Biology Semester Exam Study Guide

What are the steps of the scientific method?

1. problem
2. hypothesis
3. procedure
4. analyze
5. conclusion

What is an hypothesis?

An educated guess

independent variable

The experimental factor that is manipulated; the variable whose effect is being studied.

dependent variable

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

Which axis does the independent variable go on?

x-axis

On which axis does the dependent variable belong?

y-axis

What is a control group?

the group that does not receive the treatment

The eight characteristics of life

Cellular organization.

Reproduction

Metabolism

Homeostasis

Heredity

Response to stimuli.

Growth and development.

Adaptation through evolution.

ionic bond

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

covalent bond

A chemical bond that involves sharing a pair of electrons between atoms in a molecule

Why are hydrogen bonds important?

They cause water to be attracted to each other.

Cohesion

Attraction between molecules of the same substance

Adhesion

An attraction between molecules of different substances

capillary action

the attraction of the surface of a liquid to the surface of a solid

surface tension

A measure of how difficult it is to stretch or break the surface of a liquid

Why does oil and water not mix?

oil is non polar and water is polar

Mixture

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

Parts of a solution

solute and solvent

Solution

A mixture that forms when one substance dissolves another.

Suspension

A mixture in which particles can be seen and easily separated by settling or filtration

Ions

Charged atoms

Example of an Ion

Sodium, Chloride, and calcium

Isotopes

Atoms of the same element that have different numbers of neutrons

Example of an isotope

Carbon-12, Carbon-13, Carbon-14

What does the pH scale measure?

how acidic or basic a substance is

Difference between acids and bases

acids have more hudrogen ions and bases have more OH ions

Buffers

substances that minimize changes in pH

Parts of a chemical reaction

reactants and products

catalyst

substance that speeds up the rate of a chemical reaction

What is the function of an enzyme

increase rate of reaction

What is the relationship between an enzyme and substrate?

Enzymes are proteins that act upon substrate molecules.

Carbohydrates

the starches and sugars present in foods

Carbohydrates: Monosaccharides

glucose, fructose, galactose

Carbohydrates Functions

energy and structure

Lipids

fats and oils

Lipids monomer

glycerol and fatty acids

Lipids function

store energy

Proteins

Chains of amino acids

Proteins function

build, maintain and repair tissue in body

nucleic acids

DNA and RNA

Nucleic Acids functions

store and transmit genetic information

What are the three components of the cell theory?

1. All living things are made up of cells
2. cells are the basic unit of life
3. new cells are produced from existing cells

The two main types of cells

Prokaryotic and Eukaryotic

Nucleus

Control center of the cell

Mitochondria

Powerhouse of the cell

Rough Endoplasmic Reticulum

transport and storage

Smooth Endoplasmic Reticulum

creates lipids or fat

Ribosomes

site of protein synthesis

Chloroplast

Site of photosynthesis

Vacuole

A sac inside a cell that acts as a storage area

cell membrane

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

cell wall

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

Golgi apparatus

stack of membranes in the cell that modifies, sorts, and packages proteins from the endoplasmic reticulum

Cytoplasm

the portion of the cell outside the nucleus

Which organelles of a plant cell do cellular energetics process occur?

Mitochondria and Chloroplasts

Which organelles of an animal cell do cellular energetics process occur?

Mitochondria

What is the purpose of the cell membrane?

Regulates what enters and leaves cell, provides protection, and provides support.

What three macromolecules make up the cell membrane?

Phospholipids, proteins, and carbohydrates

What macromolecules are phospholipids?

lipids

How does diffusion work?

particles move from an area of high concentration to an area of low concentration

How does osmosis work?

It occurs when water is diffused through a semipermeable membrane from an area of greater concentration to an area of lesser concentration

Hypertonic

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

Hypotonic

Having a lower concentration of solute than another solution

Isotonic

when the concentration of two solutions is the same

What is the difference between active and passive transport?

Active transport requires energy for the movement of molecules whereas passive transport does not require energy for the movement of molecules.

passive diffusion

movement of substances across a semipermeable membrane with the concentration gradient; this process does not require energy

Osmosis

diffusion of water

facilitated diffusion

Movement of specific molecules across cell membranes through protein channels

Protein pump (active)

transmembrane proteins

Endocytosis

process by which a cell takes material into the cell by infolding of the cell membrane

Exocytosis

Process by which a cell releases large amounts of material

What molecule on the cell membrane allows for facilitated diffusion and active transport to occur?

Carrier Proteins

Homeostasis

A tendency to maintain a balanced or constant internal state; the regulation of any aspect of body chemistry, such as blood glucose, around a particular level

Describe two types of feedback mechanisms

Positive and Negative