BSC2085 Exam 1

Lectures 1–5

What is the smallest living unit of structure and function?

A cell.

What is a tissue?

A group of similar cells working together to perform a specific function.

Name the four major tissue types.

Epithelial, connective, muscle, nervous.

What is an organ?

Two or more tissues working together to perform a specific function.

What is an organ system?

A group of organs working together to carry out a major function.

Name six levels of organization in the human body.

Chemical → Cellular → Tissue → Organ → Organ System → Organism.

What are the six functions of the human body and their systems?

• Protection → Integumentary

• Communication → Nervous & Endocrine

• Exchange → Urinary, Respiratory, Digestive

• Structure & Movement → Skeletal & Muscular

• Transport → Circulatory & Lymphatic

• Reproduction → Reproductive

Name six factors necessary for life.

Oxygen, Nutrient, Water, Pressure, Temperature, & Waste

What is homeostasis?

The maintenance of a stable internal environment.

What are the three major components of homeostasis?

Receptor: collects info and compares to the setpoint.

Setpoint: the value that the factor is suppose to be (hypothalamus)

An Effector: causes a response in order to return to set point

What is negative feedback? Give an example.

A response that reverses a change to maintain homeostasis. Example: body temperature regulation.

What is positive feedback? Give an example.

A response that amplifies a change until a specific event occurs. Example: childbirth or blood clotting.

What is the difference between equilibrium and steady state?

Equilibrium = balance without energy; Steady state = balance maintained with energy.

What is an atom?

The smallest unit of matter that retains the properties of an element.

What are the major types of atoms in the human body?

Oxygen (O), Carbon (C), Hydrogen (H), Nitrogen (N), Calcium (Ca), Phosphorus (P).

What is a molecule?

Two or more atoms chemically bonded together.

Name the three types of subatomic particles.

Protons (+), Neutrons (0), Electrons (–).

What is the role of protons, neutrons, and electrons?

• Protons: define the element.

• Neutrons: contribute to mass and stability.

• Electrons: determine chemical reactivity and bonding.

How do electrons relate to bonding?

Electrons in the outer shell (valence electrons) determine how atoms bond.

Name the four interactions between atoms.

Covalent bonds, Ionic bonds, Hydrogen bonds, and Polar vs Nonpolar interactions.

How do covalent bonds form?

By sharing electrons between atoms.

What is electronegativity?

The ability of an atom to attract electrons in a covalent bond.

What is the difference between polar and nonpolar bonds?

• Polar: unequal sharing of electrons

• Nonpolar: equal sharing of electrons

How do ionic bonds work?

One atom donates an electron (cation) and another accepts it (anion).

What is an anion?

A negatively charged ion (gains electrons).

What is a cation?

A positively charged ion (loses electrons).

What are salts?

Ionic compounds formed from cations and anions.

What are electrolytes?

Salts that dissociate in water to conduct electricity.

What is the difference between acids and bases?

• Acids: increase H+ concentration

• Bases: decrease H+ concentration

What is pH?

A measure of hydrogen ion concentration; 0–6 = acidic, 7 = neutral, 8–14 = basic.

What are the properties of water?

Polar, good solvent, hydrogen bonding

Why is water a good solvent?

Because its polarity allows it to dissolve many substances.

What is the difference between hydrophilic and hydrophobic?

• Hydrophilic: interacts with water

• Hydrophobic: does not interact with water

What is the difference between organic and inorganic molecules?

• Organic: carbon-based

• Inorganic: mostly non-carbon molecules

What are monomers and polymers?

• Monomer: building block

• Polymer: chain of monomers

What is dehydration synthesis?

Joining monomers by removing water.

What is hydrolysis?

Breaking polymers into monomers by adding water.

Name the types of carbohydrates and their roles.

• Monosaccharides: energy source

• Disaccharides: transport or short-term energy

• Polysaccharides: storage (glycogen, starch) or structure (cellulose)

Name the types of lipids and their roles.

• Triglycerides: energy storage

• Phospholipids: membranes

• Steroids: hormones, membrane stability

Difference between saturated and unsaturated fats.

• Saturated: no double bonds, solid at room temp

• Unsaturated: one or more double bonds, liquid at room temp

What are essential fatty acids?

Fats that must be obtained from the diet.

Structure of an amino acid.

Central carbon, hydrogen, amino group (–NH2), carboxyl group (–COOH), and R group.

Levels of protein structure.

Primary, Secondary, Tertiary, Quaternary.

How do enzymes work?

Proteins that lower activation energy and speed up reactions.

Types of nucleic acids and their roles.

DNA: stores genetic info; RNA: helps synthesize proteins (mRNA, tRNA, rRNA).

Role of ATP.

Main energy currency of the cell.

What is the structure of the cell membrane?

Phospholipid bilayer with embedded proteins.

What are the main functions of the cell membrane?

Protects the cell, regulates what enters and exits, communication, and support.

What roles do proteins play in the cell membrane?

Channels, carriers, receptors, enzymes, and structural support.

What are tight junctions?

Connections that prevent substances from passing between cells.

What are desmosomes?

Anchoring junctions that hold cells together, providing strength.

What are gap junctions?

Channels that allow ions and small molecules to pass directly between cells.

What can cross the cell membrane easily?

Small, nonpolar molecules like oxygen and carbon dioxide.

What is a concentration gradient?

Difference in the concentration of a substance across a space or membrane.

What is diffusion?

Movement of molecules from high to low concentration.

What is facilitated diffusion?

Movement of molecules from high to low concentration with the help of membrane proteins.

What is the difference between channel and carrier proteins?

• Channel: forms pores for substances to pass through

• Carrier: changes shape to move substances across the membrane

What is osmosis?

Diffusion of water across a selectively permeable membrane.

Define hypotonic, isotonic, and hypertonic solutions.

• Hypotonic: water moves into the cell (cell swells)

• Isotonic: no net water movement

• Hypertonic: water moves out of the cell (cell shrinks)

What is active transport?

Movement of substances against their concentration gradient using ATP.

What is pinocytosis?

“Cell drinking” – uptake of fluids and small molecules via vesicles.

What is phagocytosis?

“Cell eating” – engulfing large particles or cells.

What is exocytosis?

Process by which cells release substances via vesicles merging with the membrane.

What is the role of the nucleus?

Stores DNA and controls cellular activities.

What is cytoplasm?

Fluid inside the cell containing organelles, cytoskeleton, and cytosol.

What is the role of smooth ER?

Synthesizes lipids and detoxifies harmful substances.

What is the difference between lysosomes and peroxisomes?

• Lysosomes: digest cellular waste and debris

• Peroxisomes: detoxify harmful substances, including hydrogen peroxide

What is the role of mitochondria?

Produces ATP through cellular respiration.

What are the cytoskeletal elements and their roles?

• Microfilaments: maintain cell shape

• Microtubules: support, intracellular transport

• Intermediate filaments: provide strength

What is metabolism?

All chemical reactions in the body that maintain life.

What is catabolism?

The breakdown of molecules to release energy.

What is anabolism?

The synthesis of molecules that requires energy.

What are the major components of cellular respiration?

Glycolysis, Krebs cycle (citric acid cycle), Electron Transport Chain.

What are the inputs and outputs of glycolysis?

• Input: glucose

• Output: 2 ATP, 2 NADH, 2 pyruvate

What are the inputs and outputs of the Citric Acid cycle?

• Input: 2 ATP, 2 NADH, 2 pyruvate

• Output: ATP + NADH + CO 2

What are the inputs and outputs of the Electron Transport Chain (ETC)?

• Input: NADH + O2

• Output: ~32–34 ATP, H2O

How is ATP produced with and without oxygen?

• With O2 (aerobic): Glycolysis → Krebs cycle → ETC → ~36 ATP

• Without O2 (anaerobic): Glycolysis → fermentation → 2 ATP

Compare glucose vs fats in energy production.

Glucose: quick energy, less ATP per molecule.
Fats: slower energy, more ATP per molecule.

What are the steps of interphase and their roles?

• G1: cell growth

• S: DNA replication

• G2: preparation for mitosis

What is DNA replication?

The process of copying DNA to prepare for cell division.

What enzymes are involved in DNA replication?

Helicase (unwinds DNA), DNA polymerase (builds new strand), ligase (joins fragments).

What are the major steps of mitosis?

Prophase, Metaphase, Anaphase, Telophase.

Difference between mitosis and meiosis?

• Mitosis: 1 division → 2 identical daughter cells, somatic cells

• Meiosis: 2 divisions → 4 non-identical gametes, sex cells

What is a gamete?

A sex cell (sperm or egg) with half the chromosome number.

What is a chromosome?

A condensed structure of DNA that carries genetic information.

What is a gene?

A segment of DNA that codes for a specific protein.

Difference between DNA and RNA?

• DNA: double-stranded, stores genetic info, deoxyribose, lacks oxygen, A T C G

• RNA: single-stranded, helps make proteins, ribose, has oxygen, A U C G

Difference between mRNA, rRNA, tRNA?

• mRNA: carries code from DNA

• rRNA: part of ribosome

• tRNA: brings amino acids to ribosome

What is transcription and where does it occur?

Copying DNA into mRNA; occurs in the nucleus.

What is translation and where does it occur?

Converting mRNA into a protein; occurs at ribosomes in the cytoplasm.

What is a mutation?

A change in DNA sequence.

What is totipotency?

The ability of a cell to become any other type of cell.

What are the roles of epithelial tissue?

Protection, secretion, absorption, and filtration.

Name the types of epithelial tissues, their locations, and roles.

• Simple squamous: alveoli, filtration/diffusion

• Stratified squamous: skin, protection

• Simple cuboidal: kidney tubules, secretion/absorption

• Stratified cuboidal: ducts of glands, protection

• Simple columnar: intestines, absorption/secretion

• Pseudostratified columnar: respiratory tract, secretion/movement

• Transitional: urinary bladder, stretches

What are the types of glands and their products?

• Endocrine: secrete hormones into blood

• Exocrine: secrete onto surfaces or into ducts

What is the structure of connective tissue?

ells, fibers (collagen, elastic, reticular), and ground substance.

Name the three types of connective fibers.

Collagen, Elastic, Reticular.

What is areolar tissue and its roles?

Loose connective tissue; cushions organs, supports blood vessels.

What is adipose tissue and its roles?

Stores fat for energy, insulates, cushions organs.