Biology Quiz 1 (ch. 1-4)

Biology is defined as

the scientific study of life

1 - biosphere

Life on earth, location found, atmosphere

2 - ecosystems

all living things in a particular area: terrestrial…

3 - communities

group of organisms in a specific ecosystem

4 - population

individuals of a species living in a specific area

5 - organisms

individual living things

6 - organs

body part made of tissues with specific function

7 - tissues

group of cells that work together

8 - cells

life’s fundamental unit of structure and function

9 - organelles

functional components of a cell

10 - molecules

chemical structure

correct order of the levels of biological organization from smallest to largest:

a.     cells, organelles, organ system, community, ecosystems

b.     molecules, organism, population, communities, biosphere

c.     molecules, cells, tissues, ecosystems, communities

d.     organelles, cells, population, biosphere, ecosystems

e.     cells, organs, population, ecosystems, communities

e. cells, organs, population, ecosystems, communities

3 domains of life

• archaea: consists of prokaryotic organisms (lacks nucleus) that live in many different environments

• bacteria: consists of prokaryotes (lacks nucleus)

• eukarya: consists of organisms that have cells with true nuclei (includes 4 subgroups: plants, fungi, animals, protists)

inquiry

inquiry is the search for information and explanations of natural phenomena

how we define hypothesis

a hypothesis is a tentative answer to a well- framed scientific question

2 important qualities of a hypothesis

testable and falsifiable

controlled experiment

compares an experimental group with a control group

types of data you can collect

• qualitative data (descriptive data)

• quantitative data (numbers)

deductive vs inductive reasoning

• deductive reasoning uses general premises to make specific predictions (general to specific)

• inductive reasoning states repeating specific observations can lead to important generalizations (specific to general)

experimental group vs control group

• experimental group: group that receives the specific treatment or the variable being tested

• control group: untreated group

dependent vs independent variables

• independent: variable you are testing

• dependent: data you get

Explain what is meant by a scientific theory by giving the three ways your text distinguishes a theory from a hypothesis or mere speculation

A scientific theory is an explanation that is broader in scope than a hypothesis, generates new hypotheses, and is supported by a large body of evidence

how are covalent bonds formed? give an example of a covalent bond

Covalent bonds are formed when two atoms share a pair of valence electrons. An example of a covalent bond is found in H2O, as oxygen shares two valence electrons with both hydrogens

what is the difference between Polar and Non Polar Covalent Bond with examples?

• A non-polar covalent bond is when there is equal sharing of electrons

• A polar covalent bond is when there is unequal sharing of electrons

• An example of a non-polar covalent bond would be the single bond of H2 or the double bond of O2

• An example of a polar covalent bond would be the bonds between the hydrogen and oxygen in H2O

what is an Ionic bond? + example

• an ionic bond is a bond that consists of transferring electrons that results in the atoms gaining charges

• an example of an ionic bond would be a sodium atom giving an electron to a chlorine atom. After the exchange, the sodium ion would become a cation (positively charged) and the chloride ion would become an anion (negatively charged)

cation vs anion

A cation is a positively charged ion, while an anion is a negatively charged ion

what is a Hydrogen Bond?

A hydrogen bond forms when a hydrogen ion covalently bonded to an electronegative atom has a slight positive charge and in result is attracted to another nearby electronegative atom

What is an electronegative element? Find examples, how does this help in forming Hydrogen Bond

An electronegative element is an element that attracts electrons in a covalent bond. Elements with high electro negativity include oxygen, nitrogen, and neon. This helps in forming hydrogen bonds because hydrogen ions that are already attached to an electronegative atom are attracted to other nearby electronegative atoms, which is what forms hydrogen bonds in the first place.

matter is made up of __

elements

compounds

different elements coming together

molecule

elements of the same kind in a group

96% of living matter is made up of these four elements: ___; the remaining 4% are these others: ___

Hydrogen (H), Carbon (C), Nitrogen (N), Oxygen (O); Potassium (K), Calcium (Ca), Phosphorous (P), Sulfur (S)

trace elements

elements required in small amounts

subatomic particles of an element

• neutrons (neutral)

• protons (positive)

• electrons (negative)

an elements atomic number is equal to

the number of protons

the number of protons is equal to

the number of electrons

the mass number is the sum of

protons and neutrons

atomic mass can be approximated by

the mass number

how to find number of neutrons

by subtracting the atomic number from the atomic mass

isotopes

• all atoms of an element have same number of protons but may differ in number of neutrons (so atomic mass varies)

• isotopes are two atoms of an element that differ in number of neutrons

• radioactive isotopes decay spontaneously, giving off particles and energy, and become diff element altogether

the more shells of electrons an atom has, the more ___ they have

energy

covalent bonds

• strong

• the sharing of a pair of valence electrons bony two atoms

• can form between atoms of same or different element(s)

bonding capacity in covalent bonds:

atom’s valence

notation used to represent atoms and bonding is called a ___ formula, or can be further abbreviated with a _____ formula

structural formula (ex: H—H); molecular formula

nonpolar covalent bond vs polar covalent bond

nonpolar: equal sharing of electrons; polar: unequal sharing of electrons (when one atom is more electronegative and the atoms do not share the electrons equally)

unequal sharing of electrons causes a partial positive or negative charge for each atom or molecule

water is called a ___ molecule. why?

polar; because it has polar covalent bonds (O is electronegative and so H has + charge and O has - charge)

partial charge

partial charged occur when an H atom is covalently bonded to a very electronegative atom

H bonds occur between two molecules with ___ charges

partial

electronegativity

an atoms attraction fore the electrons in a covalent bond; the more electronegative an atom, the more strongly it pulls shared electrons toward itself

ionic bonds

• can be weak or strong - depends on environment (typically more weak)

• transfers electrons - does not share

• ex: transfer of an electron from sodium to chlorine

• after the transfer of an electron both atoms have charges - ions

hydrogen bonds

• form when a hydrogen atom covalently bonded to one electronegative atom is also attracted to another electronegative atom

van der waals interactions

• if electrons are distributed asymmetrically in mol/atoms, “hot spots” form of positive and negative charge (congregation in one area increases attraction)

• attractions between mols that are close together as a result of these charges

• interactions can be strong

• seen in proteins

• ex: gecko walking on wall

why is water considered a polar molecule?

because electrons are shared unequally between the oxygen and hydrogen atoms

explain how hydrogen bonding contributes to water’s high specific heat

hydrogen bonding contributes to waters high specific heat because water molecules can move freely when hydrogen bonds beak due to heat being absorbed

cohesion vs adhesion

• cohesion is a phenomenon in which hydrogen bonds hold the molecules within water closely together

• adhesion is the attraction that exists between two diff substances

solvent

dissolves something within a solution (ex: water)

solution

homogenous mixture of substances (liquid)

solute

is what dissolves in a solution

aqueous solution

solution that has water serving as the solvent

hydrophobic vs hydrophilic substances + examples

A hydrophobic substance does not have an affinity for water (does not dissolve in water), while a hydrophilic substance has an affinity for water (will dissolve). An example of a hydrophobic substance would be oils bc they have relatively nonpolar bonds. An example of a hydrophilic substance would be sugar.

4 properties of water that are important for life + how they result from hydrogen bonding

• cohesive behavior (sticks together) results from hydrogen bonding bc hydrogen bonds hold water molecules together - cohesion helps transport of water against gravity in plans

  • surface tension is related to cohesion, and is a measure of how hard it is to break the surface of a liquid. water has an unusually high surface tension due to hydrogen bonding between mol at air-water interface and to the water below

• moderation of temperature results from hydrogen bonding bc water absorbs heat from warmer air and releases stored heat to cooler air, can absorb or release a large amount of heat with only a slight change in own temp, heat transfer: ice it water or water to ice

• waters expansion upon cooling results because hydrogen bonds spread out when water freezes; hydrogen bonds form a pattern called a lattice, which prevents the mols from packing close together - evaporative cooling

• waters versatility as a solvent is because of its polarity, which allows it to form hydrogen bonds easily and helps dissolve many compounds

what is the buffering system that minimizes blood pH changes?

bicarbonates - natural buffers that neutralize acidic substances in blood. When any acidic substance enters the bloodstream, the bicarbonate ions neutralize the hydronium ions forming carbonic acid and water. Carbonic acid is already a component of the buffering system of blood. Thus hydronium ions are removed, preventing the pH of blood from becoming acidic.

how do buffers moderate pH change?

most of them work by minimizing the changes in concentrations of H+ and OH-. most of them have an acid-base pair that reversible combines with H+

the factors that allow water to travel up plants to reach leaves

cohesion and adhesion

specific heat definition

the amount of heat that must be absorbed or lost for 1 g of that substance to change its temp by 1 degree celsius

the specific heat of water is 1 cal/g/degrees C

an acid is any substance that increases the __ concentration of a solution

H+

a base is any substance that reduces the __ concentration of a solution

H+

intermolecular and intramolecular bonds

• The covalent bonds between the hydrogen and oxygen atoms in a water molecule are called intramolecular bonds

• The hydrogen bonds between hydrogen and other oxygen atoms (due to their electronegativity) are called intermolecular bonds

label the isomer

structural isomers

Structural isomers differ in the arrangement of covalent bonding partners, as shown in these two isomers of C§H12.

label the isomer

cis-trans isomers

cis isomer: The two Xs are on the same side

trans isomer: The two Xs are on opposite sides. Cis-trans isomers differ in arrangement about a double bond.

In these diagrams, X represents an atom or group of atoms attached to a double-bonded carbon.

label the isomer

enantiomers

Enantiomers differ in spatial arrangement around an asymmetric carbon, resulting in molecules that are mirror images, like left and right hands. The two isomers here are designated the L and D isomers from the Latin for "left" and "right" (levo and dextro)

Enantiomers cannot be superimposed on each other.

what is a hydrocarbon? name two. are they hydrophobic or hydrophilic?

a hydrocarbon is an organic mol that only consists of carbon and hydrogen

they are hydrophobic

how many valence electrons does carbon have? how many bonds can carbon form? what type of bonds does it form with other elements?

4, 4, covalent bonds

hydroxyl group

—OH (may be written as HO—)

is polar due to electronegative oxygen

forms hydrogen bonds with water, helping dissolve compounds such as sugars

compound name: alcohol (specific name usually ends in -ol)

carbonyl group

sugars with ketone groups are called ketones; those with aldehydes are called aldoses

compound name: ketone (carbonyl group is within carbon skeleton) or aldehyde (carbonyl group is at the end of a carbon skeleton)

carboxyl group

—COOH

acts as an acid (can donate H+) bc the covalent bond between oxygen and hydrogen is so polar

compound name: carboxylic acid, or organic acid

amino group

—NH2

acts as a base; can pick up an H+ from the surrounding solution (water, in living organisms)

compound name: amine

sulfhydryl group

—SH (may be written as HS—)

two —SH groups can react, forming a “cross-link” that helps stabilize protein structure

hair protein cross-links maintain straightness/curling’s of hair

compound name: thiol

phosphate group

—OPO32-

contributes negative charge (1 - when positioned inside a chain of phosphates; 2 - when at the end)

when attacked, confers on a mol the ability to react with water, releasing energy

compound name: organic phosphate

methyl group

—CH3

affects the expression of genes when bonded to DNA or to proteins that bind to DNA

affects shape and function of male and female sex hormones

compound name: methylated compound

—NH2

amino group

can form covalent cross-links that stabilize protein structure

sulfhydryl group

key component of ATP

phosphate group

can affect gene expression

methyl group

—CH3

methyl group

chem group that is always polar

hydroxyl group

determines two groups of sugars

carbonyl group

has acidic properties

carboxyl group

COOH

carboxyl group

acts as base

amino group

electron distribution diagram of carbon

4 ways carbon skeletons can vary

length, branching, double bond position, presence of rings

some carbon chains have double bonds, which can vary in number and location

organic compounds

compounds containing carbon

organic chemistry

the study of organic compounds (compounds containing carbon)

what makes carbon special?

it has the ability to form 4 bonds, meaning it can be used to build an inexhaustible variety of organic mol

different species and different organisms are distinguished by variations in types of org mol they make

the key to an atoms chemical characteristics is ____ ____

electron configuration

determines kinds/#s of bonds an atom forms w/ others

when carbon forms 4 single cov bonds, the bonds angle toward the contents of an imaginary ____; when 2 carbon atoms are joined by a double bond, the bonds from both carbons are in the ___ plane, so atoms joined to those carbons are as well

tetrahedron, same

most frequent bonding partners of carbon

hydrogen, oxygen, nitrogen - 4 main atoms in org mols

function of hydrocarbons

can undergo reactions that release a relatively large amount of energy

the gas that fuels a car consists of hydrocarbons, and the hydrocarbon tails of fats serve as stored fuel for plant embryos (seeds) and animal as

isomers are ___

compounds that have the same numbers of atoms of the same elements but different structures and hence different properties