bio midterm

i wish i was a dolphin so i wouldnt have to do this

steps of scientific method

1. make an observation

2. form a hypothesis

   1. must clearly establish an alt explanation

   2. must generate testable prediction

3. devise a testable prediction

   1. if, then

4. conduct a critical experiment

5. draw conclusions & make revisions

null hypothesis

• negative statement proposing that there is NO RELATIONSHIP between 2 factors

treatment

• any experimental condition applied to individuals

experimental group

• a group of individuals who are EXPOSED to a particular treatment

• EXPERIMENTED on

control group

• a group of individuals who are treated identically to the experimental group w/ 1 exception

• NOT EXPOSED to the treatment

• NOT EXPERIMENTED on

• experiment is flawed w/o them

variables

• characteristics of an experimental system that are subject to change

• independent or dependent

blind experimental design

• experimental subjects do not know which treatment (if any) they are receiving

double-blind experimental design

• neither the experimental subjects nor the experimenter knows which treatment the subjects are receiving

• NO ONE KNOWS WE’RE ALL BLIND

randomized experimental design

• experimental subjects are randomly assigned treatment

• researchers do NOT give out treatments

replication def

• process of repeating a study

• increases confidence in results

• isolates variables responsible for outcomes

hypothesis def

• proposed explanation for a phenomenon

• testable!

theory definition

• exceptionally well supported hypotheses

• repeatedly tested

• unlikely to be altered

• broad

independent variable

• measurable entity that can be changed as required

• x axis

dependent variable

• created by process being observed

• value cannot be controlled

• y axis

positive correlation

• when 1 variable increases, so does the other

characteristics of life

1. a complex, ordered organization (1 or more cells)

2. transforms energy to work

3. responds to external environment

4. homeostasis

5. growth, development, & reproduction

6. evolution

element def

• a substance that cannot be broken down chemically into other substances

  • think periodic table! gold, carbon, & copper

  • smallest piece of gold (or any element) will still have all the same properties as a bigger piece

atom def

• a bit of matter that cannot be divided any further w/o losing its essential properties

  • if you keep cutting the smallest piece of gold, you’ll start losing its essential properties

  • cannot be seen to the naked eye

nucleus of an atom

• like the thing in the cell that holds genetic info!

• electrons → negatively charged

• protons → pos charged

atomic mass

• made up of combined mass of protons & neutrons

• NO ELECTRONS theyre too light

atomic number

• number of protons found in the atom’s nucleus

isotopes

• atoms w/ the same atomic number (number of protons) but diff mass

• more or fewer neutrons

• charge doesnt change

radioactive atoms

• unstable nuclei

• break down spontaneously

big 4 elements in your body

1. oxygen

2. carbon

3. hydrogen

4. nitrogen

unstable vs stable atoms

• unstable → vacancies in electron shell, or the path electrons travel on

  • more likely to interact w/ other atoms

• stable → all electron shells are filled to capacity!

versatility of carbon

• can share its 4 valence (outermost) electrons w/ up to 4 other atoms

• bons mostly w/ oxygen, nitrogen, hydrogen, & other carbons (4 elements in ur body)

ions def

• charged atoms

• atoms that have lost or gained electrons

• lost → pos charge (bc theyre neg charged

• gained → neg charge (bc theyre neg charged)

molecules def

• groups of atoms held together by bonds

chemical reactions

• forming & breaking of bonds

• reactants → products

covalent bonds

• 2 atoms share electrons

• like the atoms are holding hands <3

• double bond → sharing 2 electrons

• single bond → sharing 1 electron

ionic bonds

• oppositely charged ions attract each other

hydrogen bonds

• bond between slightly pos hydrogen atom (lost electrons) & a slightly neg atom (gained electrons)

• weaker than covalent or ionic ☹

• hydrogen atom + someone else

• makes water cohesive!! thats why spiders can walk on water

hydrogen bonds gives water these cool things

1. cohesion

2. high heat capacity

3. low density when frozen

4. good solvent (things dissolve in water <3)

aciditi

• amount of H+ (pos charged hydrogen ions) in a solution

• measured in pH

acids!!!!!

• pH lower than 7

• more H+ than OH-

• can donate H+ to other chems

• very reactive

• stomach acids, vinegar, cola (things that give u heartburn)

bases!!!

• pH higher than 7

• higher concentration of OH- than H+

• tastes bitter, has a slippery/soapy feel

• baking soda, bleach

pH buffers

• quickly absorbs excess H+ ions (that element makes things acidic/high pH)

• keeps solutions from becoming too acidic

• can release H+ ions to counteract OH- increases (balancing things out)

blood pH

7.4

organic molecules that u eat

• carbohydrates

• lipids (fats)

• proteins

• nucleic acids

carbohydrates

• includes macromolecules

• primary fuel for cells!

• forms much of the structure of cells in all organisms

• mostly carbon, hydrogen, & oxygen

• composed of monosaccharides (simple sugars)

glucose yay

• most important carb

• in bloodstream, can be used as energy or stored as glycogen for later use/converted to fat

disaccharide & polysaccharide

• 2 simple sugars (di) or multiple (poly) joined together

• makes a complex carb

• time-release stores of energy bc theyre harder to digest

what are complex carbs made of

• disaccharides & polysaccharides

• starch (primary form of energy in plants)

• glycogen (important form of energy in animals)

indigestible carbs

• chitin & cellulose

• fiber yay! good 4 u

lipids

• WAY MORE carbon & hydrogen bonds (C-H) than carbs

• insoluble in water & greasy

• hydrogen bonds! so they dont dissolve in water (insoluble)

hydrophobic vs hydrophilic

• phobic → dont like water

• philic → like water

saturated fat vs unsaturated fat

• sat: each carbon in the C-H chain is bound to TWO (2) hydrogen atoms

  • contribute to heart disease & strokes ☹

  • animal fats, meat & eggs

• unsat: at least 1 double bond between 2 carbon atoms in chain

  • crooked shape!

  • plants & fish

trans fat

• partially hydrogenated vegetable oils

• hydrogen atoms have been added to liquid, unsat fat to make it sat, but that gives it a weird shape & transes its gender

cholesterol

• important for cell membranes

• attach to blood vessel walls & makes them thicken (high chol bad)

• cells in liver produce 90% of circulating chol

• steriods! estrogen & testosterone!

• LIPIDS BUT NOT FAT

proteins

• made up of a unique combo of 20 amino acids

  • double string: 1 side always the same, other side unique

• necessary for growth, repair, & replacement of tissue in living organisms

• 9 of 20 amino acids cant be made by the body so they have to be eaten munch munch

protein structure

• primary

  • sequence of amino acids in the chain

• secondary

  • distribution of folds & twists in the chain

• tertiary

  • chain folds again into this shape

• quaternary

  • 2 or more chains bond together!

  • not all chains do this!

enzymes

• initiate & accelerate chemical reactions in the body

• has an active site to fit the substrate

• substrate fits like key in lock, then bond is broken yay!

• lactose is the substrate, lactase is the enzyme

activation energy

• reactions need a push → yay activation energy

• chemical reactions either release or consume energy

• enzymes lower activation energy, yay a catalyst!

things that influence enzymes

1. enzyme & substrate concentration

   1. enzymes & substrate can only increase up to the point where each is bound to another

2. temp

   1. too high? reaction rate drops, enzymes lose their shape (aka denature)

3. pH

   1. high rate close to optimal level, lowers farther you get

4. inhibitors or activators

   1. inhibitors lower rate, activators rises

incorrect amino acid sequences

• active site disruptions, cant work!

• responsible for diseases & problems

nucleic acids

• encode info on how to build & run a body

• composed of nucleotides

  • sugar

  • phosphate group

  • nitrogenous base

• carry genetic info (think like the nucleus)

yay dna

• information is stored in dna sequence

• A goes w/ T, C goes w/ G

  • THIS ALWAYS HAPPENS

• double helix (strands)

yay rna

• takes instructions from dna, moves to another part of cell, boom lets build!

• A goes w/ U NOT T, C still goes w/ G

• single strand

cell

• smallest unit of life

• functions independently & performs all necessary functions of life

  • complex

  • grow, develop, & reproduce

  • transforms energy to work

  • responds to external environment

  • evolves

  • homeostasis

cell theory

• all living organisms have 1 or more cells

• cells arise from other, pre-existing cells (reproduction!)

eukaryotic cell vs prokaryotic cell

• euk

  • nucleus holds cell’s dna

  • organelles

  • 10k times bigger

• pro

  • no nucleus, dna in cytoplasm

  • no organelles

  • tiny

4 basic structural features of a prokaryote

1. plasma membrane

   1. encloses cell contents

2. cytosol

   1. jelly-like fluid inside cell

3. dna

   1. circular loops

4. ribosome

   1. converts genetic info (from dna) into protein structure

phospholipid bilayer

• hydrophilic head (polar & likes water) & hydrophobic tail (nonpolar & scared)

• head is glycerol linked to phosphorus

• tail is carbon-hydrogen chain

• head face out, tails in touching each other

receptor proteins

• bind to external chems that regulate processes in cell

recognition proteins

• provides a fingerprint for identification by other cells

• helps immune system figure out which cells are from the body & which are harmful

transport proteins

• passageway for molecules to enter cell

• little door <3

membrane enzymes

• accelerates chem reactions in plasma membrane

passive transport

• molecules spontaneously diffuse across a membrane

• simple diffusion & facilitated diffusion

simple diffusion

• molecules move DIRECTLY through plasma membrane

• no help needed!

facilitated diffusion

• molecules NEED HELP moving across plasma membrane!

• transport proteins help

• NO ATP SPENT thats the difference between this & active transport

osmosis

• passive transport of water across membrane

• water doesnt need help

osmosis in an ISOtonic solution

• concentration of solute & water is EQUAL yay!

• water movement is balanced

• cell retains shape

osmosis in a HYPOtonic solution

• LOTS of water, not enough solute

• water diffuses INTO cells

• cell swells up, animal cell can EXPLODE

osmosis in a HYPERtonic solution

• LITTLE water, more solute

• water diffuses OUT of cells

• cells shrivel up

active transport

• using energy to transport molecules across a membrane

• primary → uses atp directly

• secondary → transport proteins get atp INDIRECTLY

endocytosis vs exocytosis

• endo → INPUT large particles into cell

  • phagocytosis & pinocytosis

• exo → EXPORT particles

  • vesicles enclose particle & then merge w/ membrane to release

phagocytosis vs pinocytosis

• phag → cell membrane EATS large particle

• pino → cells take in dissolved particles & liquids

receptor-mediated endocytosis

• INPUT large cells by engulfing specific particles

nucleus of a cell

• genetic control center

• stores hereditary info

nucleus structure (3)

1. nuclear membrane

2. chromatin → long, thin fibers that hold dna w/ some proteins attached

3. nucleolus → assembles ribosomes

cytoskeleton

• inner scaffolding of cell (like my skeleton)

• provides shape & support

• controls traffic

• movement!

cilia

• short projections that beat swiftly to move FLUID along & past a cell

flagella

• long tube structures that mov cells through ENVIRONMENT

lysosomes

• garbage disposals

• digesting & recycling cellular waste

rough endoplasmic reticulum

• modifies proteins that will be shipped out

• covered in ribosomes, making them rough! ribosomes make proteins

• wraps around nucleus

smooth endoplasmic reticulum

• synthesizes lipids

• detoxifies molecules (drugs! alcohol!)

• shaped like coral reefs

golgi apparatus

• processes products for delivery

• shaped like wifi signal

plasmodesmata

• tube channels that connect plant cells to each other

• sits on cell wall

vacuoles

• storage sacs!

  • nutrients

  • waste

• also predator deterrence, repro, & physical support

chloroplasts

• do photosynthesis

CHAP 5

I WISH I WAS A FISH

what goes in & out of photosynthesis

• in

  • sun

  • co2

  • water

• out

  • sugar

  • oxygen

cellular respiration

• PLANT CELLS WHO PHOTSYNTHESIZE

• energy is released from chem bonds in food & stored in atp molecules to be used l8r

CHAP 15

IM GOING TO EXPLODE

microbe

• organisms too small to see w/o magnification

• grouped bc theyre small, not rlly bc theyre similar

• most abundant organisms on earth

whats a bacteria

• no organelles

• classified by shape

• reproduce thru BINARY FISSION WOAH

how do you identify bacteria

• appearance

• gram strain

  • gram pos → glycoprotein layer on bacteria is on the outside of cell wall & can be stained w/ purple dye

  • neg → glycoprotein layer lies inside cell wall & membrane, cant be stained

binary fission

• asexual cell division

• produces 2 daughter cells who carry the exact same genetic info as parent

methods of genetic exchange

• CONJUGATION

  • bacterium gives a copy of some or all of its dna to a friend <3

• TRANSDUCTION

  • virus w/ pieces of bacterial dna infects a new bacterium, passing on genetic info

  • similar to passing of genetic info in conjugation

• TRANSFORMATION

  • bacterium takes up dna from it’s surroundings

cyanobacteria & oxygen revolution

• resemble 1st photosynthetic organisms 2.6 billion years ago

• revolution: cyanobacteria release o2 through photosynthesis, yay it’s in the atmosphere now!