bound organelles (plants, fungi, protists)

Similarities between pro and eukaryotic cells 

both have DNA, plasma membrane, cytoplasm, and ribosomes 

Plasma membrane function

controls what enters and exists the cell, provides protection and structure

Cytoplasm function

jelly-like fluid that fills the cell and holds organelles in place

DNA function 

stores genetic information for growth, development, and reproduction 

Ribosomes function

sites of protein synthesis; found in both cell types

Endosymbiosis Theory

eukaryotic cells formed when larger prokaryotes engulfed smaller ones (like mitochondria and chloroplasts) which lived symbiotically

Invagination Theory

Eukaryotic organelles formed from inward folding of the plasma membrane

Phospholipid Role

forms the lipid bilayer with hydrophillic heads and hydrophobic tails

Amphipathic Definition 

molecules with both hydrophillic (water-loving) and hydrophobic (water-fearing) parts 

Phospholipid Orientation

Hydrophillic heads face outward toward water; hydrophobic tails face inward- forms a stable bilayer in aqueous environments

Fluid Mosaic Model

describes the membrane as flexible (fluid) with proteins and molecules embedded within it (mosaic)

Cholestrol Role

maintains membrane fluidity and stability; prevents it from becoming too rigid

Integral proteins

span the membrane, transport molecules or relay signals

Peripheral proteins

attached to surface, used for signaling or cell recognition

transport proteins

help move substances across the membrane

receptor proteins

bind signaling molecules to trigger a response

enzymatic proteins 

catalyze chemical reactions on the membrane surface 

solute

substance being dissolved

solvent

substance doing the dissolving (usually water)

solution

a homogeneous mixture of solute and solvent

Simple diffusion, molecules, movement, proteins, energy, includes 

Molecules: small, nonpolar (O₂, CO₂).

• Movement: high → low concentration.

• Proteins: not required.

• Energy: not required.

• Includes osmosis, the diffusion of water.

Facilitated Diffusion molecules, movement, proteins, energy, includes 

• Molecules: larger or polar (glucose, ions).

• Movement: high → low concentration.

• Proteins: required (channel or carrier).

• Energy: not required.

Active Transport molecules, movement, proteins, energy, includes

• Molecules: ions or substances moving against gradient.

• Movement: low → high concentration.

• Proteins: required.

• Energy: required (ATP).

Isotonic

Equal solute concentration; no net water movement.

Hypotonic

Lower solute outside; water moves in; animal cells may burst (lyse), plant cells become turgid.

Hypertonic

Higher solute outside; water moves out; animal cells shrink (crenate), plant cells plasmolyze.

Endocytosis 

Cell takes in large materials by engulfing them in a vesicle

Exocytosis

Cell releases materials by fusing a vesicle with the membrane.

Nucleus function

Houses DNA; controls cell activities. Contains nuclear envelope, pores, chromatin, and nucleolus (makes ribosomes).

Cilia & Flagella

Hair-like (cilia) or tail-like (flagella) structures for movement and fluid flow.

Cytoskeleton

Network of fibers providing structure, shape, and intracellular transport.

Mitochondria

Site of ATP (energy) production through cellular respiration; contains its own DNA—evidence of endosymbiosis.

Lysosomes

Contain digestive enzymes to break down waste and worn-out organelles.

Endomembrane system main components

Nuclear envelope → Endoplasmic Reticulum (ER) → Golgi Apparatus → Vesicles → Plasma Membrane.

Endomembrane system molecule movement

Proteins made in RER → modified in Golgi → transported via vesicles → secreted or used in cell.

Rough ER

Has ribosomes; synthesizes and folds proteins.

Smooth ER

No ribosomes; makes lipids, detoxifies, stores calcium.

Golgi Apparatus

Modifies, sorts, and packages proteins and lipids for transport.

Cell Wall

Rigid outer layer made of cellulose; provides structure and protection.

Vacuoles

Large central sac that stores water, nutrients, and waste; helps maintain pressure.

Chloroplasts

Site of photosynthesis; converts sunlight into chemical energy; contains its own DNA (supports endosymbiosis theory).

Photosynthesis

Process by which plants, algae, and some bacteria capture light energy and convert it into chemical energy (glucose).

Provides the energy and oxygen used by organisms in cellular respiration.

Cellular Respiration

Cells break down glucose to produce ATP, releasing CO₂ and H₂O; the energy from food flows through ecosystems via this process.

Energy

The capacity to do work or cause change.

Kinetic energy

Energy of motion (e.g., moving muscles, flowing water).

Potential energy

Stored energy due to position or structure (e.g., chemical bonds in food).

First Law of Thermodynamics

Energy cannot be created or destroyed, only transformed.
Example: Food energy → heat + motion.

Second Law of Thermodynamics

Energy transformations increase entropy (disorder) of the universe.
Example: Heat loss from metabolism.

Metabolism

All chemical reactions that occur within an organism; includes both energy-releasing (catabolic) and energy-storing (anabolic) processes.

ATP (Adenosine Triphosphate)

Main energy currency of the cell; stores energy in high-energy phosphate bonds.

Structure of ATP

Adenine (base) + ribose (sugar) + 3 phosphate groups.

ATP Function

Provides energy for cellular work (movement, active transport, biosynthesis).

ATP Formation (Energy Storage)

Energy from food is used to add a phosphate group to ADP → ATP.

ATP Breakdown (Energy Release)

ATP loses a phosphate (hydrolysis) → ADP + Pi + energy for cell work.

Cell Respiration process

Glucose is broken down to produce ATP through a series of metabolic steps; oxygen is required for most stages.

Provides usable energy (ATP) that powers all cellular activities.

4 major stages of cellular respiration

1⃣Glycolysis
2⃣ Pyruvate Oxidation (Link Reaction)
3⃣ Citric Acid Cycle (Krebs Cycle)
4⃣ Electron Transport Chain