biology q1

Cell

The basic unit of structure and function in living things.

Robert Hooke (1665)

Discovered cells.

Anton van Leeuwenhoek (1674)

Observed simple organisms like bacteria.

Robert Brown

Discovered the nucleus.

Felix Dujardin

Discovered fluid content of the cell.

Matthias Schleiden

Proposed that all plants are made of cells.

J.E. Purkinje

Named the fluid content of the cell as protoplasm.

Theodor Schwann

Proposed that all animals are made of cells.

Carl Heinrich Braun (1845)

Proposed that the cell is the basic unit of life.

Rudolf Virchow

Proposed that new cells are formed only from cells that already exist.

Unicellular Organism

An organism made up of one cell.

Multicellular Organisms

Organisms composed of multiple cells.

Nucleus

Control center of the cell.

DNA

A complex molecule containing the genetic information that makes up the chromosomes.

Endoplasmic Reticulum (ER)

The transportation system of the cell; it moves materials around the cell.

Lysosome

A small, round cell structure containing chemicals that break down large food particles into smaller ones.

Cytoplasm

A jellylike fluid inside the cell in which the organelles are suspended.

Cell Membrane

A cell structure that controls which substances can enter or leave the cell.

Mitochondrion

Cell organelle that converts chemical energy stored in food into compounds more convenient for the cell to use.

Golgi Complex

Organelle that packages and distributes proteins.

Ribosome

Makes proteins.

Vacuole

A sac inside a cell that acts as a storage area.

Centriole

Structure in an animal cell that helps organize cell division.

Cytoskeleton

A network of fibers that holds the cell together, helps maintain its shape, and aids in movement.

Prokaryote

A unicellular organism that lacks a nucleus and membrane-bound organelles.

Eukaryote

A cell that contains a nucleus and membrane-bound organelles.

Passive Transport

The movement of substances across a cell membrane without the use of energy by the cell.

Active Transport

Energy-requiring process that moves material across a cell membrane against a concentration difference.

Biological Molecules

All molecules produced by living things.

Inorganic Compounds

Compounds that do not contain carbon or contain carbon bound to elements other than hydrogen.

Organic Compounds

Compounds that contain carbon.

Macromolecule

Large molecule formed by joining smaller organic molecules together.

Polymer

A long molecule consisting of many similar or identical monomers linked together.

Monomer

A simple compound whose molecules can join together to form polymers.

Interphase

Cell grows, performs normal functions, and prepares for division; consists of G1, S, and G2 phases.

First Gap Phase (G1 Phase)

Part of interphase where a cell undergoes normal activity, such as making necessary chemicals and growing.

Synthesis Phase (S Phase)

Part of interphase where DNA is replicated.

Second Gap Phase (G2 Phase)

Growth and preparation for mitosis, including DNA proofreading.

M Phase

The phase of the cell cycle that includes mitosis and cytokinesis.

G0 Phase

A nondividing state occupied by cells that have left the cell cycle, sometimes reversibly.

Mitosis

Also called karyokinesis; the period of the cell cycle during which duplicated chromosomes are separated into identical nuclei; includes prophase, prometaphase, metaphase, anaphase, and telophase.

Prophase

Chromosomes become visible, nuclear envelope dissolves, and spindle forms.

Metaphase

Chromosomes line up in the middle of the cell.

Anaphase

Chromosomes separate and move to opposite ends of the cell.

Telophase

After chromosomes separate, the cell seals off; final phase of mitosis.

Cytokinesis

Division of the cytoplasm to form two separate daughter cells.

Transport Mechanism

Permeability of substances across the cell membrane depends on their solubility in lipids and not molecular size.

Simple Diffusion

Movement from higher to lower concentration.

Facilitated Diffusion

A carrier-mediated process of moving substances.

Osmosis

The process of moving water through a semi-permeable membrane toward an ion- or solute-rich region in a solution.

Ion Channels

Specialized protein molecules that span the membrane.

Active Transport

Requires specialized integral proteins called transporters.

Vesicular Transport

Transport of membrane-bounded substances across the plasma membrane.

Uniport

Movement of a single substance.

Symport System

Transport of two substances using energy produced by concentration differences from primary active transport.

Antiport System

Two substances move across the membrane in opposite directions.

Element

Simplest form of a substance.

Water

A versatile solvent.

Acids

Substances that increase hydrogen ion concentration in a solution.

Base

Substances that decrease hydrogen ion concentration in a solution.

Electrolytes or Salts

Produced when an acid is combined with a base.

Carbon Dioxide

Essential for plants to perform photosynthesis.

Leptotene, Zygotene, Pachytene, Diplotene, Diakinesis

The five events taking place in Prophase I.