The Science of Biology and the Chemistry of Life

Question 1

Science (def)

Answer 1

an organized way of gathering and analyzing evidence about the natural world

Question 2

Goals of science are

Answer 2

• provide natural explanations for events in the natural world
• use explanations to understand patterns in nature and make useful predictions about natural events

Question 3

Scientific methodology involves

Answer 3

• observing and asking question
• making inferences and forming hypotheses
• conducting controlled experiments
• collecting and analyzing data
• drawing conclusions

Question 4

Inference (def)

Answer 4

a logical interpretation based on what scientists already know

Question 5

Hypothesis (def)

Answer 5

a scientific explanation for a set of observations that can be tested in ways that support or reject it

Question 6

Theory (def)

Answer 6

well tested explanation that unifies a broad range of observations and hypotheses, and enables scientist to make accurate predictions about new situations

Question 7

Bias (def)

Answer 7

a particular preference or point of view that is personal, rather than scientific

Question 8

Biology (def)

Answer 8

the study of life

Question 9

Characteristics of living organisms

Answer 9

• made of cells
• based on a universal genetic code
• obtain and use materials and energy
• grow and develop
• reproduce
• respond to their environment
• maintain a stable internal environment
• change over time

Question 10

DNA (def)

Answer 10

• deoxyribonucleic acid

- genetic material that organisms inherit from their parents

Question 11

Stimulus (def)

Answer 11

a signal to which an organism responds

Question 12

Sexual Reproduction (def)

Answer 12

cells from two parents unite to form the first cell of a new organism

Question 13

Asexual Reproduction (def)

Answer 13

a single organism produces offspring identical to itself

Question 14

Homeostasis (def)

Answer 14

relatively constant internal, physical, and chemical conditions that organisms maintain

Question 15

Metabolism (def)

Answer 15

the combination of chemical reactions through which an organism builds up or breaks down materials

Question 16

What three subatomic particles make up atoms?

Answer 16

protons +
neutrons
electrons -

Question 17

Atom (def)

Answer 17

basic unit of matter

Question 18

Nucleus (def)

Answer 18

center of an atom and has a positive charge

Question 19

What are three characteristics of an electron

Answer 19

• negative charge
• 1/1840 the mass of a proton
• in constant motion outside the nucleus

Question 20

What two subatomic particles have similar mass?

Answer 20

• neutron

- proton

Question 21

Element (def)

Answer 21

a pure substance that consists entirely of one type of atom

Question 22

Atomic Number (def)

Answer 22

the number of protons in the nucleus

Question 23

Isotopes (def)

Answer 23

atoms of the same element that differ in the number of neutrons they contain

Question 24

How are all of the isotopes of an element similar?

Answer 24

Because they have the same number of electrons, all isotopes of an element have the same chemical properties

Question 25

In what ways do compounds differ from their component elements?

Answer 25

The physical and chemical properties of a compound are significantly different than those of the elements from which it is formed. (oxygen+hydrogen are gasses and combine to form a liquid)

Question 26

Compound (def)

Answer 26

a substance formed by the chemical combination of two or more elements in definite proportions

Question 27

What are the main types of chemical bonds?

Answer 27

- ionic | - covalent

Question 28

Ionic bond (def)

Answer 28

formed when one or more electrons are transferred from one atom to another

Question 29

Covalent bond (def)

Answer 29

type of bond between atoms in which electrons are shared

Question 30

Molecule (def)

Answer 30

the smallest unit of most compounds

Question 31

When atoms share two electrons, what type of bond is it?

Answer 31

single covalent bond

Question 32

When atoms share four electrons, what type of bond is it?

Answer 32

double covalent bond

Question 33

When atoms share six electrons, what type of bond is it?

Answer 33

triple covalent bond

Question 34

van der Waals forces (def)

Answer 34

slight attraction that develops between oppositely charged regions of nearby molecules

Question 35

How does the structure of water contribute to its unique properties?

Answer 35

Because water is a polar molecule, it is able to form multiple hydrogen bonds, which account for many of water's special properties - cohesion - adhesion - heat capacity

Question 36

A molecule in which the charges are unevenly distributed is said to be _____ because the the molecule is a bit like a magnet.

Answer 36

polar

Question 37

Hydrogen bond (def)

Answer 37

weak attraction between a hydrogen atom and another atom

Question 38

Cohesion (def)

Answer 38

an attraction between molecules of the same substance (pond skimmers)

Question 39

Adhesion (def)

Answer 39

an attraction between molecules of different substances (water in a graduated cylinder forming a meniscus)

Question 40

How does water's polarity influence its properties as a solvent?

Answer 40

Water's polarity gives it the ability to dissolve both ionic compounds and other polar molecules

Question 41

Mixture (def)

Answer 41

a material composed of two or more elements or compounds that are physically mixed together but not chemically combined

Question 42

Solution (def)

Answer 42

type of mixture in which all the components are evenly distributed

Question 43

Solute (def)

Answer 43

substance that is dissolved in a solution

Question 44

Solvent (def)

Answer 44

dissolving substance in a solution

Question 45

Suspension (def)

Answer 45

mixture of water and non dissolved material

Question 46

Why is it important for cells to buffer solutions against rapid changes in pH?

Answer 46

Buffers play an important role in maintaining homeostasis in organisms.

Question 47

pH scale (def)

Answer 47

scale with values from 0 to 14, used to measure the concentration of H+ ions in a solution

Question 48

Acid (def)

Answer 48

compound that forms hydrogen ions (H+) in solution; solution with a pH of less than 7

Question 49

Base (def)

Answer 49

compound that produces hydroxide ion (OH-) in solution; solution with a pH of more than 7

Question 50

Buffer (def)

Answer 50

compound that prevents sharp, sudden changes in pH

Question 51

Ion (def)

Answer 51

atom that has a positive or negative charge

Question 52

A pH of 0 to 7 is considered _____

Answer 52

acidic

Question 53

A pH of 7 to 14 is considered _____

Answer 53

basic

Question 54

A pH of 7 is considered _____

Answer 54

neutral

Question 55

What elements does carbon bond with to make up life's molecules?

Answer 55

carbon can bond with - sulfur - phosphorus - oxygen - nitrogen - hydrogen

Question 56

Why is carbon so special?

Answer 56

carbon atoms have four valence electrons and carbon atoms can bond with each other to form chains

Question 57

Monomers (def)

Answer 57

A small chemical unit that makes up a ploymer

Question 58

Polymers (def)

Answer 58

molecules compose of many monomers; makes up a macro molecule

Question 59

What are the four groups of macro molecules?

Answer 59

- carbohydrates - lipids - nucleic acids - proteins

Question 60

Carbohydrates (def)

Answer 60

compound made up of carbon, hydrogen, and oxygen atoms; type of nutrient that is the major source of energy for the body

Question 61

Monosaccharides (def)

Answer 61

simple sugar molecule

Question 62

Lipids (def)

Answer 62

macro molecules made mostly from carbon and hydrogen atoms; includes fats, oils, and waxes

Question 63

Nucleic acids (def)

Answer 63

macro molecules containing hydrogen, oxygen, nitrogen, carbon, and phosphorous

Question 64

Nucleotides (def)

Answer 64

sub unit of which nucleic acids are composed; made up of a 5-carbon sugar, a phosphate group, and a nitrogenous base

Question 65

Proteins (def)

Answer 65

macro molecule that contains carbon, hydrogen, oxygen, and nitrogen; needed by the body for growth and repair

Question 66

Amino acids (def)

Answer 66

compound with an amino group on one end and a carboxyl group on the other