bio topic 2 : flashcards

molecules of life

mass:

a measure of the amount of material in an object

what are the 3 forms of mass?

1. solid

2. liquid

3. gas

element:

a substance that cannot be broken down into other substances by chemical reactions

all atoms with the same number of ____ in the nucleus are all of the same _____

1. protons

2. element

atomic number:

the number of PROTONS in the nucleus

top number

mass number:

the TOTAL number of PROTONS and NEUTRONS present in the nucleus of an element

bottom number

what are the 4 most abundant and important elements that make up about 96% of the weight?

1. oxygen (O)

2. carbon (C)

3. hydrogen (H)

4. nitrogen (N)

compounds:

elements combined together

atom:

smallest unit of matter

what 3 subatomic particles make up an atom?

1. proton

2. neutron

3. electron

proton:

positively charged (+)

electron:

negatively charged (-)

neutron:

neutral/no charge

what determines the element?

protons

what participates in chemical reactions?

electrons

what determines isotopes?

neutrons

what is an atom when the protons and electrons are equal?

it is neutral

what moves around the nucleus?

electrons

nucleus:

the center core of an atom that contains neutrons and protons

isotope:

atoms of the same element that have different number of neutrons

chemical bonds:

atoms transferring or sharing electrons

what are the three types of chemical bonds:

1. ionic bonds

2. covalent bonds

3. hydrogen bonds

ionic bonds:

• when an atom gains or loses and electron

• always polar; electrically charged

  • distinct positive and negative ions that attract each other

    • table salt

covalent bonds:

• when 2 atoms share electrons

• hold atoms together in a molecule

  • formaldehyde

hydrogen bonds:

polar molecules with an uneven distribution of charge

attraction between a covalently bonded hydrogen atom and another atom taking part in a separate covalent bond.

chemical reactions:

process of breaking down or forming new chemical bonds

reactant:

the starting material

product:

the end material

matter cannot be ____ or ____

1. created

2. destroyed

what are water’s 4 life-supporting properties

1. cohesion

2. ability to moderate temperature

3. ice floats

4. being the universal solvent

cohesion:

the tendency of molecules of the same kind to stick together

what makes water cohesive?

hydrogen bonding

surface tension:

measure of how difficult it is to stretch or break the surface of a liquid

evaporated cooling:

when a substance evaporates and the surface of the liquid remaining behind cools down

solution:

a liquid consisting of a homogenous mixture of 2 or more substances

solvent:

the dissolving agent

solute:

the dissolved substance

water does not mix with ______/_____

oil/fat

acid:

chemical compound that releases H+ to a solution

pH level BELOW 7

water in solid form is _____, ______, and ______

1. less dense

2. further away

3. moves slower

base:

a compound that accepts H+ and removes them from a solution

pH level ABOVE 7

pH scale:

measures the acidity of a solution

each pH unit represents a ______ change in the concentration of H+

tenfold

what is pH 7

neutral

lactose:

the main sugar found in milk

lactose intolerance:

the inability to properly digest lactose

organic compounds:

carbon-based molecules

carbon mostly bonds with what other elements

1. hydrogen

2. oxygen

3. nitrogen

polymer:

made by stringing together many smaller monomers

monomer:

subunit of a polymer

dehydration reaction:

removes a molecule of water to line 2 monomers together

hydrolysis:

adds water to breaks down molecules

digestion is an example of what kind of chemical reaction?

hydrolysis

4 types of macromolecules:

1. carbohydrates

2. lipids

3. proteins

4. nucleic acids

carbohydrates:

sugars and polymers of sugars

primary source of dietary energy

hydrophilic

hydrophilic:

water-loving

monosaccharides:

the simplest carb molecule

glucose:

the universal food

disaccharide:

double sugar from two monosaccharides by dehydration reaction

sucrose:

when glucose and fructose are combined

ex > table sugar

lactose:

combination of galactose and glucose

ex > milk sugar

maltose:

2 glucose linked together

polysaccharides:

3 or more monosaccharides

glycogen:

animal starch

glycose is ______ to _____ when u need energy

1. broken down

2. release glucose

cellulose:

the most abundant organic on Earch

ex > grass , wood

lipids:

fats

hydrophobic: water-resisting

saturated fats:

do not have a double bond

maximum number of hydrogens

ex > butter

unsaturated fats:

have double bond

has fewer than the maximum number of hydrogens

ex > oils

steroids:

lipid with 4 carbon rings and no fatty acid tails

polarity:

Separation of charge into positive and negative regions.

fat:

a triglyceride

cholesterol:

key compenent of a cell membrane

functions of fat:

1. energy storage

2. cushioning

3. insulation

proteins:

polymers of amino acid monomers

account for 50% of the dry weight of most cells

instrumental in almost everything you do

5 function of protein:

1. structural proteins > provide support

2. storage protein > provide amino acids for growth

3. contractile proteins > helps movement

4. transport proteins > help transport substances

5. enzymes > help chemical reactions

how many amino acids make up proteins?

20

what enables the molecule to carry out its specific functions?

the proteins 3D structure

what can a change in the sequence do to a protein:

affect the proteins ability to function

3 attachment groups for amino acids:

1. carbon group

2. amino group

3. hydrogen atom

how do cells link amino acids together?

dehydration reactions

nucleic acids:

macromolecules that store information

polymers made from monomers called nucleotides

polypeptide chains:

long chains of amino acids linked by dehydration reactions

2 types of nucleic acids:

1. RNA

2. DNA

DNA:

genetic material inherited from parents

gene:

discrete unit of inheritance encoded in a specific stretch of DNA that programs the amino acid sequence of a polypeptide

4 nitrogenous bases used to make up DNA

1. adenine(A)

2. thymine (T)

3. guanine (G)

4. cytosine (C)

which nitrogenous bases pair together every time?

A with T

G with C

3 parts that make up each nucleotide:

1. five-carbon sugar

2. phosphate group

3. nitrogen-containing base