biology 1500 exam 1 (chapter 1-4)

Is water polar or non-polar? Why?

polar; it has an unequal sharing of electrons which creates an unequal charge

What is a polar covalent bond?

A covalent bond in which electrons are not shared equally

What is a hydrogen bond?

A weak bond between a hydrogen atom with a partial positive charge and another atom with a partial negative charge

What is electronegativity?

ability of an atom to attract electrons

What would be the effect on the properties of water if oxygen and hydrogen had the same electronegativity?

Water wouldn't be cohesive and wouldn't be able to bond with other water molecules. Other things wouldn't dissolve in water. Water would be a nonpolar molecule.

What are the four emergent properties of water?

cohesive behavior, ability to moderate temperature, expansion upon freezing, versatility as a solvent

What is cohesion?

Ability of water molecules to attract each other via hydrogen bonds

what is adhesion?

Ability of matter to stick to other substances

What is the result of cohesion?

high surface tension

T/F: cohesion doesn't contribute to the transport of nutrients and water in plants

False

How does water moderate air temperature

by absorbing heat from air that is warmer and releasing the stored heat to air that is cooler

Why is water an effective heat bank?

It can absorb/release a large amount of heat with only a slight change in its own temperature.

Kinetic energy

energy of motion

thermal energy

kinetic energy associated with the random movement of atoms or molecules; reflects the total amount of kinetic energy

Temperature

A measure of the average kinetic energy in matter

Does temperature depend on volume?

No. Thermal energy depends on volume

T/F: whenever two objects of different temperatures are brought together, thermal energy passes from cooler to warmer until the same temp.

False. Moves from warmer to colder

Heat

the transfer of thermal energy

Calorie

Amount of heat required to raise the temperature of 1 g of water by 1°C. Conversely, a calorie is also the amount of heat that 1 g of water releases when it cools by 1°C

kilocalorie

Amount of heat needed to raise the temperature of 1 kg of water by 1°C

specific heat

Measure of how well a substance resists changing its temperature when it absorbs or releases heat.

Why does water have a high specific heat?

Much of the added energy is required to break hydrogen bonds.

When water evaporates, what is broken?

Hydrogen bonds

heat of vaporization

the quantity of heat a liquid must absorb for 1 g of it to be converted from the liquid to the gaseous state

T or F: Heat is absorbed when hydrogen bonds break and heat is released when hydrogen bonds form

T

What causes ice to float?

hydrogen bonds make water less dense by making it more ordered

Why is floating ice important?

* otherwise, lakes would freeze solid
* no life would exist in some areas

Solvent

A liquid substance capable of dissolving other substances

Solute

Substance being dissolved

aqueous solution

a solution in which water is the solvent

Why is water a versatile solvent?

due to its polarity, which allows it to form hydrogen bonds easily

hydration shell

When each ion is completed surrounded by a sphere of water molecules

T or F: a compound needs to be ionic to dissolve in wate

F

Hydrophilic

\n water loving

Hydrophobic

Water fearing

hydrogen ion

When a hydrogen atom goes to another molecule and leaves its electron behind

hydroxide ion

A negatively charged ion made of oxygen and hydrogen.

Hydronium ion

hydrogen ion combines with a water molecule to form a hydronium ion, H3O(+)

Buffer

a substance that minimizes changes in pH in a solution

Stanely Miller experiment

* Abiotic synthesis of organic compounds happened near volcanoes
* created a fake system to represent the ocean, atmosphere, and rain water

Stanley Miller experiment results

* A variety of organic molecules was found that were common in organisms and complex molecules like amino acids/hydrocarbons were also found
* molecules found were formaldehyde, hydrogen cyanide, amino acids and hydrocarbons

conclusion of stanley miller's experiment

Organic life may have been synthesize abiotically on early earth

How many valence electrons does carbon have?

4, meaning that it can form 4 bonds

What type of bond does carbon have with other elements?

Covalent bonds

Carbon chains form skeletons of organic molecules. How can the skeletons differ

vary in length and shape

What are the carbon skeletons?

Branched, rings, straight

Hydrocarbons

organic molecules consisting of only carbon and hydrogen

What are the major components of petroleum?

hydrocarbons

T or F: hydrocarbons are hydrophillic

F. They are hydroPHOBIC

do hydrocarbons release a lot of energy?

Yes. (Gasoline is made of hydrocarbons)

Isomer

compounds with the same chemical formula but different structures

isomer vs. isotope

* Isotope: the same element but it has a different amount of neutrons which change the atomic mass
* isomer: compounds that have the same elements present but have a different overall structure which changes the function of the molecule

What are the three types of isomers?

structural, cis-trans, enantiomers

structural isomer

differ in the covalent arrangements of their atoms. a molecule can be a straight chain and the same molecule could be branches

cis-trans isomers

have the same covalent bonds but differ in spatial arrangements around a double bond

Enantiometers

* Isomers that are mirror images of each other
* like your left hand and right hand

What do the distinctive properties of an organic molecule depend on?

Arrangement of carbon skeletons AND the various chemical groups attached to the skeleton

Functional group

Components of carbon skeletons that are most commonly involved in chemical reactions

What are the seven functional groups?

* hydroxyl
* carbonyl
* carbonyl
* amino
* sulfhydral
* phosphate
* methyl

Characteristics of hydroxyl group

* OH
* forms hydrogen bonds with water
* Compound name: Alcohol (Ethanol)
* Hydrophilic
* polar

Characteristics of Carbonyl group

* C=O


* sugars with ketone groups (ketoses) or aldehydes (aldoses)
* compound: ketones or aldehyde
* Hydrophilic
* polar

Characteristics of carboxyl group

* COOH
* acts like an acid
* Carboxylic acid or organic acid
* Hydrophilic
* polar

Characteristics of Amino group

* NH2
* Acts as a base
* Compound:Amine
* Hydrophilic
* (Half of it is an acid, the other side is a base)
* polar

Characteristics of Sulfhydryl group

* SH
* can form a "cross-link" that stabilize protein structures
* compound: Thiol
* HYDROPHOBIC
* polar

Characteristics of Phosphate group

* OPO3 (2-)
* contributes a negative charge
* when attached, gives the molecule the ability to react with water which releases energy
* Hydrophillic
* compound: organic phosphate \\n -polar

Characteristics of Methyl group

* -CH3
* affect the expression of genes
* affects the shape and function of sex hormones
* compound name: methylated compound
* nonpolar

What molecule is this?

* Ketone/Acetone


* Carbonyl group

What molecule is this?

* Propanal (An Aldehyde)
* Carbonyl group

What molecule is this?

* Acetic Acid
* Carboxyl group

What molecule is this?

* Glycine
* Amino Acid

What molecule is this?

* Cysteine (Sulfhydral group)

What molecule is this?

* Glycerol Phosphate
* Phosphate group

What molecule is this?

* 5-Methylcystosine
* Methyl group

Estradiol and testosterone are similar in structure but differ in....??

The chemical groups that attach to the rings of the carbon skeleton

T or F: EVEN if two molecules have the same molecular make up, if they are shaped different, they have the same function.

F. They have different functions. A different shape means a different function.

What characteristics distinguish the living from the nonliving?

* Made up of cells (one or more)
* Needs energy
* Reproduction
* Growth and Development
* Contains DNA, proteins, carbohydrates and lipids
* Able to maintain homeostasis
* Responds to the environment
* Evolutionary adaptation
* Order or Organization

List the levels of life's organizational hierarchy from smallest to largest, starting with atoms and ending with the biosphere.

Atoms (molecules), organelles, cells, tissue, organs, organ system, organism, population, community, ecosystem, biosphere

What are the roles of natural selection and mutations in evolution?

* individuals with inherited or advantageous traits are better suited for the environment and will survive and reproduce.
* Over time, a big portion of those individuals will have advantageous traits.

What are the goals of taxonomy?

The goals of taxonomy are to name species and classify them based on evolutionary relationships.

List and describe the four main groups of eukaryote.

* Plantae-of plants produce their own sugars and food molecules by photosynthesis.
* Fungi- absorb nutrients in dissolved form from surroundings
* Animalia-Animals obtain food by eating and digesting organisms.
* Protists- Protists are organisms that aren't any of the above (Plants, Fungi and Animalia.) \n \n

What are the components of the scientific inquiry?

Making observations, forming hypotheses, experimentation, analysis of data and inductive reasoning.

What is the difference between a hypothesis and a theory?

* Hypothesis- Explanation based on observations, prior knowledge or assumptions, that can lead to a testable prediction.
* Theory- explanation that create new hypotheses but is supported by a large body of evidence. (assumed to be correct until further technology and knowledge proves it to be wrong).

Describe each of the five characteristics of life.

* Cells. (Basic unit of life)
* Obtain and use energy. (A living thing must be able to use energy to do work).
* Reproduction. (A living thing must be able to reproduce and create more of its species).
* Responds to the Environment. (A living thing must responds to the environment that it is in to survive and adapt)
* Adapts and evolves. (Animals are able to respond and change when the environment is changing to ensure better survival )

Matter

Anything that has mass and takes up space

Element

A pure substance made of only one kind of atom

Compound

A substance made up of atoms of two or more different elements joined by chemical bonds

What four elements make up 96% of living matter?

carbon, hydrogen, oxygen, nitrogen

What is the difference between essential elements and trace elements?

* Essential elements are elements that required for an organism to survive and live a healthy life
* Trace elements are only needed in small amounts

Neutron

A subatomic particle that has no charge and that is found in the nucleus of an atom

Proton

A subatomic particle that has a positive charge and that is found in the nucleus of an atom

Electron

A subatomic particle that has a negative charge

atomic number

the number of protons in the nucleus of an atom

atomic mass

mass of protons and neutrons in the element

Isotope

An atom with the same number of protons and a different number of neutrons from other atoms of the same element.

electron shell

An energy level representing the distance of an electron from the nucleus of an atom.

Energy

The ability to do work or cause change

What are radioactive isotopes? Give one medical application that uses them.

* Isotopes that are unstable because they constantly lose subatomic particles (decay) which gives off energy.
* We use radioactive isotopes when it comes to diagnostic tests (CT scans).

What subatomic particle is directly involved in chemical reactions between atoms?

Electrons

What is potential energy?

energy that is stored or position

What are valence electrons?

electrons in the outermost shell