Bio Midterm

Words that you should know

Observation

The act of noticing and describing events or processes in a careful, orderly way.

Inference

A logical interpretation based on prior knowledge and experience.

Hypothesis

Possible explanation for a set of observations or possible answer to a scientific question; a tentative, educated guess.

controlled experiment

An experiment in which only one variable is manipulated at a time.

Independent Variable

changed factor in a controlled experiment; variable that is manipulated

Dependent Variable

The outcome factor; the variable that may change in response to manipulations of the independent variable.

Control Group

In an experiment, the group that is not exposed to the treatment; contrasts with the experimental group and serves as a comparison for evaluating the effect of the treatment.

Data Theory

Provides abstract models for understanding the information conveyed by real world observations.

Scientific Theory

a well-tested explanation for a set of observations or experimental results

Bias

Favor against one side

Biology

The study of life

Sexual Reproduction

the production of new living organisms by combining genetic information from two individuals of different types.

Asexual Reproduction

a mode of reproduction in which a new offspring is produced by a single parent.

DNA

stores genetic information; the replicated genetic information during the interphase of mitosis

Metabolsim

the process in which the body changes food and drink into energy

Stimulus

anything that can trigger a physical or behavioral change.

Homeostasis

when an organism can maintain internal stability while adjusting to changing external conditions

Evolve

develop gradually, especially from a simple to a more complex form.

Atom

the basic units of matter; made up of protons, neutrons, and electrons.

nucleus

the center of the atom; holds genetic information (DNA)

Electron

A negatively charged particle that is on the outside ring of an atom

Element

A pure substance made of only one kind of atom

Isotope

Atoms of the same element that have different numbers of neutrons

Compound

substance formed by the chemical combination of two or more elements in definite proportions

Ionic Bond

Formed when one or more electrons are transferred from one atom to another

Ion

An atom or group of atoms that has a positive or negative charge.

Covalent Bond

A chemical bond formed when two atoms share electrons; travel about the nuclei of both atoms.

Molecule

two or more atoms held together by covalent bonds

van der Waals forces

a slight attraction that develops between the oppositely charged regions of nearby molecules; briefly send out signals and carry out chemical reactions

Hydrogen Bond

Attraction between a slightly positive hydrogen atom and a slightly negative atom.

Cohesion

Attraction between molecules of the same substance

Adhesion

An attraction between molecules of different substances

Mixture

A combination of two or more substances that are not chemically combined

Solutions

When ions gradually become dispersed in water.

solute

A substance that is dissolved in a solution.

solvent

the substance in which the solute dissolves

Suspension

mixture of water and non-dissolved material

pH scale

measurement system used to indicate the concentration of hydrogen ions (H+) in solution; ranges from 0 to 14

Acid

any compound that forms H+ ions in solution; (lower than 7)

Base

compound that produces hydroxide ions (OH-) in solution; solution with a pH of more than 7

Buffer

weak acid or base that can react with strong acids or bases to help prevent sharp, sudden changes in pH

monomer

A simple compound whose molecules can join together to form polymers; glucose, fructose, galactose

polymer

large compound formed from combinations of many monomers; starch cellulose, glycogen

carbohydrate

compound made up of carbon, hydrogen, and oxygen atoms; major source of energy for the human body

Lipids

fats, oils, an waxes; used to store energy

some are important in the biological membranes and waterproof coverings

Nucleotides

consist of three parts: a 5-carbon sugar, a phosphate group, and a nitrogenous base

Nucleic Acids

macromolecules containing hydrogen, oxygen, nitrogen, carbon, and phosphorus; store and transmit genetic information

Proteins

Some proteins control the rate of reactions and regulate cell processes. Others form critical cellular structures, while still others transport substances into or out of cells to help fight disease.

Amino acids

compounds with an amino group (-NH2) on one end and a carboxyl group (COOH) on the other end.

Our body uses the proteins to create amino acids and uses dehydration synthesis to form our own proteins.

Peptide bonds- are covalent bonds that link amino acids together to form a polypeptide.

A protein is a functional molecule built from one or more polypeptides.

Cells

Basic unit of life; the smallest units of life

Cell theory

1. All living things are made up cells are of cells

2. Cells are the basic unit of structure and function in living things

3. New cells are produced from existing cells

Cell membrane

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

Nucleus

The nucleus contains nearly all of the cell's DNA (including the coded instructions for making proteins and other essential molecules).

The nucleus controls most cell processes

The nucleus is surrounded by a membrane (the nuclear envelope)

Nuclear pores allow material to move into and out of the nucleus

The nucleolus is in the center of the nucleus

Eukaryote

A cell that contains a nucleus and membrane bound organelles

Prokaryote

A unicellular organism that lacks a nucleus and membrane bound organelles

Cytoplasm

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

Ribosomes

site of protein synthesis; makes proteins

Endoplasmic Reticulum

cell structure that forms a maze of passageways in which proteins and other materials are carried from one part of the cell to another. (protein synthesis and transport, protein folding)

Golgi apparatus

A system of membranes that modifies and packages proteins for export by the cell

Vacuole

Central vacuole stores water, sugar, salt, protein, and carbohydrates, and are found in animal and plant cells

The contractile vacuole continually fills with excess water from the cytoplasm and then expels itCentral vacuole stores water, sugar, salt, protein, and carbohydrates, and are found in animal and plant cells

The contractile vacuole continually fills with excess water from the cytoplasm and then expels it

Lysosome

cell organelle filled with enzymes needed to break down certain materials in the cell; waste (found in animal cells)

Cytoskeleton

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

Chloroplasts

Capture energy from sunlight and use it to produce food for the cell (Green, Plant Cells [chlorophyll] that go through photosynthesis)

Mitochondria

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

Cell Wall

A rigid layer of nonliving material that surrounds the cells of plants and some other organisms.

Lipid bilayer

flexible double-layered sheet that makes up the cell membrane and forms a barrier between the cell and its surroundings

Seletively permeable

A property of cell membranes that allows some but not all of the organisms to pass through

Homeostasis

relatively constant internal physical and chemical conditions that organisms maintain

Diffusions

net movement from higher concentration to lower concentration; occurs across a membrane or within a solution- eventually reach an equilibrium

Facilitated Diffusion

Movement of specific molecules across cell membranes through protein channels

Aquaporin

A membrane protein, specifically a transport protein, that facilitates the passage of water through channel proteins.

Osmosis

Diffusion of water through a selectively permeable membrane

Isotonic

when the concentration of two solutions is the same

Hypertonic

when comparing two solutions, the solution with the greater concentration of solutes

Hypotonic

when comparing two solutions, the solution with the lesser concentration of solutes

Osmotic Pressure

pressure that must be applied to prevent osmotic movement across a selectively permeable membrane

Tissue

A group of similar cells that perform the same function.

Organ

A collection of tissues that carry out a specialized function of the body

Organ System

group of organs that work together to perform a specific function

Receptor

protein that detects a signal molecule and performs an action in response

Cell Division

process in which a cell divides into two new daughter cells

Asexual Reproduction

A reproductive process that involves only one parent and produces offspring that are identical to the parent.

sexual reproduction

A reproductive process that involves two parents that combine their genetic material to produce a new organism, which differs from both parents

Ratio of Surface Area to Volume in a cell

divide the surface area by the volume.

Chromosomes

a threadlike structure of nucleic acids and protein found in the nucleus of most living cells, carrying genetic information in the form of genes.

Chromatin

Substance found in eukaryotic chromosomes that consists of DNA tightly coiled around histones

Cell Cycle

series of events that cells go through as they grow and divide

Interphase

period of the cell cycle between cell divisions