Biology - Midterm

Organism

A living thing (uni or multicellular)

Cell

Building blocks of life

Unicellular

Made of a single cell (bacteria, protists, algae)

Mulitcellular

Made up of many cells (all plants and animals, some fungi)

Prokaryote

A unicellular organism that lacks a nucleus

Eukaryote

Organism whose cells contain a nucleus

Prokaryotic cell

-No nucleus (DNA floats in nucleoid region
-1 to 10 pm (smaller)
-No membrane bound organelles
-All have cell wall
-Bacteria, archaea

Eukaryotic cell

-With nucleus
-10 to 100 pm (bigger)
-Many organelles
-Some have cell wall
-Animals, plants, protists, fungi

Cell membrane (plasma membrane)

-Protects the cell and regulates what goes in/out of it
-Separates outside world from inside of cell
-In all cells

Cytosol

-Watery, jelloy consistency fluid inside cell
-In all cells

DNA

-Gives cell its characteristics and abilities (instructions for proteins; curly v. straight hair)
-Genetic material
-In all cells

Ribosomes

-Builds proteins
-In all cells

Organelle

A compartment surrounded by a membrane with its own function (e.g. lysosome, chloroplast)

Asexual reproduction

-Requires only one parent
-Offspring are identical to parent

Sexual reproduction

-Requires two parents
-Offspring are genetic combination of both parent's sperm and egg

Growth

An increase in size and amount of an organism (more cells, not bigger cells)

Development

A series of changes an organism undergoes in reaching its final form
(e.g. butterfly)

Autotroph

-An organism that makes its own food
-Plants, algae, some bacteria

Heterotroph

-An organism that obtains energy from the foods it consumes
-Animals, fungi, some bacteria

Cellular respiration

Process that releases energy from food

Reactant

A chemical substance that is present at the start of a chemical reaction

Product

A substance produced in a chemical reaction

Stimulus

A change in an organism's environment

Response

A reaction to a stimulus

Homeostasis

-Keeping a stable internal environment
-e.g. blood pressure and body water volume

Evolution

Groups of organisms changing over long periods of time

Generation

A group of individuals born and living during the same time

Virus

-Made of genetic material (DNA or RNA) in protein coat (capsid)
-Smaller than cells
-Evolve
-Reproduce using lytic (cell bursts) or lysogenic (cell reproduces virus) cycle

Observation

Something we know through the 5 senses

Hypothesis

-A possible, testable prediction, often based on observations
-Null hypothesis: no relationship between variables

Prediction

-A statement of what you expect to see happen in your specific experiment if your hypothesis is supported
-Often "If my hypothesis is true, then..."

Independent variable

The variable you purposely change or manipulate within the experiment

Dependent variable

The variable you are measuring as a result of the change

Control group

-The group of things that does not receive the change you make
-Used for comparison

Positive control group

Group not exposed to experimental treatment but a different treatment that is known to produce an expected effect

Negative control group

-Group not exposed to experimental treatment; left alone

Treatment group

The group that receives the treatment

Conclusion

-Was hypothesis supported?
-Any alternate hypothesis to explain result?
-How to improve experiment?
-Are results accurate?

Constant

Something that stays the same in an experiment

Characteristics of life

Reproduction, evolution, growth and development, metabolism, made of cells, maintaining homeostasis

All cells have...

Cell membrane, cytosol, DNA, ribosomes

Atom

-The smallest particle of an element that has all of the properties of an element
-Structure: tiny, dense nucleus with electrons orbiting it

Law of Conservation of Mass

Atoms are not created or destroyed during chemical reactions, they get rearranged

Nucleus

The center of an atom; made up of protons and neutrons

Protons

-Positively charged particles
-Equals number of electrons in neutral atom

Neutrons

Neutrally charged particles

Electrons

-Negatively charged particles that move around outside the nucleus of an atom
-Equals number of protons in neutral atom

Valence electron

Electrons on the outermost energy level of an atom

Isotope

Atoms of the same element/same number of protons that have different numbers of neutrons --\> different atomic mass

Ion

Positively and negatively charged atoms

Atomic number

Number of protons

Atomic mass number

Number of protons + neutrons (whole \#)

Atomic mass

The average mass of all the isotopes of an element (decimal \#)

Bohr Model

-Shows number of protons and neutrons in the nucleus and ALL of the electrons in their shells

Lewis Dot Structure

-Element symbol in the middle and shows only valence electrons

Nonpolar covalent bond

Equal sharing of electrons between two atoms with same/similar electronegativity

Polar covalent bond

-Unequal sharing of electrons between two atoms with unequal electronegativity
-Results in the formation of partial charges
-More electronegative atoms gains a partial negative charge, less electronegative gains partial positive charge

Double bond

Two pairs of shared electrons

Triple bond

Three pairs of shared electrons

Ionic bond

-A transfer of 1+ electrons from one atoms to another, electrostatic attraction holds the resulting ions together
-Atoms become ions
-Forms when there is a difference of 1.8 or greater in electronegativity
-More electronegative atom gains the electron(s)

Electronegativity

The ability of an atom to attract electrons towards itself in a chemical reaction

Molecule

Two or more covalently bonded atoms (can be same or different elements)

Compund

A substance made up of atoms of two or more different elements (covalent or ionic bond)

Coefficient

How many molecules or atoms of each reactant and product

Subscript

Shows how many atoms of an element are in a compound

Activation energy

Energy needed to get a reaction started

Endergonic reaction

Non-spontaneous chemical reaction where free energy is absorbed from the surroundings

Exergonic reaction

A spontaneous chemical reaction where energy is released

Reactant

A chemical substance that is present at the start of a chemical reaction

Product

A substance produced in a chemical reaction

Water

-Polar covalent bond (polar molecule)
-Properties: cohesion, adhesion, capillary action, transpiration, universal solvent, high heat of vaporization, amphoteric (neutral pH (7) --\> can act as acid or base)

Polar molecule

A molecule in which one side of the molecule is slightly negative and the opposite side is slightly positive

Hydrogen bond

Weak bond/attraction between a partially positive hydrogen atom and another partially negative atom
(each. water molecule can participate in up to 4 bonds)

Cohesion

Attraction between molecules of the same substance (water molecules stick together with hydrogen bonds)

Adhesion

Attraction between molecules of different substances
(water molecules stick to other substances with hydrogen bonds)

Capillary action

Ability of a liquid to flow through porous material in the opposite direction of gravity (provides leaves with water, allowing them to photosynthesize and create food for the plant)

Transpiration

Evaporation of water from the leaves of a plant

Solute

Substance to be dissolved

Solvent

Substance that dissolves the solute

Heat of vaporization

The amount of energy a substance must absorb to change state from liquid to gas (water has high heat of vaporization; takes a lot of energy to break hydrogen bonds so water can change state)

Evaporative cooling

As a liquid evaporates, its remaining surface cools

pH

Amount of H+ ions available in a solution (acid or base)

Acid

A substance that increases the hydrogen ion concentration of a solution (low pH, 0-7)

Base

A substance that decreases the hydrogen ions in a solution by adding OH- or removing H+ (high pH, 7-14)

Buffer

-A weak acid and its conjugate base that prevents sudden or rapid changes in pH (if you add a base, the acid will takeover, if you add an acid, the base will takeover)
-Either adds or accepts H+ so pH stays the same
-Example of homeostasis; cells use natural buffers to balance pH levels

Amphoteric

A substance that can act as both an acid and a base

pH indicator

Substance that indicates pH via color change (the warmer the color, the lower the pH)

Polymer

Chain of monomers linked by covalent bonds

Monomer

Small unit that makes up a polymer (largest repeating piece)

Macromolecules

-Large molecule
-Elements in them: Carbon, Hydrogen, Oxygen, Nitrogen, Phosphorus, sometimes Sulfur
-Organic
-Carbon atoms always form 4 covalent bonds to form molecules --\> forms chains and rings --\> carbon makes up backbone of macromolecules

Organic

Contains carbon

Carbohydrate

-Elements: CHO
-Monomer: Monosaccharide or Disaccharide
-Fast source of energy
-Ring like structure

Lipid

-Elements: CHO
-Monomers: Glycerol + Fatty acid
-Longterm energy storage
-Make up cell membranes
-Important for insulation

Protein

-Elements: CHONS
-Monomer: Amino acid
-Builds muscle
-Enzymes are proteins
-DNA is the code for protein
-Antibodies \= protein (immunity system)

Nucleic acid

-Elements: CHONP
-Monomer: Nucleotide
-Example: DNA, RNA
-Everything living has DNA, so foods that were once living may have DNA (nucleic acid is in many things)

Dehydration Synthesis

A chemical reaction in which two monomers covalently bond to each other with the removal of a water molecule (build bigger chains)

Hydrolysis

A chemical process that splits a monomer by adding water (break down chains)

Carbohydrate

-Structure: ring/hexagon
-Elements: CHO (Ratio\=CH2O)
-Monomers: mono/disaccarides
-Polymer: polysaccharides

Monosaccaride

-One sugar unit
-Can be linear or rings
-Ex: glucose, fructose, galactose (all isomers with formula --\> C6H12O6)
-Sugars --\> function is to provide energy quickly during cellular respiration
-Monomers

Disaccharide

-2 sugar units (combines monosaccharides)
-Rings
-Ex: lactose, sucrose
-Sugars --\> function is to provide energy quickly during cellular respiration
-Monomers