Biology Midterm

what is the function of the diaphragm?

to control the amount of light that passes through

what objective is used to focus?

the lower power objective

How do you calculate total magnification?

ocular (10x) times objective (4x, 10x, 40x)

why is it a compound mircoscope?

it uses light and multiple objectives

Scientific Method

1. Problem
2. research
3. hypothesis
4. experiment
5. analysis
6. conclusion
7. prediction

what is the difference between constants and variables?

Variables change and constants stay the same.

What is the difference between independent variable and dependent variable?

The IV is something the scientist changes (amount of water given to green beans), the DV changes based on the IV (result; amount of green beans grown).

How do you graph the dependent variable and the independent variable?

X axis- IV

Y axis- DV

Hypothesis

an educated guess made after you do research; an “answer” to the problem/question

Null Hypothesis

the opposite of the hypothesis; used to reject or accept the hypothesis

Placebo Group

typically used on humans; a fake treatment (not known that it’s fake) used to make sure a treatment works

Experimental group

actively participating in the experiment; getting the treatment

Control group

not getting the treatment or the “normal” treatment; used for comparison at the end of experiment

Conclusion

a statement that summarizes exactly what happened in the experiment

What does Chi Square test?

whether you accept or reject the null

When do you accept the null? What does this mean for the hypothesis?

Accept the null when critical value is higher than the X2 value. This mean the hypothesis is incorrect.

When do you reject the null? What does this mean for the hypothesis?

Reject the null when critical value is less than the X2 value. This mean the hypothesis is correct.

nuclear envelope

a phospholipid membrane that surrounds the nucleus; used as protection; has pores to allow things in/out of the nucleus

nucleus

control center of the cell; contains DNA

nucleous

a dense circular structure in the nucleus; produces ribosomes ad RNA

chromatin

when DNA is in long, thin strands in the nucleus

cytoplasm

gel-like fluid that contains the nucleus and other organelles

cell membrane

holds cell together; important for transporting things in/out of the cell; made of phospholipid bilayer, proteins, and cholesterol

cell wall

thick outer layer of PLANT CELLS made of cellulose; used for protection against drying out

lysosomes

clean up the cell; dispose of old organelles, waste, etc.; made by golgi bodies

golgi bodies

5-8 flattened membranes; near the ERs; attach sugar to proteins (glycoproteins-- glycostation) and wrap them up in vesicles to be taken out of the cell; make lysosomes and vesicles

vacuoles

store food, water, or waste; release biomolecules; plant cells have one large vacuole, animal cells have several scattered in the cytoplasm

vesicles

storage, move in/out of cell; made by golgi bodies

Rough ER

surround nucleus; transport things in/out of the nucleus; have ribosomes that make proteins to send to golgis

Smooth ER

surrounds rough ER; transports to/from nucleus; makes lipids, phospholipids, and steriods; store calcium for muscle contraction

chloroplasts

PLANT CELLS; rod-shaped, double membrane; makes energy from photosynthesis; separate DNA/RNA from cell

thylokoids

contain chlorophyll

Grana

stack of thylokoids; where photosynthesis occurs; makes ATP and NADPH to make sugars

stroma

water space between thylokoids; where sugar is made

ribosomes

cell part of rRNA that makes proteins

mitochondria

oval, double membrane (inner membrane called cristae); “power house” of the cell; makes energy through cellular respiration

peroxisomes

membrane-bound organelle; key in the oxidation of biomolecules (breaks down hydrogen peroxide); contribute to biosynthesis of membrane lipids

chromosome

during mitosis/meiosis chromatin coils around proteins forming an X shape

centrioles

2 bundles of microtubes near nucleus; pull apart chromosomes; makes cytoskeleton

cytoskeleton

internal skeleton made of protein fibers

flagella

whip-like structure used for movement

cilia

short hair-like structures found on the outside of cells

Prokaryote

(before nucleus) smaller, no nucleus, no membrane bound organelles, no DNA/RNA or ribosomes, evolved first

Eukaryote

(true nucleus) larger, nucleus, membrane-bound organelles, evolved from prokaryotes

Statements of the cell theory

1. all organisms are made of one or more cells
2. all cells come from pre-existing cells
3. the cell is the basic unit of structure and organization that performs life functions

Endosymbiotic Theory

Eurkaryotes evolved from prokaryotes. Prokaryotes evolved into mitochondria and chloroplasts

animal cell

* scattered vacuoles
* have centrioles
* no chloroplasts
* cell membrane

plant cell

* one, central vacuole
* no centriole
* chloroplasts
* cell wall and cell membrane

DNA

* deoxyribose
* TACG
* double helix
* stays in nucleus
* more stable
* gene and proteins
* master blueprint (protected)
* evolved second

RNA

* ribose
* TUCG
* single helix
* moves between nucleus and cell
* less stable
* more functions
* cheap copy (disposable)
* evolved first

covalent bond

strongest bond, result of sharing electrons, results in a molecule (polar or non polar)

H2O, CO2

ionic bond

strong dry, weak wet, form between metal and non metal, results from swapped electrons, cations (+) and anions (-)

NaCl, CaCl2

hydrogen bond

weakest bond, formed between positively and negatively charged atoms/molecules, most important

Bond between water molecules

ions

charged atom; when number of protons and electrons are different

isotope

atoms with too many/few neutrons; unstable

potential energy

stored energy, energy of position, when electrons are locked in a chemical bonds, like a battery

kinetic energy

energy of motion; when electrons are freely moving

Biomolecules

* carbohydrate (sugar)
* lipids (fat)
* proteins
* nucleic acids (DNA/RNA)

monomer

one, building block of polymers

polymer

many, made of monomers; joined by covalent bonds

dehydration synthesis

forms bonds by removing water

hydrolysis

breaks bonds by adding water

polarity

high electronegativity of oxygen and low electronegativity of hydrogen causes the oxygen side to be negative and the hydrogen side to be positive

makes water a conductor and an excellent solvent

cohesion

when water sticks to water; hydrogen bonds between water molecules

capillary action

when water molecules stick together and move upward in plant cells

adhesion

when water sticks to another molecule or substance

surface tension

the ability of the surface of water to resist an external force

high specific heat

water heats slowly and releases heat slowly; water is cold during the day and warm at night

evaporative cooling

as water evaporates off your skin it has a cooling effect

expansion when freezing

water expands and becomes less dense when it freezes

unviversal solvent

water has the ability to dissolve more substances than any other liquid

What is the ultimate source of nitrogen?

atmospheric nitrogen

Explain Nitrogen fixation

nitrogen fixing bacteria, that is near the roots of plants, that takes NO2 and converts it into ammonium

Denitrofixation

other bacteria takes nitrates and converts it back into NO2

How do humans get usable nitrogen?

by eating plants or herbivores

Why do we need nitrogen?

to make nucleic acids and proteins

Carbohydrates

* CHO
* monosaccharides
* fast energy

Lipids

* CHO
* fatty acids and glycerol
* slow energy

Proteins

* CHNO(S)
* animo acids
* muscle building, molecular transport, cell to cell communication

nucleic acids

* CHNOP
* nucleotides
* DNA/RNA

What is the ultimate source of phosphorus?

weathering rocks

Why do humans need phosphorus?

it is used in cell membranes

How does phosphorus enter soil and water?

as rocks weather, wind and rain carry it into soil and water

CHNOPS:

carbon, hydrogen, nitrogen, oxygen, phosphorus, sulfur

chaperonin

a structure that allows proteins to refold inside without the presence of water

what turns ATP into ADP?

hydrolysis

What turns ADP into ATP?

dehydration synthesis

primary structure

* chain of amino acids joined by covalent bonds
* can’t denature

secondary structure

* foiling (beta pleats) and coiling (alpha helix) caused by hydrogen bonds
* can denature

tertiary structure

* disulfide bridges to stabilize proteins
* have cystenine
* can denature

quaternary structure

* when two or more polypeptides are joined together

6CO2 + 6H2O → C6H12O6 + 6O2

formula for photosynthesis

C6H12O6 + 6O2 → 6CO2 + 6H2O

formula for cellular respiration

what kind of relationship do plants and animal cells have?

symbiotic relationship

Sources of CO2

factory emissions, plant respiration, animal respiration

sources of carbon in soil

decaying organisms, root respiration, fossil fuels

Why is there an inbalance of CO2 in the atmosphere?

fossil fuels and factory emissions

What is the only way to remove CO2 from the atmosphere?

photosynthesis

How do humans get carbon?

by eating plants that have it

Why do we need carbon?

it makes the biomolecules