H Lab Biology Study Guide

Sometimes between Oct 12-15

Cell Theory

All living things are made of cells; cells are the basic unit of structure and function; all cells come from existing cells.

Robert Hooke

In 1665, observed a thin slice of cork and named the structures cells.

Anton van Leeuwenhoek

In 1673, used a simple microscope to view living organisms in pond water and tooth scrapings.

Matthias Schleiden

In 1838, concluded that all plants were made of cells.

Theodor Schwann

In 1839, concluded that all animals were made of cells.

Rudolf Virchow

In 1855, reasoned that all cells come from preexisting cells through cell division.

Endosymbiotic Theory

The theory that some organelles were once free-living cells; mitochondria and chloroplasts have their own DNA.

Unicellular

An organism made of one cell.

Multicellular

An organism made of many cells that may organize into tissues.

Differentiation

The process in which cells become specialized by turning different genes on and off.

Atom

A basic unit of an element; a nonliving level of organization.

Molecule

Atoms joined together, such as in carbohydrates and proteins.

Organelle

A small cell structure that performs a specific function.

Cell

The basic unit of life.

Tissue

Similar cells working together.

Organ

Different tissues working together.

Organ System

Different organs working together.

Organism

An individual living thing.

Population

One species living in an area.

Community

Several populations living in an area.

Ecosystem

An area containing interacting organisms and their environment.

Biome

A large region, such as tundra or tropical rainforest.

Biosphere

All living and nonliving things on Earth.

Prokaryote

A cell without a nucleus or membrane-bound organelles; includes bacteria.

Nucleoid Region

The region of a prokaryotic cell that contains DNA.

Eukaryote

A cell with a nucleus and membrane-bound organelles; includes protists, fungi, plants, and animals.

Cell Membrane

A phospholipid bilayer with proteins that surrounds all cells and controls what enters and leaves.

Phospholipid Bilayer

The two layers of phospholipids that form the cell membrane.

Hydrophilic

Attracted to water; describes phospholipid heads.

Hydrophobic

Repels water; describes phospholipid tails.

Cell Membrane Proteins

Help transport large molecules and aid in cell recognition.

Glycoproteins

Proteins with carbohydrate chains that act as markers for cell recognition.

Cell Wall

A nonliving layer outside the cell membrane that supports and protects the cell.

Plant Cell Wall Material

Cellulose.

Bacterial Cell Wall Material

Peptidoglycan.

Fungal Cell Wall Material

Chitin.

Cytoplasm

Jelly-like substance inside the cell membrane that contains organelles and provides a place for chemical reactions.

Nucleus

Controls normal cell activities and contains DNA in chromosomes.

Nuclear Envelope

The double membrane surrounding the nucleus.

Nuclear Pores

Openings in the nuclear envelope that allow materials to enter and leave the nucleus.

DNA

The hereditary material of the cell; genes in DNA code for proteins.

Gene

A section of DNA that contains instructions related to cell characteristics, often by coding for a protein.

Chromatin

DNA in a spread-out form in non-dividing cells.

Chromosome

Condensed DNA wrapped around proteins, visible during cell division.

Nucleolus

A structure inside the nucleus that makes ribosomes.

Cytoskeleton

A protein framework that helps maintain cell shape and move organelles.

Microfilaments

Threadlike cytoskeleton structures made of actin.

Microtubules

Tubelike cytoskeleton structures made of tubulin.

Centrioles

Structures in animal cells that help form the spindle during cell division and separate chromosomes.

Mitochondria

The cell's powerhouse; produce ATP through cellular respiration.

Cristae

Folds of the inner mitochondrial membrane that increase surface area for chemical reactions.

Matrix

The interior of a mitochondrion.

Endoplasmic Reticulum (ER)

A network of membrane tubules involved in making and transporting cell products.

Rough ER

Has ribosomes; makes and processes proteins, including proteins for export.

Smooth ER

Lacks ribosomes; makes lipids, regulates calcium, and helps destroy toxic substances.

Ribosomes

Protein factories that join amino acids to make proteins.

Protein Synthesis

The process of making proteins.

Golgi Apparatus

Modifies, sorts, and packages molecules from the ER for storage or transport.

Cis Face

The receiving side of the Golgi apparatus.

Trans Face

The shipping side of the Golgi apparatus.

Vesicles

Small membrane-bound sacs that transport materials from the ER to the Golgi and toward the cell membrane.

Lysosomes

Contain digestive enzymes that break down food, bacteria, and worn-out cell parts.

Cilia

Short, numerous structures that move cells or materials across a cell surface.

Flagella

Longer, fewer structures that help cells move.

Vacuoles

Fluid-filled sacs used for storage.

Central Vacuole

The large central vacuole in plant cells that stores cell sap and other substances.

Contractile Vacuole

A structure in some unicellular protists that pumps out excess water to maintain homeostasis.

Chloroplasts

Organelles in photosynthetic producers that use sunlight to make glucose.

Photosynthesis

The process of using sunlight to make food; energy is stored in the chemical bonds of sugars.

Thylakoids

Membrane sacs inside chloroplasts.

Grana

Stacks of thylakoids inside chloroplasts.

Stroma

Gel-like material surrounding thylakoids in chloroplasts.

Characteristics of Living Things

Cells, energy use, reproduction, homeostasis, organization, response to the environment, growth and development, and exchange of materials.

Surface Area

For a rectangular cell model, length multiplied by width.

Volume

For a rectangular cell model, length multiplied by width multiplied by height.

Why Cell Size Is Limited

Volume increases faster than surface area, making it harder to exchange enough materials and remove wastes as a cell grows.

Elephant Cells vs. Mouse Cells

Their cells are about the same size; an elephant has many more cells.