bio kahoots and practice questions exam 1

which statement best describes isotopes?

atoms with the same number of protons, but different neutrons

true or false:

an element consists of one kind of atom

true

which is an example of emergent properties?

sodium chloride (NaCl)

which element has 26 protons?

iron (fe)

which particle determines the identity of an element?

proton

true or false:

atomic number changes when an atom becomes an isotope.

false

Magnesium has an atomic number of 12. How many electrons does a neutral atom of magnesium have?

12

two atoms with the same number of protons but different neutrons are called ________.

isotopes

the sum of protons and neutrons in an atom is called:

mass number

Which statement is FALSE about isotopes?

they are different elements

about how many elements are essential for human life?

25

what are the 4 elements that make up 96% of the weight of most living organisms?

carbon, oxygen, hydrogen, nitrogen

true or false:

same trace elements are required to prevent disease.

true

true or false:

there is only one electron shell.

false

what is something radioactive isotopes are used for?

PET scans

what is the difference between ionic and covalent bonds?

ionic: transfer electrons; covalent: share electrons

true or false:

ionic bonds can be polar or non-polar

false

what makes a covalent bond non-polar?

electrons are shared equally

what makes a covalent bond polar?

electrons are shared unequally

true or false:

an ion is not an atom

false

which property explains water "beading up" on a leaf or on your face after a workout?

cohesion

what does surface tension measure?

how difficult it is to break the suface of a liquid

what does adhesion describe?

the clinging of one substance to another

true or false:

thermal energy is the energy associated with the random movement of atoms and molecules.

true

what does temperature measure?

the intensity of heat

true or false:

water is more dense as a solid than as a liquid

false

When a substance evaporates, the surface of the liquid that remains behind cools down. What is this process called?

evaporative cooling

what allows ice to float on liquid water?

ice molecules are less densely packed than in liquid water

water can exist in what 3 forms?

solid, liquid, gas

what happens when polar or charged solutes are placed in water?

they dissolve as water molecules surround them

true or false:

water's versatility as a solvent results from the polarity of its molecules.

true

what is an aqueous solution?

a solution where water is the solvent

what does a buffer do in a solution?

minimizes changes in pH

true or false:

The pH scale is used to describe how acidic or basic a solution is.

true

true or false:

As a solutions pH increases, it's pH number increases also

false

What is a neutral pH?

7

What is an acidic pH?

1

true or false:

As pH increases, the concentration of hydrogen ions (H⁺) in a solution decreases.

true

true or false:

As pH decreases, the concentration of hydrogen ions (H⁺) in a solution increases.

true

How does the acid formed from CO₂ affect coral reefs?

it disrupts the formation of coral skeletons

true or false:

When carbon dioxide (CO₂) dissolves in water, it reacts with water to form a base.

false

how might a chemical compound in the air harm coral reefs?

through chemistry-- CO2 forms an acid in water

why are carbon atoms considered the "lead players" in the chemistry of life?

they can form four covalent bonds, allowing complex molecules

true or false:

the shape of a molecule usually determines its function in the body.

true

true or false:

Cyclohexane (C6H12) and benzene (C6H6) are isomers.

false

Methamphetamine occurs as two isomers: one is an illegal drug, and the other is a sinus medication. What does this show?

the shape of an isomer can change its function

Which of the following is NOT one of the four main ways carbon skeletons can vary?

ability to dissolve in water

true or false:

The carboxyl group can act as an acid by donating an H+ to a solution.

true

which chemical groups do not contain carbon?

hydroxyl, amino, phosphate

which group contains a carbon atom double-bonded to an oxygen atom?

carbonyl

Which group is often involved in energy transfers, such as in ATP?

phosphate

what is lactose?

the main sugar found in milk

why do some adults lose the ability to digest lactose?

their body stops producing lactase after infancy

________ is the enzyme responsible for breaking down lactose.

lactase

which of the following correctly describes the carboxyl group?

-COOH

true or false: the amino group (-NH₂) contains a nitrogen atom bonded to two hydrogen atoms and can act as a base.

true

____________ is the process of breaking a polymer into monomers by adding water.

hydrolysis

which of the following is essentially the reverse of a dehydration reaction?

hydrolysis

true or false:

both hydrolysis and dehydration reactions require enzymes to help make and break bonds.

true

after digestion, new proteins are built in your body cells from amino acids using:

dehydration reaction

what are the building block of polymers?

monomers

does hydrolysis break or create bonds?

breaks

in dehydration reactions, bonds are _________.

created

the four most common elements in living organisms are:

carbon, nitrogen, hydrogen, oxygen

which of the following is commonly added to table salt to prevent the formation of goiters?

iodine

a radioactive isotope has a nucleus that

decays spontaneously

a chemical bond that results in one or more molecules stripping electrons from the outer shell of another molecule is called a(n) ______________ bond

ionic

an uncharged atom of argon has an atomic number of 18 and an atomic mass of 40. this atom has ___ protons, ___ neutrons, and ___ electrons. (same number of protons and electrons)

ps- you get the atomic mass number by adding protons and neutrons

18; 22; 18

which of the following is an example of a polysaccharide?

starch

lactose intolerance is the inability to properly __________.

digest lactose

what are saturated fats saturated with?

hydrogen

what name is given to the following reaction?

(glucose + glucose → maltose + water)

dehydration reaction

the shape of a protein is determined by:

all of the above (the interaction between R-groups pf a chain of amino acids; hydrogen bonds along the backbone of the polypeptide; the sequence of amino acids)

a ______ is an example of a unicellular organism

paramecium

bacteria cells are prokaryotic; unlike a typical eukaryotic cell, they _______.

lack a nucleus

____ are the major lipids of plasma membranes

phospholipids

which of these pairs of organelles are responsible for energy conversion

mitochondrion and chloroplast

information is transfered from the cell nucleus to ribosomes via the molecule __________.

RNA

explain why fats and steroids, which are structurally very different, are both classified as lipids

they are hydrophobic; made almost entirely out of carbon and hydrogens

why does a denatured protein no longer function normally?

if you change the shape of a protein, it ceases to function the same way and may not function at all

why are R groups important?

they decide the shape of a chain

true or false:

RNA does not form strong enough partnerships to form a double helix

true

molecules that have hydroxyl groups (OH) are called _______

alcohols

why are fats hydrophobic

they are nonpolar, so there is no way for water to interact with it

A protein’s _______ structure is the sequence of amino acids in its polypeptide chain, which can consist of alpha helixes or beta pleated sheets

primary

A protein's ________ structure  is the overall three-dimensional shape of a polypeptide, resulting from interactions among R groups

tertiary

A protein's _______ structure is the coiling or folding of the chain, stabilized by hydrogen bonds.

secondary

Proteins made of more than one polypeptide have ________ structure

quaternary

the 4 most common nucleotides found in DNA are:

adenine, thymine, cystocine, guanine

what holds nucleotides to the same strand?

bond between the sugar and the phosphate (sugar phosphate backbone)

true or false:

DNA can copy itself

true

DNA and RNA are both _______ acids

nucleic

what are the domains of living things?

eukarya, bacteria, archaea

_____ and ____ consist of prokaryotic cells; all other forms of life are placed in domain ________ and have eukaryotic cells 

bacteria and archaea; eukarya

true or false:

the cytoskeleton gives the cell shape and structural support

true

________ endoplasmic reticulum has no ribosomes attached while the ________ endoplasmic reticulum has ribosomes attached

smooth; rough

smooth ER ___________________, while the rough ER ____________, and ribosomes on its surface make membrane and secretory proteins

synthesizes lipids and processes toxins; produces membranes