biology exam 1

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what does it mean to say that something is alive

1. Cells: all organisms are made up of membrane bound cells

2. replication: All organisms are capable of reproduction

3. Information: All organisms inherit traits as well as information from environment.

4. Energy: All organisms acquire and use energy.

5. Evolution: populations of organisms are continually evolving.

The Cell theory

1. All organisms are made of cells.

2. All cells come from preexisting cells.

What can does the cell theory tell us

All cells and all organisms are related by a common ancestry.

Evolution

Change in the characteristics of a population over time.

Natural Selection

explains how evolution occurs

Population

a group of individuals of the same species living in the same area at the same time.

Natural selection requirements

1. individuals vary in heritable charcteristics

2. in a particular environment, certain heritable traits help individuals survive better and reproduce more than others

Evolutionary change

A change in a population over time as beneficial, heritable traits become more common because individuals with those traits produce more offspring.

How are all organisms related?

If all cells come from preexisting cells, then all organisms share common ancestry and are related.

Phylogenetic Tree

A diagram that shows the evolutionary relationships among organisms.

What are the three major groups on the Tree of Life?

1. Eukarya

2. Bacteria

3. Archaea.

What are eukaryotes?

Organisms whose cells have a nucleus. They belong to Eukarya.

What are prokaryotes?

Organisms whose cells lack a nucleus. The two groups are Bacteria and Archaea.

Theory

explanations for broad patterns

Hypothesis

testable statement that explains something observed

experiment

allows researchers to test the hypothesis

prediction

• measurable or observable result

• must be correct if hypothesis is valid

the nature of science

all experimental scientists ask questions that can be answered by measuring things by collecting data.

hypothesis testing

two step process:

1. state hypothesis as precise as possible and list predictions it makes

2. design observational or experimental study capable of testing those predictions

atomic number

number of protons

mass number

number of protons + neutrons

rule of 2

The first electron shell (s orbital) is stable when it has 2 electrons.

rule of 8

Atoms are most stable when their outer shell has 8 valence electrons.
2 in s + 6 in p = 8

covalent bond

when two atoms get a filled out shell by sharing electrons

(not always shared equally)

ionic bond

The attractive force that pulls positive and negative ions together.

Ion formation

the events where an atom gains or loses electrons to get stable, full outer shell

types of covalent bonds

single bonds, double bonds, triple bond

non polar covalent bond

elections are halfway between two atoms sharing equally

polar covalent bonds

electrons aren’t shared equally one is more electronegative so partial charges exist on both atoms

properties of water structure

• small size

• bent shape

• high polar covalent bonds

• overall polarity

water is polar

oxygen atoms have partial negative charge

hydrogen stoms have partial postive charge

hydrophilic

• water loving molecules,

• polar and charged

• ions and polar molecules stay in solution due to their interactions with water’s partial charges

hydrogen bond

weak electrical attraction between slightly positive hydrogen and slightly negative other atom

hydrogen bonding makes it possible for almost any charged or polar molecule to dissolve in water.

true

hydrophobic

• water fearing

• uncharged and non polar compounds that don’t dissolve in water

adhesion

attraction between unliked molecules

cohesion

attraction between like molecules

surface tension

caused by cohesion at surface

other properties of water

Density : water is more dense as a liquid than a solid

high specific heat: energy needed to raise temperature of the solution

high heat of vaporization: energy needed to convert liquid to a gas

macromolecules of the cell

proteins

nucleic acids

carbohydrates

lipids

proteins 6 major functions

1. catalysis: enzymes speed up chemical reactions

2. defense: antibodies and complement proteins attack pathogens

3. movement : motor and contractile proteins move the cell or molecules within the cell

4. signaling : proteins convey signals between cells

5. structure : structural proteins define cel shape and comprise body structures

6. transport : transport proteins carry materials; membrane proteins control molecular movement into and out of the cell

amino acids

building blocks of protein, linked together in long chains by peptide bonds

protein structure

primary, secondary, tertiary, quaternary

Nucleotide is made up of what

Phosphate connected to 5 carbon sugar, 1 carbon sugar bonded to nitrogenous base