Bio Final Exam

The atomic number of an element is the same as the number __ in each atom

Protons

Electrons around atoms spend their time in distinct locations called

Orbitals

If a phosphorus and a hydrogen were in a covalent bond would be

non polar

Atoms on the left side of the periodic table tend to

lose electrons have positive charge

Sulfer would need how many additional electrons to fill its outer electron shell

2

Why would water be described as a polar molecule

Oxygen is more electronegative than hydrogen, leading to an unequal sharing of electron density

What is something not true of water

Water cannot act as a solvent for any organic molecules

Any buffered solution keeps the pH stable by

A weak acid base accepting protons if addition free protons are added, and a weak acid contributing protons if any free protons are removed

Vinegar has a pH of about 3 while coffee has a pH of 5, how many times more protons does vinegar have than coffee

100 times

Hydrogen bonds are between

hydrogens and electronegative molecules in polar covalent bonds

Covalent bonds are polar based on

The electronegative of the elements involved

What is not characterized by hydrogen bonds

salt crystals

What are ionic bonds

formed when atoms transfer electrons from one to another, resulting in oppositely charged ions that attract each other.

Covalent bonds are formed when

electrons are shared by two elements

a mixture where a substance will settle out over time is

suspension

What pH has the lowest concentration of hydrogen ions

A pH of 0

What pH has the highest concentration of hydrogen ions

A pH of 14

The pH of water is 7 because

Water is a weak acid

Whether a compound is a strong or weak acid is based on

the extent to which the compound releases protons in water

In condensation reactions, the atoms that make up a water molecule are derived from

both reactants

What polysaccharide is not branched

Cellulose

What carbon is relevant when deciding if a sugar is an alpha or beta isomer

carbon 1

Sucrose is a disaccharide of which two sugars

Glucose and fructose

What are hexose

monosaccharides with six carbon atoms, including glucose and fructose

Phospholipids can combine to form tiny spherical shapes in water, known as

micelles

In animal cells, glucose is polymerized into which polysaccharide

Glycogen

Polysaccharides are broken down into their respective monomers by what reaction

Hydrolysis

Glycogen contains more branch points in order to

exclude more water molecules

Humans are unable to absorb calories from fiber (cellulose) because

Small intestines don’t contain the enzyme for breaking beta 1-4 glycosidic bonds

A poly-unsaturated fatty acid is

A lipid at room temp

Animals store their energy primarily in what form

triglycerides

The branch points in glycogen and starch are through what type of glycosidic bond

Alpha 1-6

Choline is not essential for

phospholipids

A “standar fatty acid” is one that contains as many __ as possible

hydrogens

Steroid hormones are derived from which precursor molecule

cholesterol

Amino acids are classified by

Characteristics of their side chains or “R” groups

What type of bond is between carbon and nitrogen

peptide bond

Tertiary shape

3-dimensional shape of poly peptide chain

Secondary shape

Hydrogen bonding within the peptide backbone

Quaternary shape

Assembly of multiple subunits into functional proteins

Primary shape

Linear sequence of amino acids

When a protein loses its secondary and tertiary structure it is said to be

denatured

Protein alpha helices and beta sheets are help together by

hydrogen bonds

The amino acid side chains in an alpha helix point in what orientation

away from the center of the helix

What is on amino end of a polypeptide chain

nitrogen

A protein in its biologically active shape is in its __ conformation

Native

Microfilaments are involved in

cell division and cell movement

Microtubules are made of

Tubulin heterodimers

Microtubules are the largest

Cytoskeleton filaments

Are microtubules involved in cell divions

Yes

In what way are intermediate filaments intermediate

in width

A prokaryote lacks which cellular structure

nucleus and endoplasmic reticulum

Does the mitochondrial genome contain all teh proteins necessary for mitochondrial function?

no, it requires proteins encoded by nuclear DNA.

The organelles in plants and algae that carry out photosynthesis are called

Chloroplasts

Photosynthetic organelles have three membranes

outer, inner, thylakoid

What gives the rough endoplasmic reticulum its rough appearance

Ribosomes

What is the main function of the Golgi apparatus

Modify proteins to their final functional state

What can lysosomes digest

various biomolecules, including proteins, lipids, enzymes, and carbohydrates.

Why can microfilaments and microtubules be quickly disassembled

They are made of protein subunits that can be rapidly added or removed, and are soluble

What re-orients the phospholipids from one side of the cell to the other

Flippase

What do cholesterol molecules do in the membrane

make membrane more firm

Membrane proteins can’t

Maintain cells shape

Cells modify which part of the cytoskeleton to undergo phagocytosis

Actin microfilaments

What is apoptosis

cell suicide or programmed cell death

What does the fluid mosaic model say about phospholipids

phospholipids on each side of the membrane can move freely around each other

What is a general function of all cellular membranes

regulate which materials can cross the membrane

What is the primary role of gap junctions between two cells

to coordinate the two cells

What happens when vesicles from the Golgi apparatus delivers their contents to the exterior of the cell

Exocytosis, where materials are released outside the cell.

Does the size of a cell increase when vesicles are taken to the exterior of the cell

no because the membrane is continually being lost from the plasma membrane by endocytosis

What is osmosis

water from low concentration of dissolved material to a region of high concentration of dissolved material

What happens in facilitated diffusion

Cells manipulate channel by hiding molecules to gain more molecules

Where do specialized channel proteins called connexions occur

gap junctions

What is produced in glycolysis

4 ATP, 2 NADH + 2H+, and 2 pyruvate

Are almost all metabolic pathways anabolic

no many are catabolic

What does kinase do

enzyme that adds a phosphate to a molecule

In a chemical reaction in which reactants and products have almost the same free energies what happens to delta G

delta G is close to zero

If the delta G of a chemical reaction is negative and the change in entropy is positive what can you conclude

the reaction is exergonic

Are most enzymes much smaller than their substrates

No, many enzymes are larger

What is enthalpy

the total energy in a system

What is entropy

the amount of disorder in a system

Where is energy stored when ADP gains a phosphate to form ATP

in the high-energy phosphate bonds of ATP

What does a catalyst effect

the amount of activation energy required

When a molecule loses H atoms what has happened

oxidized, loses electrons

What do hydrolase enzymes do

decrease the activation of hydrolysis reactions by inducing strain in the bond to be broken

In yeast the final products of fermentation are

ethanol and carbon dioxide

In humans muscle cells fermentation produces

lactic acid

Glycolysis happens where in the cell

cytosol

Fermentation happens under what conditions

low oxygen levels

Fermentation solves which problems

lack of NAD+ and buildup of pyruvate

The glucose transporter is powered by high concentration of sodium ions, this is an example of

secondary active transport

If a molecule has been reduced it has

gained electrons

Pyruvate oxidation yields which products

Acetyl-CoA, NADH, and CO2

Citric acid cycle takes place

Mitochondria inner most compartment

Can the citric acid cycle be used to store sugars

No, it primarily breaks down acetyl-CoA for energy

Claudine and occlusions are transmembrane proteins are found where

cell adhesion, tight junctions

If an extracellular NAD+ molecule was transported into the innermost mitochondrial compartment, how many lipid bilayers would it have to cross

three

the A in NAD+, FAD and ATP stands for

adenine

Sona means

body

An asymmetric mitotic cell division is when

the two daughter cells are different cell types with different functions

what are germ cells

cells set aside from the somatic cells early in development