BIOL 1011K Mid-Term Exam Study Guide

Levels of Organization

Cell → Tissue → Organ → Organ System → Organism → Population → Community → Ecosystem → Biosphere

Cell

The basic unit of structure and function in living things.

Tissue

A group of cells with similar structure and function.

Organ

Composed of multiple tissues performing a specific function.

Organ System

Multiple organs working together to perform complex functions.

Population

All individuals of a species living in a given area.

Community

All populations in a defined area, consisting only of living things.

Ecosystem

All living organisms plus abiotic factors in a given area.

Biosphere

The global sum of all ecosystems; the zone of life on Earth.

Prokaryotes

Unicellular organisms without a nucleus, no organelles, DNA is located in cytoplasm (nucleoid), ex. bacteria and archaea.

Eukaryotes

Organisms with cells that have a nucleus (where DNA is located), organelles, ex. Plants, Animals, Fungi, Protists

Hypothesis

A testable and falsifiable proposed explanation.

Theory

A broad explanation supported by a large body of evidence.

Chemical Bonds

Interactions that hold atoms together; includes covalent, ionic, and hydrogen bonds.

Covalent Bonds

Bonds formed by the sharing of electrons between atoms.

Ionic Bonds

Bonds formed by the transfer of electrons, creating charged ions.

Hydrogen Bonds

Weak attractions between partially charged atoms; important in water and DNA. They stabilize the 3D shape of DNA (base pairing) and protein folding (secondary/tertiary structure).

pH Scale

Measures the acidity or alkalinity of a solution.

Buffers

Substances that stabilize pH by absorbing or releasing hydrogen ions.

Macromolecules

Large complex molecules essential for life, including carbohydrates, proteins, lipids, and nucleic acids.

Carbohydrates

Organic compounds used for energy storage and structure. - Monomer: monosaccharide

Key bond: glycosidic bond

ex. glucose, starch

Proteins

Macromolecules made of amino acids that perform a variety of functions.

Monomer: Amino acid (they differ by their R-group)

Key bond: peptide bond

ex. hemoglobin, enzymes

Lipids

Fats and oils that are used for membranes and energy storage.

No true monomer

Key bond: Ester

ex. phospholipids, triglycerides

Nucleic Acids

Biomacromolecules that store and transmit genetic information.

Monomer: Nucleotide

Key bond: Phosphodiester bond

ex. DNA, RNA

Cell Theory

The theory that all living things are composed of cells, which are the basic units of life. Cells arise from pre-existing cells.

Light Microscope

A microscope that uses visible light to view live cells.

Electron Microscope

A microscope that uses electrons to achieve high magnification of dead samples.

Active Site

The region of an enzyme where substrate molecules bind.

Exergonic

Reactions that release energy (spontaneous).

Endergonic

Reactions that require energy input (non-spontaneous).

Anabolic Pathways

Metabolic pathways that build complex molecules from simpler ones, consuming energy.

Catabolic Pathways

Metabolic pathways that break down complex molecules into simpler ones, releasing energy.

Cellular Respiration

The process by which cells convert glucose into usable energy (ATP).

Fermentation (no oxygen)

• Glycolysis ➡ Pyruvate.

• Pyruvate is converted to:

  • Alcohol + CO2 (yeast).

  • Lactic Acid (animals).

Characteristics of Living Things

• Order/Organization

• Reproduction

• Growth & Development

• Energy Processing (Metabolism)

• Homeostasis (Maintaining Internal Stability)

• Response to Environment

• Evolutionary Adaptation

Experimental Design

Uses a control group (baseline for comparison) and experimental group (contains variable being tested).

Bacteria

Unicellular prokaryotes with peptidoglycan cell walls.

Archaea

Unicellular prokaryotes living in extreme environments.

Eukarya

All eukaryotic organisms (plants, animals, fungi, protists).

Proton

 (positive, nucleus)

Neutron

(neutral, nucleus)

Electron

(negative, orbitals)

isotopes

Same element, different neutron count (affects atomic mass)

Atomic Mass

Number of protons + neutrons

Polar covalent bonds

Bonds formed between atoms with different electronegativities, resulting in unequal sharing of electrons. (within the water molecule)

hydrogen bonds

Weak attractions between polar molecules, such as water, due to the partial positive charge of hydrogen and the partial negative charge of oxygen. (between water molecules)

cohesion

The attraction between molecules of the same substance, which in water leads to surface tension and the ability to form droplets.

adhesion

The attraction between molecules of different substances, which allows water to stick to surfaces like glass and plant tissues. (capillary action)

pH scale

• Acid (pH < 7) – More H+ ions.

• Base (pH > 7) – Fewer H+ ions.

7 is neutral

buffers

• Stabilize pH by absorbing or releasing H+ ions (critical in blood).

Phospholipids

Form membranes/a bilayer (hydrophilic head, hydrophobic tails).

• Hydrophilic heads face water.

• Hydrophobic tails hide from water.

• Self-assemble in water (due to amphipathic nature).

Nucleotide components

Sugar + Phosphate + Nitrogenous Base

Prokaryotes

Have no organelles. Are smaller than eukaryotes. Have circular DNA.

Eukaryotes

Have organelles. Are larger than prokaryotes. Have linear DNA (located in nucleus).

Animal Cells

Have no chloroplasts. Have no cell wall. And do not have a central vacuole.

Plant cells

Have a chloroplast. Have a cell wall (cellulose). Have a central vacuole.

Nucleus

stores DNA

Mitochondria

ATP production (cellular respiration).

Chloroplast

Photosynthesis (plants).

Golgi apparatus

Packages and modifies proteins.

Endoplasmic Reticulum

• Rough ER – Protein synthesis.

• Smooth ER – Lipid synthesis.

Peroxisome

Breaks down fatty acids and toxins (like hydrogen peroxide).

Competitive Inhibitor

blocks active site

non-competitive inhibitor

Binds elsewhere (allosteric site), changes enzyme shape.

Glycolysis (cytoplasm)

Glucose ➡ 2 Pyruvate + 2 ATP + 2 NADH.

Citric Acid Cycle (mitochondrial matrix)

Pyruvate ➡ CO2 + NADH + FADH2 + 2 ATP.

Electron Transport Chain (inner mitochondrial membrane)

• Use NADH & FADH2 to pump H+ across membranes.

• Oxygen = final electron acceptor.

• H+ gradient powers ATP Synthase ➡ 32-34 ATP.

Obligate Anaerobes

Die in oxygen (oxygen is toxic).