Biochemistry Chapter 2-AP Bio

Question 0

Elements

Answer 0

Makes up matter, a substance that cannot be broken down to other substances by chemical reactions.

Question 1

Matter

Answer 1

Anything that takes up space and has mass

Question 2

Compound

Answer 2

A substance consisting of 2 or more different elements combined in a fixed ratio.

Question 3

Essential Elements

Answer 3

Needed by an organism to live a healthy life and reproduce. Humans need 25 elements, plants need 17.

Question 4

Which elements make up 96% of human matter

Answer 4

Carbon
Hydrogen
Oxygen
Nitrogen

Question 5

Trace Elements

Answer 5

Elements required by an organism in minute quantities. Some (iron) are needed by all forms of life, others are required by only certain species.

Question 6

Elements in the human body

Answer 6

Carbon 
Hydrogen
Oxygen
Nitrogen
Phosphorus
Sulfur
Calcium
Magnesium
Sodium
Chlorine
Potassium

Question 7

Atom

Answer 7

The smallest unit of matter so that it still retains the properties of an element.

Question 8

Atomic Nucleus

Answer 8

The dense core of the center of the atoms, protons and neutrons.

Question 9

Which subatomic particles are almost identical in mass

Answer 9

Protons and neutrons

Question 10

Dalton

Answer 10

Unit of measurement for atoms and subatomic particles. =amu

Question 11

John Dalton

Answer 11

British scientist who helped develop atomic theory around 1800.

Question 12

Atomic Number

Answer 12

Number of protons in an atom, written as a subscript to the left of the symbol for the element.

Question 13

Balanced charge

Answer 13

of protons=# of electrons

Question 14

Mass number

Answer 14

The sum of protons plus neutrons in the nucleus of the atom.

Question 15

How is the number of neutrons formed

Answer 15

Subtract the number of protons from the atomic number.

Question 16

What is the simplest atom

Answer 16

Hydrogen. No neurons, single proton and single electron.

Question 17

Atomic mass

Answer 17

Total mass of the atom. Approximately the mass number.

Question 18

Isotopes

Answer 18

Different atomic forms of the same element.

Question 19

How does an element occur in nature

Answer 19

As a mixture of the elements

Question 20

The process of tending to lose subatomic particles

Answer 20

Decay

Question 21

Radioactive isotope

Answer 21

The nucleus decays spontaneously, giving off particles and energy.

Question 22

What does radioactive decay lead to

Answer 22

A change in the number of protons, transforming the atom to an atom of a different element.

Question 23

How are radioactive isotopes used in medical science

Answer 23

Radioactive isotopes are incorporated into biologically active molecules which are used as tracers to track atoms during metabolism, the chemical processes of an organism.

Question 24

Half life of isotope

Answer 24

The time it takes for 50% of the parent isotope to decay. Not affected by temperature, pressure, or any other environmental variable.

Question 25

Radiometric dating

Answer 25

Scientists measure the ratio of different isotopes and calculate hoe many half lives (in years) have passed since an organism was fossilized or a rock was formed.

Question 26

Atoms are mostly __________

Answer 26

Empty space

Question 27

What part of the atom are involved in chemical reactions

Answer 27

Electrons

Question 28

Energy

Answer 28

The capacity to cause change by doing work.

Question 29

Potential Energy

Answer 29

The energy that matter possesses because of its location or structure.

Question 30

The more distant an electron is from the nucleus ________________

Answer 30

The greater its potential energy.

Question 31

How can changes of potential energy of electrons occur

Answer 31

In steps of fixed amounts

Question 32

Electron shells

Answer 32

Characteristic average distance and energy level. Represented by concentric circles.

Question 33

How much potential energy do the shells have

Answer 33

The first shell has the lowest potential energy, the second shell electrons have more energy, the third shell has even more energy.

Question 34

How do electrons move within shells

Answer 34

By absorbing or losing an amount of energy equal to the difference in potential energy between its position in the old shell and that in the new shell. When absorbing energy, electrons move farther out.