BIO 181 Exam 1 review

Hypothesis

A testable guess that explains how or why something happens

Hypothesis vs Prediction

A hypothesis is the explanation; a prediction is what you expect to see happen ("If… then…")

Testable Hypothesis

An idea you can actually prove wrong or right with an experiment

Theory (Scientific vs Everyday)

In daily life, a theory is just a guess; in science, it is a well-tested explanation backed by tons of evidence

Independent Variable

The one thing YOU change or test in an experiment

Dependent Variable

The thing you measure to see the results

Controlled Variables (Constants)

Things you keep exactly the same so the test is fair

Inductive Reasoning

Looking at specific clues or data to come up with a general rule

Deductive Reasoning

Starting with a general rule to predict what will happen in a specific case

Positive Control

A test group you already know WILL work (proves your test works)

Negative Control

A test group you know will NOT react (gives you a baseline to compare to)

Why Controls Matter

They prove your results came from your test, not an accident

Sample Size

How many sample things you test; bigger groups give more trustworthy results

8 Properties of Life

Order, reacting to stimuli, reproduction, adapting, growing, keeping balance (homeostasis), using energy, and metabolism

Parts of an Atom

Protons and neutrons sit in the center nucleus; electrons buzz around the outside

Particle Charges

Proton = positive (+), Electron = negative (-), Neutron = neutral (0)

What Identifies an Element?

The number of protons (atomic number); this number never changes

Isotope

Atoms of the same element with different numbers of neutrons (different weights)

Ion

An atom that gained or lost electrons

Chemical Bond

The glue that holds atoms together using electrons

Ionic vs Covalent Bonds

Ionic steals/transfers electrons (metal + nonmetal); Covalent shares electrons (nonmetals)

Electronegativity

How greedy an atom is for electrons; unequal sharing makes polar bonds, equal sharing makes nonpolar bonds

Hydrogen Bond

A weak stickiness between the positive hydrogen of one molecule and the negative side of another

Atoms That Make Hydrogen Bonds

Hydrogen paired with Fluorine, Oxygen, or Nitrogen (FON)

5 Cool Properties of Water

Sticky to itself/others, resists heating up, cools you when it evaporates, ice floats, dissolves almost anything

Phospholipid Bilayer

Heads love water and face out; tails hate water and hide on the inside

Hydrophobic Effect

Water pushes nonpolar fats together, forcing cell membranes to form automatically

What pH Actually Measures

How many free hydrogen ions (H+) are floating in a liquid

Acids

pH below 7; full of H+ ions (sour, proton donors)

Bases

pH above 7; low in H+ ions (slippery, proton acceptors)

Dehydration Synthesis

Snapping small pieces together by removing a water molecule

Hydrolysis

Breaking large pieces apart by adding water ("hydro" = water, "lysis" = break)

4 Functional Groups

Hydroxyl (-OH), Carboxylic Acid (-COOH), Amino (-NH2), and Phosphate (-PO4)

Carb Monomer & Role

Monomer: Monosaccharide (like glucose); gives fast energy and plant structure (cellulose)

Lipid Building Blocks and Role

Glycerol and fatty acids; store long-term energy, cushion organs, make cell membranes

Saturated vs Unsaturated Fat

Saturated has no double bonds and is solid (butter); Unsaturated has bends/double bonds and is liquid (oil)

Protein Monomer & Role

Monomers: 20 amino acids; they do the cell's physical work, build muscles, and act as enzymes

4 Levels of Protein Structure

Primary (chain), Secondary (spirals/sheets), Tertiary (3D ball), Quaternary (team of balls)

Nucleic Acid Monomer & Role

Monomer: Nucleotide; stores genetic instructions (DNA/RNA) to build proteins

DNA vs RNA

DNA is double-stranded with Thymine (T); RNA is single-stranded with Uracil (U)

Purines vs Pyrimidines

Purines (A, G) are big with 2 rings; Pyrimidines (C, T, U) are small with 1 ring

Cell Theory (4 Rules)

All living things have cells, cells are the basic unit of life, whole bodies depend on cells, cells only come from other cells

4 Things ALL Cells Share

Cell membrane, cytoplasm (goo), DNA (instructions), and ribosomes (protein builders)

Prokaryote vs Eukaryote

Prokaryotes are tiny bacteria with no nucleus; Eukaryotes are complex cells with a true nucleus and organelles

Cell Wall

Tough outer box that gives plant/bacteria cells rigid structure

Nucleus

The control room that protects DNA (eukaryotes only)

Ribosomes

Tiny factories that build proteins

Rough ER

Ribosome-covered tunnels that fold and send off new proteins

Smooth ER

Clean tunnels that make lipids and break down drugs/toxins

Golgi Apparatus

The post office that inspects, packs, and ships proteins

Mitochondria

The power plants of the cell; turn food and oxygen into ATP energy

Chloroplast

Solar panels in plant cells that make sugar from sunlight (photosynthesis)

Lysosome

Trash compactor with acid that digests old parts and invaders

Vacuole

Storage tank; large central vacuole holds water in plants, contractile vacuole pumps water out of protists

Endosymbiotic Theory

Mitochondria and chloroplasts used to be free bacteria that moved inside bigger cells long ago

Proof for Endosymbiosis

Mitochondria and chloroplasts have their own circular DNA, double membranes, and divide like bacteria

3 Membrane Ingredients

Phospholipids (the wall), proteins (doors/anchors), and carbs (ID tags) ingredients

Passive Transport

Molecules moving from high to low concentration for free (no energy needed)

Simple vs Facilitated Diffusion

Simple slips right through lipids; Facilitated needs a protein tunnel/doorway to get through

Osmosis

The diffusion of water across a membrane to balance out salt/sugar levels

Hypertonic Solution

Extra salty/sugary outside; solution sucks water OUT of the cell, making it shrivel up

Hypotonic Solution

Watery solution outside; rushes INTO the cell, making it swell and pop

Isotonic Solution

Equal balance of water and solute; cell stays completely normal

Active Transport

Using energy (ATP) to transport molecules from low to high concentration (pumping uphill)

Endocytosis vs Exocytosis

Endocytosis swallows things into the cell; Exocytosis spits things out of the cell

Phagocytosis vs Pinocytosis

Phagocytosis is "cell eating" large solids; Pinocytosis is "cell drinking" fluids