ss biology semester 2 final

Controlled Variable

A factor that stays the same throughout an experiment.

Control Group

The group that does not receive the independent variable and is used for comparison.

Experimental Group

The group that receives the independent variable being tested.

Control Group vs. Experimental Group

The control group does not receive the treatment; the experimental group does.

Controlled Variable vs. Control Group

A controlled variable is something kept constant, while a control group is the comparison group.

Hypothesis

A testable prediction or explanation based on observations.

Theory

A well-tested explanation supported by a large amount of evidence.

Hypothesis vs. Theory

A hypothesis is tested; a theory has already been tested many times and is strongly supported by evidence.

Cell Theory

(1) All living things are made of cells. (2) The cell is the basic unit of life. (3) All cells come from pre-existing cells.

Organelle

A specialized structure inside a cell that performs a specific function.

Nucleus

Stores most of the genetic material (DNA) in eukaryotic cells.

Ribosomes

Make proteins.

Rough Endoplasmic Reticulum (RER)

Has ribosomes attached; modifies and transports proteins.

Smooth Endoplasmic Reticulum (SER)

Makes lipids and detoxifies harmful substances.

Golgi Apparatus

Modifies, sorts, packages, and ships proteins.

Mitochondria

Produce ATP through cellular respiration.

Chloroplast

Site of photosynthesis in plant cells.

Lysosome

Breaks down waste and old cell parts.

Vacuole

Stores water, food, and wastes.

Central Vacuole

Large storage organelle in plant cells that helps maintain turgor pressure.

Cell Membrane

Controls what enters and leaves the cell.

Cell Wall

Provides support and protection; found in plants, fungi, and bacteria.

Cytoplasm

Jelly-like fluid where organelles are found.

Cytoskeleton

Gives the cell shape and helps movement.

Phospholipid Bilayer

Double layer that makes up the cell membrane.

Phospholipid Heads

Hydrophilic (water-attracting); face toward water.

Phospholipid Tails

Hydrophobic (water-repelling); face inward away from water.

Why are phospholipids arranged this way?

Heads interact with water inside and outside the cell while tails avoid water.

Secreted Protein Pathway

Ribosome

Prokaryote

Small, simple cell without a nucleus or membrane-bound organelles.

Eukaryote

Larger, more complex cell with a nucleus and membrane-bound organelles.

Endosymbiotic Theory

Mitochondria and chloroplasts were once free-living bacteria that were engulfed by larger cells.

Mitochondria vs. Chloroplasts

Both have double membranes and their own DNA. Mitochondria make ATP; chloroplasts perform photosynthesis.

Unit 9: Working Cell

Metabolism

All chemical reactions occurring in a cell.

Potential Energy

Stored energy.

Kinetic Energy

Energy of motion.

Endothermic Reaction

Absorbs energy; not spontaneous.

Exothermic Reaction

Releases energy; usually spontaneous.

Catalyst

Speeds up chemical reactions without being used up.

Enzyme

A protein catalyst.

Active Site

Region of an enzyme where the substrate binds.

First Law of Thermodynamics

Energy cannot be created or destroyed.

Second Law of Thermodynamics

Every energy transfer increases entropy (disorder).

Gradient

Difference in concentration that stores potential energy.

ATP

Cell's main energy molecule.

NADPH

High-energy electron carrier used in photosynthesis.

Simple Diffusion

Movement from high to low concentration without proteins.

Facilitated Diffusion

Movement from high to low concentration using transport proteins.

Osmosis

Diffusion of water across a selectively permeable membrane.

Hypotonic Solution

Lower solute concentration outside the cell; water enters the cell.

Hypertonic Solution

Higher solute concentration outside the cell; water leaves the cell.

Isotonic Solution

Equal solute concentrations; no net movement of water.

Red Blood Cell in Hypotonic Solution

Swells and may burst.

Red Blood Cell in Hypertonic Solution

Shrivels.

Red Blood Cell in Isotonic Solution

Stays normal.

Plant Cell in Hypotonic Solution

Becomes firm (turgid).

Plant Cell in Hypertonic Solution

Plasmolyzes (membrane pulls away from cell wall).

Plant Cell in Isotonic Solution

Becomes limp.

Active Transport

Uses energy (ATP) to move molecules against the concentration gradient.

Unit 10: Cellular Respiration and Photosynthesis

Cellular Respiration Equation

Glucose + Oxygen

Order of Cellular Respiration

Glycolysis

Where does pyruvic acid go after glycolysis?

Into the mitochondria where it becomes Acetyl-CoA.

Glycolysis Location

Cytoplasm.

Glycolysis Inputs

Glucose, ATP, NAD+.

Glycolysis Outputs

Pyruvate, ATP, NADH.

Krebs Cycle Location

Mitochondrial Matrix.

Electron Transport Chain Location (Respiration)

Inner mitochondrial membrane.

Aerobic

Requires oxygen.

Anaerobic

Does not require oxygen.

Fermentation

Produces ATP without oxygen by regenerating NAD+.

NAD+

Oxidized electron carrier.

NADH

Reduced electron carrier carrying high-energy electrons.

Photosynthesis Equation

Carbon Dioxide + Water + Light

Light-Dependent Reactions Location

Thylakoid membranes.

Light-Dependent Inputs

Water, sunlight, ADP, NADP+.

Light-Dependent Outputs

Oxygen, ATP, NADPH.

Where does oxygen come from in photosynthesis?

Splitting of water molecules.

Calvin Cycle Location

Stroma.

Calvin Cycle Inputs

Carbon dioxide, ATP, NADPH.

Calvin Cycle Outputs

Glucose (G3P), ADP, NADP+.

NADPH

Carries high-energy electrons for the Calvin Cycle.

Chlorophyll

Green pigment that absorbs light energy.

Where is chlorophyll located?

Thylakoid membranes of chloroplasts.

Green Leaves Appear Green Because…

Green light is reflected, not absorbed.

ATP Synthase

Enzyme that produces ATP using a proton gradient.

Electron Transport Chain (Photosynthesis)

Uses energized electrons to create ATP and NADPH.

Natural Selection

Individuals with beneficial traits survive and reproduce more.

Adaptation

Inherited trait that improves survival.

Fitness

Ability to survive and reproduce successfully.

Homologous Structures

Similar structures from a common ancestor.

Analogous Structures

Similar function but different evolutionary origin.

Transitional Fossil

Fossil showing traits between ancestral and modern organisms.

Taxonomy

Science of classifying organisms.

Taxonomic Levels

Domain

Evidence for Evolution

Fossils, embryology, homologous structures, DNA similarities, molecular biology.

Geologic Evidence

Earth is much older than originally believed, allowing time for evolution.

Molecular Homologies

Similar DNA indicates closer evolutionary relationships.

Virus

Nonliving particle that reproduces only inside a host cell.