Biology Chapter 2

Front 1

Living things have five functional traits in common:

Back 1

- Growth
- Reproduction
- Homeostasis
- Sense and respond to stimuli
- Obtain and use energy

Front 2

Growth:

Back 2

for unicellular organisms, this is an increase in cell size prior to reproduction; for multicellular organisms, this is an increase in an organism’s size as the number of cells making up the organism increases.

Front 3

Reproduction:

Back 3

the process of producing new organisms.

Front 4

Homeostasis:

Back 4

the maintenance of a relatively constant internal environment, even when
the external environment changes.

Front 5

Sense and response to stimuli:

Back 5

organisms respond to stimuli in many ways – they may
move toward a food source or away from a threatening predator.

Front 6

Ability to obtain and use energy:

Back 6

all living organisms require an input of energy to power
their activities, and chemical reactions convert that energy into usable forms
(metabolism). Organisms obtain energy from food.

Front 7

Energy

Back 7

is the ability to do work. Living organisms obtain energy from food, which they either make from sunlight (producer)or consume from the environment (consumer).

Front 8

Metabolism

Back 8

is the sum total of all of the chemical reactions taking place in the cells of a living organism that allow it to obtain and use energy.

Front 9

At its most basic level, all life is composed of

Back 9

chemicals

Front 10

matter

Back 10

is anything that takes up space and has mass.

Front 11

elements

Back 11

All matter on Earth is made up of these

chemically pure substances that cannot be chemically broken down.

Front 12

atoms

Back 12

are what elements exist as

the smallest units of an element that cannot be chemically broken down into smaller units.

Front 13

Atoms have distinct chemical properties determined by the

Back 13

number of subatomic particles the atom has.

Front 14

The subatomic particles of the atoms are

Back 14

protons, neutrons, and electrons

Front 15

protons

Back 15

positively charged particles in the nucleus

Front 16

neutrons

Back 16

uncharged particles in the nucleus

Front 17

electrons

Back 17

negatively charged particles with small mass that orbit around the nucleus in distinct energy shell

Front 18

Nucleus

Back 18

the dense core of an atom

Front 19

Atomic number:

Back 19

It is the number of protons found in nucleus.
- In the periodic table of elements, each element is placed in order by its atomic number.

Front 20

Atomic mass

Back 20

It is the total number of protons and neutrons in the nucleus.

Front 21

Carbon

Back 21

is the fourth most common element in the universe

and the second most common element in your body.

is a key component of the molecules of living organisms because it can form multiple covalent bonds.

Front 22

what six elements make up the bulk of you:

Back 22

Oxygen (65%)
Carbon (18.5%)
Hydrogen (9.5%)
Nitrogen (3.3%)
Phosphorus and sulfur (2%)

Front 23

Covalent bonds are

Back 23

strong chemical bonds resulting from the sharing of a pair of electrons between two atoms.

Front 24

Molecules are formed

Back 24

when atoms link by covalent bonds.

chain of atoms linked by covalent bonds.

Front 25

Organic molecules

Back 25

have carbon-based backbones and at least one C-H bond (e.g., glucose).

Front 26

Inorganic molecules

Back 26

lack carbon-based backbones and C-H bonds (e.g. CO2).

Front 27

Four types of complex organic molecules that make up living things on earth:

Back 27

Carbohydrates
Proteins
Lipids
Nucleic acids

Front 28

macromolecules

Back 28

Carbohydrates, proteins, and nucleic acids

large organic molecules that make up living organisms.

are composed of monomers that are linked together to form a polymer.

Front 29

Monomer

Back 29

is one chemical subunit of a polymer.

Front 30

Polymer

Back 30

is a molecule made up of monomers linked together in a chain.

Front 31

Carbohydrates and functions

Back 31

are organic molecules (polymers) made up of glucose or simple sugar (monosaccharide) subunits (monomers).

Carbohydrates functions:
- energy-storing molecules in organism
- provide structural support for cell

Front 32

Proteins and functions

Back 32

are organic molecules (polymers) made up of amino acid subunits.

- speed up the rate of chemical reaction in living organism
- move things through, around, and inside the cells, and even move the entire cells

Front 33

Lipids and functions

Back 33

(Fat) are organic molecules that generally are hydrophobic (water-fearing)– they don’t mix with water. They are not made of repeating subunits.

- insulation, fats store large amount of energy (Triglycerides)
- some are hormones (sterols)
- important component of cell membrane (phospholipids)

Front 34

Nucleic acids (DNA and RNA)

Back 34

are polymers of repeating subunits of nucleotides.

critical for storage, transmission, and execution of genetic information

Front 35

Cells

Back 35

are the basic structural units of all living organisms.

Front 36

Cells are bounded by a

Back 36

a cell membrane – a double layer (bilayer) of phospholipids that forms the boundary of a cell, separating the contents of a cell from its environment.

Front 37

phospholipid bilayer

Back 37

forms a semi-permeable barrier to substances on either side of it. Water-hating tails (hydrophobic) meet between water-loving heads (hydrophilic).

Front 38

What happens when phospholipids are put into water? And how they arrange themselves in cell membrane to separate the inside and outside environment of a cell?

Back 38

Phospholipids arrange themselves in a bilayer with the hydrophobic (water-fearing) tails on the inside that act as a barrier to water to prevent water from moving into or out of the cell, and the hydrophilic (water-loving) heads arrange themselves on the outside next to water.

Front 39

Properties of water

Back 39

All of life’s chemical reactions take place in water, and many living things can survive only a few days without it.

Water is a universal solvent (a substance in which other substances can dissolve), it transports all of life’s dissolved molecules (solutes) from place to place.

Front 40

Solution:

Back 40

A mixture of solutes dissolved in a water, e.g., salt dissolved in water.

Front 41

Water is a polar molecule

Back 41

a molecule in which electrons are not shared equally between atoms, causing a partial negative charge at one end and a partial positive charge at the other.

Front 42

Ionic bonds:

Back 42

strong bonds formed between oppositely charged ions.

Front 43

ions

Back 43

an atom that has an electrical charge resulting from the loss or gain of electrons.

Front 44

hydrogen bonds,

Back 44

Each water molecule has a partial charge on each end, so it can form electrostatic attractions, known as hydrogen bonds, with one another and with other molecules.

Front 45

Water molecules can absorb a lot of energy

Back 45

before they get hot and vaporize (turn into a gas) because of their hydrogen bonds.

Front 46

Ice floats because

Back 46

it is less dense as a solid than as a fluid.

Front 47

PH:

Back 47

the concentration of hydrogen ions (H+) in a solution.

Front 48

pH ranges from

Back 48

0-14

Front 49

acids PH is

Back 49

<7

Front 50

Basics PH is

Back 50

>7

Front 51

viruses

Back 51

The viruses seem alive because they can reproduce themselves; however, they are not made of cells. They contain genetic material and can make copies of themselves or reproduce by using a living host cell. Viruses use the host cell’s energy mechanism and they lack any of their own.

Front 52

are viruses alive then?

Back 52

no, because a living cell does cell division or reproduction, metabolism, etc., on its own, but a virus does not have these characteristics of a living cell.