bio test 1

What are the steps in the scientific method?

-exploration and discovery
-testing ideas
-community analysis and feedback
-benefits and outcomes

Define Theory

A well-substantiated explanation of some aspect of the natural world, based on a body of gives that have been repeatedly confirmed

The earth's crust consist mainly of what elements?

oxygen and silicon

The human body consist mainly of what elements?

oxygen, carbon, and hydrogen

Are viruses made of cells?

no

What is the central dogma?

DNA -\> RNA -\> Protein

When simple compounds are combined into more complex molecules, the entropy inside the cell \__________.

decreases

When energy is released as heat, what happens to the entropy?

the entropy increases

Humans and chimpanzees share \_______% of our DNA.

98.8

What do nodes do?

indicate a common ancestor

What makes a good hypothesis?

a prediction about observations not yet made and can be tested by experiment or further observation

What are the characteristics of life?

-complexity
-ability to change in response to the environment
-ability to reproduce
-capacity to evolve

What two elements make up 99% of matter?

hydrogen and helium

What is the first law of thermodynamics?

energy can neither be created nor destroyed; it can only be transformed from one form to another

What is the second law of thermodynamics?

the degree of disorder in the universe tends to increase

The amount of disorder in a system is the \________ of the system

entropy

Who completed the experiment with rotting meat?

Francesco Redi

What did Francesco Redi's experiment prove?

living things only come from other living things

What was the hypothesis which Louis Pasture tested?

that microorganisms can arise by spontaneous generation

What did Louis Pasture's experiment prove?

that microbes carried on airborne dust particles is necessary for microbial growth

Define plasma membrane

separates the living material within the cell from the nonliving environment around it

What is the main difference between Eukaryotes and Prokaryotes?

prokaryotes do not have a nucleus

What are the two sources by which organisms acquire energy?

sun and chemical compounds

Define metabolism

chemical reactions by which cells convert energy from one form to another and build and breakdown molcules

Define ATP

stored energy in a chemical form

How does a virus spread?

hijacks a cell

Define natural selection

the process whereby organisms better adapt to their environment tend to survive and produce more offspring

Define environmental variation

different environments have an effect on the organism

Define genetic variation

difference in genetic material that is transmitted from parents to offspring

Define ecology

the study of how organisms interact with one another and with their physical environment in nature

Elements are made up of \_______ type(s) of atom(s)

one

Atoms are made up of what?

-protons
-neutrons
-electron

Atoms' nucleus is made of what?

protons and neutrons

What is the charge of protons?

positive

What is the charge of a neutron?

neutral

What is the charge of a electron?

negative

What is an ion?

A charged atom

Loss of an electron is a

cation

Gain of an electron is a

anion

If you lose an electron the atom becomes

positive

If you gain an electron the atom becomes

negative

Mass number

protons + neutrons

The further the electrons are from the nucleus of an atom the \_________ stable they are

less stable

Various energy levels are called

shells

Shells contain

orbitals

Tips for drawing a atom's electrons

-must fill the first shell before beginning the second
-each orbital gets one electron before they get two

The second shell of electrons can hold how many?

8 electrons

Carbon has how many valence electrons?

4

What is unique about the rows of the periodic table?

they have the same number of shells and orbitals

What is unique about the columns of the periodic table?

same number of valence electrons

Atoms are most stable when what?

when their shells are filled

Why is carbon so versatile?

it can form 4 bonds

What are the two shapes carbon is usually found in?

-tetrahedron
-pyramidal
-linear

Why could carbon form a linear bond?

because three carbon could form double bonds

Define isomer

same atoms different arrangements

Function is dependent on

structure

Define covalent bonds

chemical bond that involves the sharing of electron pairs between atoms

What is needed to break a covalent bond?

enzyme

Are non-covalent bonds weak or strong?

weak

What is needed to break non-covalent bonds?

heat

What are types of non-covalent bonds?

-ionic
-hydrogen

What are the categories of covalent bonds?

-polar
-non-polar

Does oxygen share electrons equally?

no

What is the partial charge of oxygen in water

negative

What is the partial charge of hydrogen in water?

positive

Define polar molecule

A molecule that has a positive and negative side.

Define electronegativity

Atom's ability to attract and hold electrons

The bigger difference in electronegativity means the \_________ polar

more

Finding electronegativity

Electronengative atoms will have a \__________ negative charge

partial

Define hydrogen bond

weak "attraction" between electronegative atom and a hydrogen bonded to an electronegative atom

What bond forms between two water molecules?

hydrogen bonds

What bonds holds oxygen and hydrogen together?

covalent bonds

What happens when water freezes?

it becomes less dense

What allows water to resist temperature change?

hydrogen bonds

Why does water not evaporate easily?

high boiling temperature

Water is a \______ solvent.

universal

Why is water a universal solvent?

polarity allows for other polar or fully charged molecules to dissolve in water

What makes water cohesive?

hydrogen bonds together are strong and allows surface tension

Define ionic bond

Formed when electrons are transferred from one atom to another and for ions

Ionic bonds in a biological system are very \_________

weak

Define hydrophobic

does not mix with water

Why does hydrophobic molecules aggregate?

to minimize exposure to polar substances

Define Van der Waals forces

weak attraction between atoms due to electron asymmetries

What is an importance of Van der Waals forces?

hold fatty acid tails together

Is an ionic bond partial or full charge?

full charge

Is an hydrogen bond partial or full charge?

partial

Is an Van der Wall partial or full charge?

partial

The more acidic, the \______ the pH

lower

The more basic, the \______ the pH

higher

pH \= ?

-log[H+]

pH and [H+] are \________ related

inversely

How much is one mole of H+?

6.02x10^23 H+

How do you calculate the difference in H+?

divide the higher H+ by the lower H+

What do you do when you divide exponents?

subtract them

When pH decreases, what color does Phenol red turn?

yellow

What is the equation to make carbonic acid?

CO2 (aqueous) + H2O ↔ H2CO3

Carbonic acid dissociates into

HCO3- and H+

What are the four classes of macromolcules?

-proteins
-nucleic acids
-lipids
-sugars

Proteins are \_________ made up of \___________

-polymers
-monomers