FSU Marks Final Exam BSC2010

What is the atomic nucleus and what is it made up of?

the center of an atom made up of protons and neutrons

Atomic number

the number of protons in the nucleus of an atom

Atomic mass

the number of protons and neutrons

How does the structure of atoms determine their chemical properties?

Subatomic particles make up every atom

Valence electrons

an outer shell electron that is associated with an atom, and that can participate in the formation of a chemical bond if the outer shell is not closed; in a single covalent bond, both atoms in the bond contribute one valence electron in order to form a shared pair.

How do atoms interact with each other to form larger molecules?

They rearrange their electrons to create full outer shells

What type of bond is water and why is it a very polar compound?

covalent bond- oxygen pulls electrons away from the hydrogen, creating - and + poles

What is the definition of an ionic bond and give and example?

The donating/ accepting of electrons by a non metal and metal element (cations + and anions -) : Na+ Cl-

What is the definition of a covalent bond?

The sharing of valence electrons between two non metal elements

Non polar covalent bond

electron is shared equally (similar electronegativity)

Examples of NP covalent bonds

O-O

C-C

C-H

Polar covalent bond

unequal sharing of electrons (partial charges on atoms)

Examples of P covalent bonds

O-H

N-H

O-C

N-C

S-H

S-C

Why is -CH3 non polar?

Because hydrogen and carbon have similar electronegativity

What makes a chemical bond weak?

bonds do not involve the exchange or sharing of electrons

Hydrogen bond

- a weak bond that forms when a hydrogen atom covalently bonded to one electronegative atom is also attracted to another electronegative atom

-attractions between S+ and S-

-transient

-collectively strong

Chemical equilibrium

is reached when the forward and reverse reaction rates are equal. At equilibrium, the relative concentrations of reactants and products do not change

Why do hydrogen bonds form between water atoms?

because the water molecule is a polar molecule which means the opposite ends have opposite charges. The polarity allows water molecules to form hydrogen bonds with each other

What is the importance of hydrogen bonds between water atoms?

water has two polar covalent bonds and their molecules are held together by hydrogen bonds

How are how hydrogen bonds responsible for the resistance to changes in temperature?

the high specific heat

How are hydrogen bonds responsible for the storage and release of heat energy?

-heat is absorbed, break H bonds, requires energy

-heat is released, forms H bonds, releases energy

What happens when an ionic compound is dissolved in water?

each ion is surrounded by a sphere of water molecules called a hydration shell

What molecules are able to dissolve in water?

polar (hydrophilic) molecules

What molecules are unable to dissolve in water?

non- polar (hydrophobic) molecules, ex: oil and hydrocarbons

Molarity

a measurement for concentration of solute molecules

T/F: Concentrations of H+ and OH- are equal in pure water

T

What is the hydrogen atom that leaves its electron behind and is transferred as a proton?

a hydrogen ion (H+)

What is the molecule that lost the proton?

a hydroxide ion (OH-)

Acid

- increases H+ concentration

- pH goes down, <7

- donate H+ in aqueous solutions

Base

- decreases H+ concentration

- pH goes up, >7

- donate OH- or accept H+ in aqueous solutions

What modifies the concentrations of H+ and OH-?

adding acids and bases

[H+][OH-] should add up to get...

10-14

What are hydrocarbons and why do they not dissolve in water?

they are organic molecules with just H-C and are non polar

What are the four major biological macromolecules?

Lipids, carbohydrates, proteins, and nucleic acids

Which are polymers and which are not?

All of them are polymers except lipids

Hydroxyl

- alcohol

- polar

-O-H

Carbonyl

- polar

-C=O

Carboxyl

- acidic

- [H+] goes up

- 1 C, 2 O's

Amino

- basic

- [H+] does down

- 1 N, 3 H's

Sulfhydryl

- thiols

- forms covalent bonds with other SH groups

- polar

-S-H

Phosphate

- energy

- polar

- 1 P, 4 O's ---> PO4 ^2-

Methyl

- does not react with water

- non polar, less polarity

- 1 C, 3 H's

Understand how polymers are built from monomers and how they are broken down

Polymers are built from monomers by combining monomers through dehydration reactions, and they are broken apart by hydrolysis

Dehydration reactions

when two monomers bond together through the loss of a water molecules

Hydrolysis

disconnects monomers, breaks covalent bonds, water is added

Identify a lipid from its structure

hydrophobic because is consisted of hydrocarbons which form NP covalent bonds

What is the structural differences between fatty acids and phospholipids?

Fatty acids are completely hydrophobic while phospholipids have hydrophobic bodies and hydrophilic heads with the phosphates

How is the structure of phospholipids responsible for cellular membranes?

The hydrophilic heads combined with they hydrophobic tails (amphipathic) allow the phospholipids to create a bilayer that is semipermeable

Identify common carbohydrates from their structures

Sugars, often contain carbon, hydrogen, and oxygen

What are some common polysaccharides made specifically of glucose monomers?

glycogen, amylose, etc.

What is the structure of glucose?

- 6 carbon sugar

- all carbons have a hydroxyl group except C5

Protein Structure

- monomers: amino acids

- polymers: polypeptides (a single, linear polymer of amino acids

How are amino acids joined together into polypeptides? A polypeptide (protein) is a polymer of amino acids

they are linked together by peptide bonds

What does the sequence of amino acids determine?

a protein's three-dimensional structure

Proteins

a biologically functional molecule that consists of one or more polypeptides

Amino acid monomers

organic molecules with carboxyl and amino groups. They differ in their properties due to differing side chains called R groups

Identify nucleic acids and nucleotides from their structure

a polymer consisting of many nucleotide monomers

What are the individual parts of the nucleotide monomers that make up DNA and RNA?

- Phosphate groups

- Ribose (or deoxyribose) sugar

- Nitrogenous bases

How are the nucleotide monomers connected together into a DNA or RNA polymer

Phosphodiester bonds in DNA polymers connect the 5' carbon of one nucleotide to the 3' carbon of another nucleotide

How do those connections determine the 3' and 5' ends of a nucleic acid polymer?

- the 5′ end with a phosphate group on the 5′ carbon of the sugar

- the 3′ end with a free hydroxyl group on the 3′ carbon of the sugar

Purines

A, G

What are the nitrogenous base pairs in DNA?

A-T

C-G

Pyrimidines

C, T, U

What are the nitrogenous base pairs in RNA?

A-U

C-G

What are cellular membranes made of?

a phospholipid bilayer, with some transport proteins distributed throughout the membrane

What are the properties of the molecules of a membrane and how do they affect membrane and cellular function?

The phospholipid contains a hydrophilic head and a hydrophobic tail, and two of these phospholipids can line up with their heads facing outwards to create the bilayer

Understand the nature of cellular membranes

fluid mosaic model

What molecules can pass right through a cellular plasma membrane and why?

Small non-charged particles can pass through the membrane because they can fit in the gaps between the phospholipids and they do not have any charge that would cause any disruption while going through the membrane

What molecules can pass through with the help of membrane proteins but without the expenditure of energy and how does this happen?

Larger molecules can pass through the membrane through transport proteins when there is a larger concentration of these molecules outside of the cell. This occurs because of facilitated diffusion, and the cell is trying to reach equilibrium

What molecules require the expenditure of energy to cross the membrane and how does a cell achieve this?

A molecule is likely going against the concentration gradient and takes the cell away from equilibrium. The cell achieves this by converting ATP to energy on the transport protein and this energy is used to transport the molecule through the membrane

Tonicity

total solute concentration of a solution

What are the concepts involved in co-transport?

Co-transport involves using the movement of an ion with its concentration gradient to move another molecule against its concentration gradient in one transport

Isotonic and the direction of osmosis

Have the same tonicity, so no change in the cell since the concentrations are equal

Hypotonic and the direction of osmosis

The concentration of the solute is greater inside of the cell than outside of the cell, the cell will swell and possibly burst

Hypertonic and the direction of osmosis

The concentration of the solute is lower inside of the cell than outside of the cell, the cell will shrivel

How do co- transport concepts apply to both cellular respiration and photosynthesis?

After photosynthesis the sugars produced are carried out of the chlorophyll through a co-transport and are carried into other parts of the cell. During cellular respiration, the sugar is carried into the cell also by co-transport

What are the characteristics of catabolic pathways?

- release energy (exergonic)

- toward equilibrium

- spontaneous

- break down complex molecules into simpler compounds (hydrolysis)

- increase entropy

Free energy

the energy associated with a reaction that is capable of doing work

Know how a change in free energy drives a reaction and how that applies to the storage of potential energy

- During a spontaneous change, free energy decreases and the stability of a system increases (exergonic-energy released)

- Increase of free energy of system and promote instability (endergonic-energy required)

- Exergonic reaction provide the energy for the endergonic one

What are the characteristics of anabolic pathways?

- consume energy (endergonic)

- away from equilibrium

- non spontaneous

- build complex molecules from simpler compounds (dehydration)

- decrease entropy

Understand the concept of coupling an exergonic reaction to an endergonic reaction in order to drive the endergonic reaction that otherwise would not take place

-A cell has to do chemical, transport, and mechanical work but in order to do that cells manage energy resources by energy coupling

-ATP powers cellular work by coupling exergonic reactions to endergonic reactions

-Coupled reactions:

Glutamic acid + ammonia = glutamine (endergonic)

ATP= ADP + P (exergonic)

-ATP cycle is a revolving door through which energy passes during its transfer from catabolic to anabolic pathways

If the free work associated with a reaction is negative, then the reaction is ________________, which means it is not driven by an outside force

spontaneous

Entropy

a measurement of randomness or uncertainty

If a reaction is spontaneous, free energy and entropy ___________.

decrease

Enzymes catalyze reactions by __________ energy barriers (they do not provide any energy)

lowering

Do enzymes have an effect on delta g?

no

Enzymes __________ activation energy for a specific reaction

lower

What does it mean for a molecule to be oxidized

loss of electrons, exergonic

What does it mean for a molecule to be reduced

gain of electrons, endergonic

Why are the two reactions always coupled with each other

cannot have one without the other

What are the four parts of cellular respiration?

- Glycolysis

- Oxidation of Pyruvate

- Citric Acid Cycle

- Oxidative Phosphorylation

Glycolysis

- occurs in the cytoplasm

- put in glucose, get 2 molecules of pyruvate

- releases energy and pyruvic acid

Oxidation of pyruvate

- occurs in the mitochondrial matrix

- put in pyruvate, get Acetyl CoA

Citric Acid Cycle

- occurs in the mitochondrial matrix

- put in Acetyl CoA, get 2 ATP and 4 CO2

Oxidative Phosphorylation

- put in electrons, get ATP

- the production of ATP using energy derived from the redox reactions of an electron transport chain; the third major stage of cellular respiration.

Electron Transport Chain

a series of transmembrane protein complexes that shuttle electrons during the redox reactions that release energy used to make ATP

Chemiosmosis

A process for synthesizing ATP using the energy of an electrochemical gradient and the ATP synthase enzyme

Be able to follow potential energy as it is passed from a glucose molecule to ATP molecules

Glucose -> NADH + FADH2 -> Electron Transport Chain -> Proton Motive Force -> ATP

Be able to follow electrons as they are passed from glucose molecules eventually to oxygen

Glucose -> NADH and FADH2 -> Electron Transport Chain -> Proton Motive Force -> O2