TEAS Science Review Basics

Independent Variable

The variable that is measured or observed

Dependent Variable

The variable that is measured or observed

Control Group

The group that does not receive the treatment and is used for comparison

Experimental Group

The group receiving the treatment being tested

Constants

Factors kept the same for every group

Random Sampling

Choosing participants randomly to reduce bias

Bias

Anything that unfairly influences the results

Placebo

A fake treatment used to compare against the real treatment

What makes a good experiment?

one independent variable, one dependent variable, large sample size, random selection, control group, repeated trials

What should I do if I don’t know the answer?

Eliminate the wrong answers, look for scientific vocabulary, choose the most complete answer, avoid absolute words like ALWAYS or NEVER unless clearly true

Gram (g)

Measure mass : paperclip = 1 gram

Kilogram (kg)

Measures large masses : 1kg = 1000g

Meter (m)

measures length

Millimeter (mm)

very small length

Centimeter (cm)

small length : 100cm = 1m

Liter (L)

measures liquid volume

Millimeter (mL)

small liquid volume: 1000mL = 1L

Celsius (C)

measures temperature

Levels of Organization (smallest < largest)

Atom = Molecule = Macromolecule = Organelle = Cell = Tissue = Organ = Organ System = Organism

Carbohydrates

Function: quick energy

Monomer: Monosaccharide

Polymer: Polysaccharide

Examples: Glucose, Starch, Glycogen

Proteins

Function: Structure, Enzymes, Transport

Monomer: Amino Acid

Examples: Hemoglobin, Enzymes, Keratin

Lipids

Function: Long-term energy, Cell membranes, Hormones

Building Blocks: Glycerol + fatty acids

Examples: Fats, Oils, Cholesterol

Nucleic Acids

Function: Store genetic information

Monomer: Nucleotide

Examples: DNA and RNA

Nucleus

Stores DNA

Ribosome

Makes proteins

Rough ER

Modifies proteins

Smooth ER

Makes lipids and detoxifies

Golgi apparatus

Packages and ships proteins

Mitochondria

Produces ATP (energy)

Lysosome

Digests waste

Vacuole

Stores water and nutrients

Chloroplasts

Photosynthesis (Plants only)

Cell Wall

Support and protection (Plants only)

Transcription

DNA —> mRNA , Occurs in the nucleus

Translation

mRNA —-> Protein, occurs at ribosomes

Codon

Three mRNA bases coding for one amino acid

Anticodon

Three tRNA bases matching a codon

Silent Mutation

No amino acid changes

Missense Mutation

One amino acid changes

Nonsense Mutation

Creates a stop codon, protein is shortened

Frameshift Mutation

Insertions/deletions shift the reading frame, usually the most harmful

B Cells

Produce antibodies

T Helper Cells

Activate other immune cells

Cytotoxic T Cells

Kill infected cells

Macrophages

Eat pathogens, Present antigens

Neutrophils

First responders, eat bacteria

Transmissible Disease

Can spread between people: Examples = Influenza, COVID, Tuberculosis

Nontransmissible Disease

Cannot spread: Examples = Diabetes, Cancer, Hypertension

Virus

Treated with antivirals (not antibiotics): Examples = Acyclovir, Oseltamivir, Remdesivir

Bacteria

Usually treated with antibiotics: Examples = Amoxicillin, Azithromycin, Ciprofloxacin

Fungus

Treated with antifungal medications

Protozoa

Treated with antiparasitic medications

Plasma

Liquid portion carrying nutrients and hormones

Red Blood Cells

Carry oxygen using hemoglobin

White Blood Cells

Fight infection

Platelets

Help blood clot

Blood Flow Path

Body = Vena Cava = Right Atrium = Right Ventricle = Pulmonary Arteries = Lungs = Pulmonary Veins = Left Atrium = Left Ventricle = Aorta = Body

Main Job of Kidneys

filter blood, remove wastes, balance water, balance electrolytes, regulate blood pressure

Nephron

functional unit of the kidney

glomerulus

filters blood

Loop of Henle

concentrates urine

Diffusion

High—> Low concentration, No energy

Osmosis

Water moves across a membrane toward higher solute concentration: No energy

Active Transport

Low —→High concentration, Requires ATP

Passive Transport

High —> Low Concentration, No ATP

Amylase

Breaks down carbohydrates

Pepsin

Breaks down proteins

Lipase

Breaks down fats

Depolarization

Voltage-gated Na+ channels open; Na+ enters, making the inside of the neuron more positive

Repolarization

Voltage-gated K+ channels open; K+ leaves the cell, returning the membrane toward its resting potential

Resting Potential

About -70 mV, maintained by the sodium-potassium pump

Actin

Thin filament

Myosin

Thick filament, forms cross-brides with actin

Calcium (Ca2+)

Binds troponin, moving tropomyosin so myosin can bind actin

ATP

Releases myosin from actin and powers muscle contraction

FSH

Stimulates follicle development in the ovary

LH

Triggers ovulations

Estrogen

Thickens the uterine lining

Progesterone

Maintains the uterine lining for pregnancy

hCG

Maintains the corpus luteum during early pregnancy

Polar Molecules

Have unequal charges distribution: examples = water, ammonia dissolve other polar substances

Nonpolar Molecules

No charge end s: Examples = Oil, Fat, Wax dissolve other nonpolar substances

Rule for Dissolving

Like dissolves Like = polar dissolves polar = nonpolar dissolves nonpolar

Acid

High H+ Concentration , pH below 7

Base

High OH- concentration pH above 7

Neutral

pH = 7

Every 1 pH unit represents what change?

A tenfold (10*) change in H+ concentration

Blood Buffer

The bicarbonate buffer system helps maintain blood pH around 7.35-7.45

Catalyst

Speeds up a chemical reaction without being consumed

Enzyme

A biological catalyst that lowers activation energy

Le Charlier’s Principle

If a system at equilibrium is disturbed (by changing concentration, temperature, or pressure), it shifts in the direction that opposes the change to restore equlibrium

Brain

Controls and coordinates the body, processes sensory information, regulates thoughts, memory, and emotions, maintain homeostasis through the hypothalamus

Heart

Pumps blood throughout the body, sends deoxygenated blood to the lungs, sends oxygenated blood to the body, maintains blood pressure

Lungs

Exchange oxygen and carbon dioxide, help regulate blood pH by removing CO2, Oxygenate blood, remove carbon dioxide waste

Liver

Produces bile for fat digestion, detoxifies drugs and toxins, stores glycogen, vitamins, and iron, processes nutrients and makes blood proteins

Gallbladder

Stores bile made by the liver, concentrate bile, releases bile into the small intestine to digest fats

Stomach

Stores food, begins protein digestion with pepsin, mixes food with hydrochloric acid, form chyme before food enters the small intestine

Small Intestine

Completes most chemical digestion, absorbs most nutrients, receives bile from the gallbladder, receives digestive enzymes from the pancreas

Large intestine (colon)

absorbs water and electrolytes, forms and stores feces, houses bacteria that produce vitamins (such as vitamin K)

Pancreas

Produces digestive enzymes for carbohydrates, proteins, and fats, regulates blood glucose levels, secretes the hormone insulin to lower blood sugar, secretes the hormone glucagon to raise blood sugar