Biology Exam 2 Review: Organic Compounds, Atomic Structure, Water, Environment, Macromolecules

Organic compounds

Contain carbon + hydrogen; examples: carbohydrates, lipids, proteins, nucleic acids.

Inorganic compounds

Usually lack carbon; examples: water, salts, acids, bases.

Top six elements in living cells

CHNOPS → Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus, Sulfur

Trace Minerals

Needed in small amounts; examples: Iron (hemoglobin), Iodine (thyroid hormones), Zinc (enzyme function), Selenium (antioxidant).

Electrolytes

Minerals that dissociate into ions in water; examples: Na⁺, K⁺, Ca²⁺, Cl⁻. Functions: nerve impulses, muscle contraction, fluid balance.

Thyroid gland

Produces thyroid hormones (T3/T4) → regulates metabolism.

Goiter

Enlargement of thyroid.

Hyperthyroidism

Overactive thyroid → weight loss, nervousness.

Hypothyroidism

Underactive thyroid → fatigue, weight gain.

Hashimoto's Disease

Autoimmune → hypothyroidism.

Graves' Disease

Autoimmune → hyperthyroidism + eye issues.

Element

Basic unit of matter, defined by the number of protons.

Atom

Smallest unit of an element, consisting of protons, neutrons, and electrons.

Molecule

2+ atoms bonded.

Compound

Molecule with ≥2 elements.

Mixture

Physical combination, can separate.

Solvent

Dissolving agent.

Solute

Being dissolved.

Solution

Uniform mixture.

Covalent bond

Bond formed by sharing electrons.

Ionic bond

Bond formed by donating/accepting electrons.

Hydrogen bonds

Weak attraction between polar molecules.

Cation

Positive ion.

Anion

Negative ion.

Isotopes

Same element, different neutrons. or more neutrons

Radioactive isotopes

Decay → energy.

Acid

Releases H⁺ (pH < 7).

Base

Accepts H⁺ (pH > 7).

Buffers

Resist pH changes; example: antacids.

Polypeptide

a protein made of multiple amino acids that is held together by peptide bonds.

DNA -> DNA

Starts in nucleus, is called replication

DNA -> RNA

starts in nucleus, then in the cytoplasm. Is called transcription

RNA -> Protein

In the ribosome, is called translation

mRNA

messenger RNA; type of RNA that carries instructions from DNA in the nucleus to the ribosome

rRNA

ribosomal RNA; type of RNA that makes up part of the ribosome

tRNA

transfer RNA; type of RNA that carries amino acids to the ribosome

DNA TRANSLATION

A=T

G=C

RNA TRANSLATION

A=U

G=C

DNA polymerase

Checks the code, proofreads for mistakes

Gene

coding segment of DNA

ATP

energy molecule of the cell

saturated fats

single bonds with more H

unsaturated fats

double bonds with less H

electron shell

First shell 2 e-, rest of shells 8 e-

polar molecule

opposite charges

surface tension

the tension of the surface film of a liquid caused by the attraction of the particles in the surface layer by the bulk of the liquid, which tends to minimize surface area.

radioactive usage

Dating of fossils, medical treatments or medical diagnosis

fast twitch muscles

involved in fine and rapid muscle action

slow twitch muscles

Are good for endurance activities like long distance running or cycling

Bonus- What are some trace minerals and what are they good for

Mg- Good for muscles

Tissue good for storing fat

Cellulite