life120 exam 1

core concepts in biology

1. life evolves overtime

2. matter and energy are transformed

3. biological processes go through information flow

4. structure and function are interconnected

5. biology consists of complex systems

macro similarities/differences

at the surface

micro similarities/differences

inner structures

what micro/macro similarities/differences prove

accounts for the unity and diversity of life

fossil record

• indicates that life has changed over the course of the earth’s history

• shallow layer = newer

• deeper layer = older

descent with modification

• differences from ancestry due to change in environment over time

• produces adaptation to a local environment

natural selection

survival of the fittest

sexual selection

reproductive mate selection provides selective pressure

viral evolution

virus changes its genetic code overtime to adjust to the environment

artificial selection

humans provide selective pressure

biological organization

1. biosphere

2. ecosystem

3. communities

4. populations

5. organisms

6. organ

7. tissue

8. cell

9. organelles

10. molecules

biosphere

all life and the places where life exists on earth

ecosystem

living and nonliving things in a specific area

communities

array of organisms in a particular ecosystem

population

all individuals of specific species living in specific area

organisms

individual living things

organs

body part made of multiple tissues with specific function

tissues

clumps of cells that work together to carry out a specific function

cells

fundamental aspect of function and structure in life

organelles

inner structures in a cell

molecules

chemical structure with 2+ units of atoms

emergent properties

properties that occur when arrangement and interactions of parts become more complex

emergent properties examples

• biosphere: nutrient cycling and climate regulation

• ecosystem: interactions between living and nonliving

• communities: array of organisms interacting

• population: group dynamics, collective behavior

• organisms: homeostasis and complex behavior

• organ: organ function

• tissue: coordinated tissue capability

• cell: life itself

• molecule: metabolic function

how can natural selection lead to two populations with features that are uniquely adapted to their environments

as the members of these two populations, who have traits that make it easier for them to survive to a specific environment, reproduce, their offspring inherits these traits and the cycle keeps going until these populations are fully adjusted

element

• substance that can’t be broken down to other substances

• comprised of single type of atom

compound

substance consisting of 2+ elements in a fixed ratio

composition of body

• mainly oxygen

• there is mostly water in our bodies = more oxygen

atoms

• smallest unit of matter that retains properties of element

• protons (identity of an atom), neutrons, electrons

• neutral state = equal amount of protons and electrons

atomic number

• number of protons

• subscript (₆C)

mass number

• protons + neutrons

• superscript (⁶C)

dalton

• unit of weight for atoms (1.7 × 10^-24)

• protons and neutrons = 1 Da each

isotopes

elements with different number of neutrons

carbon-14

• used to date archeological samples

• earth’s atmosphere contains small and constant amount of c-14

• in metabolic processes until death

• half-life = 5,000

electrons and shells

• occupy discrete shells

• gains or loses energy to move across shells

• inner shell = lower energy, making electrons more inclined to go towards its direction

valence electrons

• electrons occupying outermost shell

• determines the chemical behavior of an atom

• atoms are more stable when their valence shell is fully occupied w/ electrons

amount of electrons in each shell

• 1st shell = 2 electrons

• 2nd and 3rd = 8 electrons

covalent bonds

atoms held together through shared valence electrons

molecule

2+ held together by covalent bonds

single bond

one pair of shared electrons

double bond

two pairs of shared electrons

electronegativity

tendency for an atom to attract shared electrons

FONCl BrISCH

• fluoride

• oxygen

• nitrogen

• chlorine

• bromine (END OF HIGH)

• iodine

• sulfur

• carbon

• hydrogen

non-polar covalent bonds

small electronegativity

polar covalent bonds

high electronegativity

water and covalent bonds

• contains two polar covalent bonds

• partial negative in oxygen, partial positive for hydrogen

ionic bonds

• attraction between opposite charges that occur when an electron is transferred from one atom to another

• holds ionic compounds together

hydrogen bonds

result from attraction of partially positive hydrogen with partially negative charge on electronegative atom

van der waals interactions

attraction between nonpolar molecules based on transient regions of positive and negative charges

properties of water

1. water has strong adhesion, cohesion, and surface tension

2. resists temperature changes

3. ice is less dense than water

hydrophilic substances

• loves water

• fully/partially charged

hydrophobic substances

• hates water

• uncharged and nonpolar

acid

substance that donates H⁺ ions

base

substance that depletes H⁺ ions

pH scale

• measure of hydrogen ion concentration

• pH = -log[H⁺]

• more H⁺ = more acidic, lower pH

• less H⁺ = more basic, higher pH

classes of molecules

• humans are also mostly carbon-based

  • basis of molecules

• four classes

  • carbohydrates

  • lipids

  • nucleic acids

  • proteins

• macromolecules: only carbs, nucleic acids, and proteins because they are able to form long polymer structures

polymer

repeating units linked by covalent bonds

monomer

building blocks of polymers

dehydration synthesis

removing water polymers to bond two polymers together

hydration synthesis

adding water to break down polymers

polymer diversity

diversity in variation of polymers is based on amount of monomers

• ex: for dna, the 4 nucleotides and 10 polymers = 4¹⁰

carbohydrates

• function: store energy, energy source, cell structure

• composition: includes sugars and sugar polymers

• structure of carbohydrate affects function

  • ex: starch can be digested but cellulose can’t

lipids

function: energy storage, warmth, padding

composition: mostly non-polar hydrocarbons

saturated and unsaturated fats

• structure: glycerol + three fatty acid chains

• saturated fats: sold, dense, straight structure

• unsaturated fats: liquid at room temperature, kink in the structure

phospholipid

• structure: glycerol + two fatty acid chains + phosphate

• hydrophilic head, hydrophobic tail

lipid bilayers

prevent the passage of hydrophobic substance

proteins

• function: enzymes, communication, storage, transport, structure, defense, movement

• composition: amino acids linked into polypeptides

amino acids

• organic molecules w/ carboxyl and amino groups

• 20 amino acids vary in their r groups

enzymatic proteins

selectively speed up reactions

defense proteins

protect against disease

storage proteins

store amino acids

transport proteins

transport substances

hormonal proteins

coordination of organisms activities

structural

support

peptide bond

• covalent bond between two amino acids

• amino acids are joined to form polypeptides

polypeptides and folding

• fold to form functional proteins

• how it folds

  • ionic bonds

  • hydrophobic (inside) and hydrophilic (outside) bonds

primary structures

sequence of amino acids that are covalently bonded

secondary structures

folding of alpha helixes (coils) and beta pleated sheets (folds) in a polypeptide that are hydrogen bonded in place

tertiary structure

determined by interactions among amino acids and R groups/side chains

quaternary structure

• bonding of multiple polypeptides into one structure

• doesn’t occur for every protein

nucleic acid

• function: information storage and transport

• composition: nucleotides linked together into polynucleotides

DNA bases

• pair w/ each other to form double-stranded helix

• adenine and thymine

• guanine and cytosine

RNA

• ribose sugar

• single stranded

• uses uracil instead of thymine

predict how many covalent bonds an atom (hydrogen, oxygen, nitrogen, carbon) will form with other atoms in a molecule

• hydrogen: one bond

• oxygen: two bonds

• nitrogen: three bonds

• carbon: four bonds

match following structures

1. carbohydrate

2. protein

3. nucleotide

4. lipid

components of macromolecules

• carbs: carbon, hydrogen, oxygen

• protein: amino acids

• nucleic acids: nucleotides

• lipids: hydrocarbon chains, oxygen

cells

• fundamental units of life

components of cells

• all organisms are made of cells

• the cell is the simplest collection of matter that can be alive

• all cells are related by their descent from earlier cells

• can differ substantially from each other, but share common features

magnification

get closer

contrast

intensity between two adjacent points

resolution

distance between two adjacent points and how close/far it takes to distinguish it as two entities

light microscope

• uses visible light and beams it through specimen and then through class lenses

• refracts light so image becomes magnified

• staining and labeling enhance contrast

benefits/limitations of light microscope

benefits: cheaper, living organisms

limitations: can’t see inside

electron microscope

use electrons to produce image

scanning electron microscopes

beams electrons on specimen’s surface to create 3D strucutre

transmission

beams electrons through a specimen

benefits/limitations of electron microscope

• benefits: can see inside organisms

• limitations: can’t use living organisms, expensive

life is classified into two cell types

• prokaryotes

  • bacteria

  • archaea

• eukaryotes

  • protists

  • fungi

  • plants

  • animals

prokaryote traits

• small

• no membrane-bound organelles

• single-celled organisms

• no nucleus, DNA kept in unbound nucleoid region

• most have call wall

eukaryote traits

• larger cells

• multicellular

• DNA in nucleus, surrounded by nuclear envelope

• some plants have cell wall (plants, algae)

both prokaryotes and eukaryotes

• plasma membrane

• cytosol

• chromosomes

• ribosomes