Biology- Water, Biochemistry, Cells

Question 1

What year was it announced that there was evidence of life on Mars? and who announced it?

Answer 1

1996, Dr. David McKay

Question 2

What are the five things necessary for life?

Answer 2

growth, metabolism, movement, reproduction, and response to stimuli

Question 3

what does it mean to be sterile?

Answer 3

unable to reproduce

Question 4

what is a substance that dissolves in a liquid?

Answer 4

a solute

Question 5

what is the liquid in which another substance is dissolved?

Answer 5

a solvent

Question 6

what are chemical reactions?

Answer 6

changes in the chemical composition of substances

Question 7

chemical reactions involve…

Answer 7

reactants and products

Question 8

what types of atoms are in water?

Answer 8

hydrogen and oxygen

Question 9

the smallest units into which a substance can be broken down, and they’re made of protons, neutrons, and electrons

Answer 9

atoms

Question 10

which subatomic particles make up the nucleus?

Answer 10

protons and neutrons

Question 11

consists of two or more atoms held together by chemical bonds

Answer 11

molecule

Question 12

chemical bonds occur between…

Answer 12

two atoms in a molecule that share electrons

Question 13

to pull electrons

Answer 13

electronegative

Question 14

when shared electrons are closer to one atom than the other, that atom has what kind of charge?

Answer 14

partially negative

Question 15

when shared electrons are farther from one atom than the other, that atom has what kind of charge?

Answer 15

partially positive

Question 16

a molecule where different regions have different charges

Answer 16

polar

Question 17

a type of weak chemical bond that forms between hydrogen and another type of atom and is based on the attraction of partial charges

Answer 17

a hydrogen bonding

Question 18

the tendency of molecules to stick together

Answer 18

cohesion

Question 19

why does salt dissolve in water?

Answer 19

the negative pole of water attracts the positively charged sodium and separates the sodium from the negatively charged chloride

Question 20

a substance that gives H+ ions to a solution

Answer 20

acid

Question 21

a substance that takes H+ ions

Answer 21

base

Question 22

simple chemical substances composed of atoms that can’t be broken down

Answer 22

elements

Question 23

the atomic number of an element is based on its number of…

Answer 23

protons

Question 24

an atom’s mass number is based on…

Answer 24

the sum of protons and neutrons

Question 25

all life on earth is based on the chemistry of which element?

Answer 25

carbon