Science Midterm Review

Organism

Is an individual living thing made up of one or many cells, that is capable of growing and reproducing

Cell

Is the basic unit of structure and function in an organism

Unicellular

Organisms consisting of only a single cell

Multicellular

Organism containing hundreds, or even thousands of cells

Stimulus

A change in an organism's surrounding that causes the organism to react.

Response

An action or change in behavior

Homeostasis

regulation of an organism's internal environment to maintain conditions suitable for life

Reproduction

the production of offspring by a sexual or asexual process.

Sexual Reproduction

Two cells (sperm and egg) unite to produce the first cell of the new organism

Asexual Reproduction

When an organism just divide themselves in two. Identical

Heterotroph

Organisms that get energy from the food they eat.

Autotroph

Organisms that use energy from the sun to make their own food.

energy

What is released during cell respiration.

Growth

Process of becoming larger.

Development

Process of changes that occur during on organism's life.

Photosynthesis

A process that autotrophs go through to get their energy.

Metabolism

the sum of all processes that occur within a living organism in order to maintain life.

Change through time

living things evolve in order to survive

feedback mechanism

Regulation system in a living body that works to return the body to its normal internal state, or commonly known as homeostasis

DNA

molecule present in all living organisms. It is the carrier of genetic information.

Mitochondria

Powerhouse of the cell, organelle that is the site of ATP (energy) production

Robert Hooke

He gave us the word "cell" for use with living things. He discovered cells looking at cork.

Anton von Leeuwenhoek

He saw the first living microorganisms.

Matthias Schleiden

He studied plants. He looked at lots of plants under the microscope; their leaves, flowers, roots and stems. He decided that "All plants are made of cells".

Theodor Schwann

He studied animals. He looked at animal tissues under the microscope and saw cells. He came to the conclusion, "All animals are made of cells".

Rudolph Virchow

He was a doctor. He studied human illness and looked at diseased body tissue. He observed living cells dividing into two parts. He came to the conclusion that living cells reproduced and made new living cells.

Microscope

A tool used by biologists to study microscopic (TINY) details of living things.

All living things are made of cells.

The first part of The Cell Theory based on the work of Matthias Schleiden and Theodor Schwann.

Cells only come from living cells.

The third statement of The Cell Theory. This is based on Rudolf Virchow's observation of living cells reproducing.

cell theory

*All living things are composed of cells

*Cells are the basic units of structure and function in living things

*New cells are produced from existing cells

cell

The basic unit of life

cell membrane

The thin flexible barrier that surrounds a cell

nucleus

The large membrane-enclosed structure that contains genetic information in the form ofterm-30 DNA and controls many of the cell's acitivities

Organelle

A tiny cell structure that carries out a specific function within the cell

eukaryotes

Cells that enclose their DNA in nuclei; animal and plant cells

prokaryotes

Cells that do not enclose their DNA in nuclei; bacteria

cell wall

A rigid structure that surrounds the cell membrane and provides support to the plant cell

Chloroplast

An organelle found in plant and algae cells where photosynthesis occurs

cells make

tissues

Unicellular

Made of a single cell

Multicellular

Consisting of many cells

Exception to the Cell Theory

Viruses reproduce but are not but are not made up of cells

Endosymbiotic Theory

a theory that states that certain kinds of prokaryotes began living inside of larger cells and evolved into the organelles of modern-day eukaryotes

polymer

A large molecule composed of repeating smaller units or monomers.

carbohydrate

Compound containing carbon, hydrogen, and oxygen (CHO), provides quick energy and is a part of the structure of cell wall

protein

Class of nutrients made up of amino acids.

lipid

Organic molecules made of carbon, hydrogen and oxygen. Used for long term energy (CHO)

nucleic acid

A biological molecule (DNA or RNA) composed of the elements C, H, N, O, and P that carries genetic information (CHONP)

amino acid

Monomer of protein

monosaccharide

monomer of carbohydrate

nucleotide

Monomer of nucleic acids made up of a 5-carbon sugar, a phosphate group, and a nitrogenous base

fatty acid and glycerol

monomer of lipids

macromolecule

A very large molecule found in living things

enzyme

A protein that makes a reaction happen QUICKER; decreases activation energy of a reaction.

polysaccharide

polymer of a carbohydrate

glucose

A simple sugar (carbohydrate) that is an important source of energy, example of a monomer of carbohydrate

Active site

Part of an enzyme into which a particular substrate fits.

Substrate

A substance on which an enzyme acts during a chemical reaction.

Product

A substance produced in a chemical reaction

Catalyst

A substance that speeds up the rate of a chemical reaction.

organic compound

a compound that contains the element carbon

disaccharide

A molecule composed of two monosaccharides. Common disaccharides include maltose, sucrose, and lactose.

enzyme-substrate complex

The combination of the enzyme and substrate

Activation energy

The minimum amount of energy needed to start a chemical reaction

Transmit and Store Genetic Information

Function of a Nucleic Acid

Phospholipid

Polymer of Lipid, makes up cell membrane

Cellulose

Carbohydrate found in plants

Active site of an enzyme

the region of an enzyme that attaches to a substrate

Substrate

reactant of an enzyme-catalyzed reaction

Enzymes are

proteins

Reactants

A starting material in a chemical reaction

Products

Ending materials in a chemical reaction.

cell membrane

thin, flexible barrier around a cell; regulates what enters and leaves the cell

phospholipid

A lipid made of a phosphate group and two fatty acids; consists of a hydrophilic polar head and two non-polar hydrophobic tails; forms cell membranes.

lipid bilayer

a thin membrane made of two layers of lipid molecules

hydrophobic

tails of the phospholipid that are repelled by water

hydrophilic

head of phospholipid that attracts water molecules

equillibrium

a condition in which molecules are spread evenly(equally)

passive transport

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

diffusion

movement of molecules from an area of higher concentration to an area of lower concentration.

concentration gradient

the difference in the concentration of molecules across a distance.

osmosis

the process by which water molecules diffuse across a cell membrane from an area of higher concentration to a area of lower concentration.

hypotonic

describes a solution whose solute concentration is lower and water is a higher concentration than inside the cell.

hypertonic

describes a solution whose solute concentration is higher and water concentration is lower than inside the cell.

isotonic

describes a solution whose solute concentration is equal to the solute concentration inside a cell.

facilitated diffusion

the transport of substances through a cell membrane down a concentration gradient with the aid of carrier proteins.

carrier protein

a protein that transports substances across a cell membrane. Then protein is not open at both ends simultaneously.

channel protein

a protein in a cell membrane that extends through the membrane and is open on both ends forming a pore or channel

active transport

the movement of chemical substances, usually across the cell membrane, against a concentration gradient; requires cells to use energy.

sodium-potassium pump

a carrier protein that uses ATP to actively transport sodium ions out of a cell and potassium ions into the cell.

endocytosis

the process by which a cell membrane surrounds a particle and encloses the particle in a vesicle to bring the particle into the cell.

exocytosis

the process by which a substance is released from the cell through a vesicle that transports the substance to the cell surface and then fuses with the membrane to let the substance out.

Fluid Mosaic Membrane Model

Description of cell membrane structure in which phospholipids form a bilayer that has a fluid consistency and is embedded with protein molecules.

cell wall

different than a cell membrane; found in plants, bacteria, and fungi (never in animals)

Vesicle

A membrane bound "bubble" or sac that contains materials involved in transport of the cell.

semipermeable membrane

A membrane that allows some molecules to pass through but does not allow other molecules to pass through.

ATP

energy

with the concentration gradient

from high to low concentration (passive)