bio midterm

What does shape determine for proteins?

function; each kind of protein in a cell has a unique structure and shape

what is biology?

study of life past and present

what is life?

difficult to explain, complex; life emerges from interactions of simple parts

three key features of living things:

requirement for energy and nutrients, homeostasis, use of DNA as hereditary material

1.) requirement for energy and nutrients

Life is sustained by ongoing inputs of energy and nutrients.

2.) homeostasis

each living things has the capacity to sense and respond to change

3.) Use of DNA as hereditary material

DNA is passed to offspring during reproduction

Nutrients

substance an organism needs to grow and survive but can not make itself ex. water, minerals(calcium), proteins, carbohydrates, fats, and vitamins(D is the only one we can make on our own)

Homeostasis

maintaining a stable internal environment; normal body temp 37 degrees C (98.6 degrees F)

How does homeostasis work?

organisms sense changes and react ex. body temp(sweating/shaking), illness, and food

Consumers

organisms that get energy and nutrients by feeding on other organisms; can't make their own food

Producers

organisms that make their own food using energy and materials in their environment ex. mainly photosynthesis

growth

an increase in the number, size, and volume of cells

development

a process where the first cell of a new organism gives rise to an adult

reproduction

the process by which parents produce offspring

inheritance

transmission of DNA to offspring

Organize life into levels

atom, molecule, cell, tissue, organ, organ system, organism, population, community, ecosystem, bioshpere

atom

nonliving, building block of all substances

molecules

made up of 2 or more atoms together

cell

can be a full organism; smallest unit of life

tissue

cells organized to serve a collective function(need to put they work together)

organ

2 or more tissues that work together to serve a function

organ sytem

a set of organs that work together to keep a body working

organism

an individual of one or more cell

population

a group of individuals of the same species in an area

community

all populations of all species in an area

ecosystem

a community plus the physical environment

Bioshpere

all regions of earth where organisms live a.k.a. the earth

protons

symbol: p+; mass: 1amu; positively charged; found in nucleus(center of atom); determines what type of atom it is(change the proton change the atom)

neutron

symbol: n0; mass: 1amu; neutral charge; found in nucleus(center of atom); sometimes atoms of the same elements can have different \# of neutrons a.k.a. an isotope

electron

symbol: e-; mass: about 0amu; negatively charged; found in the electron cloud; determines how the atom bonds and reacts

electron cloud

surrounding the nucleus; massive; most of the atoms volume

Charge within atoms

most atoms are neutral; when unequal: an ion

atoms that are neutral in charge

same amount of protons as electrons

atoms that are positively charged

loss of electrons

atoms that are negatively charged

gain of electrons

ion

formed when an atom loses or gains an electron; charged atom

Anion

A negatively charged ion

Cation

A pawsitively charged ion

Element

pure substance made of atoms that all have the same number of protons; determined by atomic number

atomic number

the number of protons an atom has (know how to find it)

mass number

number of neutrons and protons in an atom

temperature

measure of molecular motion

Orbitals

space outside of the nucleus; think about orbitals like levels/shells around the nucleus

Electrons fill orbitals

fill the orbitals closest to the nucleus first; further the electron for the nucleus the more energy it has; atoms want each level to be filled or empty a.k.a. stable; electrons dont follow set paths

what leads to chemical reactivity in atoms

if the orbitals aren't full, atoms try to fill or empty them to be stable

Chemical bond

attractive force between two atoms; arises from interactions between their electrons; how you move from atoms to molecules ex. cholesterol

Polarity

the seperation of charge into positive and negative charge; happens from the unequal sharing of electrons

Polar molecule

a molecule that has electrically charged areas; the bonding is not equally shared between the atoms; neutral molecules with a difference of charge across the molecule

Electronegativity

the ability of an atom to pull electrons away from other atoms(how good it is at stealing electrons)

Bonds between atoms

ionic bonds and covalent bonds

Ionic bonds

strong mutual attraction between ions of opposite charges(positive to negative); completely lost/gained electrons; each ion retains its own respective charge(polar); ex. NaCI (table salt)

covelant bond

sharing of electrons between atoms; can be polar or nonpolar depending on the electronegativities of atoms in the bond(how well the sharings going)

how can covalent bonds be shown

can be shown as lines between bonds; number of lines = number of bonds; extra electrons not in bonds are shown as dots; dots = electrons and lines = bonds

what type of bond is formed whenever atoms share a pair of electrons?

double covalent

Molecular oxygen is composed of two oxygen atoms that share four electrons. How many covalent bonds exist between the two oxygen atom?

two

Solute

the substance dissolved in other substance ex. salt(solute) + water(solvent) = salt water(solution)

solvent

the substance used to dissolve the solute ex. salt(solute) + water(solvent) = salt water(solution)

Solutions can be...

acidic or basic

Solution

a mixture that forms when one substance dissolves into another

acids release...

H+ when dissolved

what accepts the H+ released from acids

bases

What does a low pH have lots of?

H+

what does a high pH have lots of?

OH

water bonds

water has 2 polar covalent bonds per molecule; oxygen is partially negative and hydrogen is partially positive; leads to attractions between water molecules a.k.a. hydrogen bonds; they want to fill all of the "levels"(orbitals); each end of a water molecule has a slight electric charge; water is a compound

compound

A type of molecule made up of atoms of two or more different elements joined by chemical bonds

What holds the hydrogen atoms to the oxygen atoms?

covalent bonds

How does the density of electrons around the oxygen atom compare to the density of electrons around the hydrogen atom?

There's more density(electrons) around the oxygen atom

Where's the majority of negative charge on the water molecule?

in the electron cloud around the oxygen

acidic levels

ranges from 0-14; lower numbers are acidic(0-6); higher numbers are (8-14); 7 is neutral ex. water; the further from neutral in either direction the more dangerous

Hydrogen bonds

attraction between a covalently bonded hydrogen atom and another atom taking part in a seperate covalent bond; they're 5% the strength of covalent bonds(break easily;individually weak, collectively strong); stabalize DNA and proteins

What gives water its important properties?

attraction among its polar molecules a.k.a. extensive H-bonds (hydrogen bonds)

Properties of water

cohesion, adhesion, capillary action, surface tension, universal solvent, high specific heat(helps your body to maintain a constant internal environment)

cohesion

water "sticking" to itself with weak bonds; bc of this water molecules remain joined together as they move within/between cells/organisms ex. surface tension

adhesion

water "sticking" to other molecules/substances ex. add water to a graduated cylinder(at the surface the water creeps up slightly on the sides), water sticking to the sides of blood vessels

Surface tension

a force that acts on the particles at the surface of a liquid; tightness across the surface of water; allows insects to walk on water and water beads to form on windows

How does surface tension force the surface of water to curve?

surface tension but downwards

Meniscus

a curved surface

capillary action

upward movement from the force of cohesion and adhesion; explains how water moves against the force of gravity

What causes the tightness across the surface of water?

polar molecules pulling on each other(in liquid water, each water molecule is pulled in all directions by other water molecules); the tightness forms a kind of skin at the water's surface

What causes the molecules at the surface to be held more tightly?

the attractive force from other water molecules pulls only downward and sideways which causes molecules at the surface to be held more tightly

why does ice float on water

Water molecules are spaced farther apart in ice than in liquid water.

specific heat

the amount of heat needed to raise 1kg of a substance 1°; unit is joule per kilogram per degree Celsius

Water is an excellent....

solvent; dissolves anything polar or ionic; does not dissolve nonpolar substances ex. wax and oil (hydrophobic)

nonpolar molecule

covalently bonded; do not have a difference in charge across the molecule; even distribution ex. fats, oil, waxes

What does the ability of water to dissolve substances allow it to do?

deliver essential nutrients to cells in plants, animals, and other organisms; dissolves nutrients in our food

What are molecules that like water called?

hydrophilic

What are molecules that dont like water called?

hydrophobic

Water is less dense as what

a solid; most substances are more dense as a solid than liquids, but opposite for water

Water has a high....

specific heat; takes more energy to raise water's temperature compared to other liquids

Water has a high heat of...

evaporation; takes lots of energy to make water evaporate-used by animals to cool down

What happens to water due to the many attractions among water molecules?

it makes large bodies of water heat up more quickly than nearby land; it leads to warmer air over land than over water on summer days

What percent of the Earth is water?

70%

What percent is our body made up of water?

65%-75%; 82% of our blood is water

Most common atoms in humans:

oxygen, hydrogen, carbon, and nitrogen makes up 99% of our body

Different types of macromolecules

carbohydrates, lipids, protein, and nucleic acids

other names for macromolecules

biomolecules and organic molecules

macro/bio/organic molecules

molecules that exist in all living things; all things are formed from them

Carbohydrates

organic compound that consists of carbon, hydrogen, and oxygen in a 1:2:1 ratio; monomer is monosacharide(sugar); disaccharide(two sugars combined); polymer is polysacharide(multiple sugar); ex. glucose and fructose; foods: potatoes, bread, pasta

What atoms make up carbs?

carbon(C), hydrogen(H), oxygen(O)