Biology 201-Exam 1-Uwe Pott-UWGB

Which of the following statements about exergonic reactions is FALSE?

a) they release free energy (delta G

c) their products have more energy than the reactants

list the characteristic properties of life

-organization

-energy use, metabolism

-homeostasis (internal consistency)

-sensing and responding to stimuli

-movements

-reproduction, development, growth

-evolution

list the biological organization from least to most complex

-atoms

-molecule

-macromolecule

-organelle

-cell

-tissue

-organ

-organ system

-organism

-population

-community

-ecosystem

-biosphere

explain emergent properties and give an example

endothelial cells form a sheet of endothelial cells which leads to a blood vessel

differentiate between the cycling of matter in and the one-way flow of energy through the living world

-the sun provides energy for: producers, consumers, decomposers, and the environment

-producers provide energy for: consumers, decomposers, and the environment

-consumers provide energy for: decomposers and the environment

-decomposers provide energy for: the environment

give examples for the unity of life

-chemical compounds

-reaction mechanisms

-organelles

-cells

-organisms

give examples for the diversity of life

Differences between cells and organisms; kinda relates to organization

Which of the following levels of biological organization are arranged from least to most complex?

molecule, organelle, cell, population

Nucleotides are the building blocks of polynucleotides, also known as nucleic acids. A nucleotide by itself does not carry information, but when nucleotides are joined to form DNA, that macromolecule makes up the genetic information of organisms. This type of phenomenon is an illustration of...

emergent properties

The cell theory states that...

all organisms are composed of cells

Which of the following cell features can be found in bacterial AND plant cells?

Cell membrane and ribosomes

A cell has the following molecules and structures: proteins, DNA, ribosomes, cell membrane, and mitochondria. It could be a cell from...

a plant or an animal

Microtubules...

are involved in the movement of organelles inside the cell

What is the operational sequence of organelles a secreted protein will follow on its way to the cell's surface?

ribosome > ER > transport vesicle > Golgi > transport vesicle > plasma membrane

Describe the size range of biological structures

prokaryotes are about 1-10 micrometers

eukaryotes are about 10-100 micrometers

List features all cells have in common and distinguish between prokaryotic and eukaryotic cells

-all cells have plasma membrane, selective barrier, DNA containing region, cytoplasm, and cytosol

-prokaryotes do not have a cell nucleus

eukaryotes do

List organelles shared by all eukaryotic cells and those unique to plants

-all eukaryotes have a nucleus, cytomembrane (ER, golgi bodies, vesicles, mitochondria)

-only plant cells have plastids (chloroplasts, and amyloplasts), a central vacuole, and a cell wall

Summarize the features and function of the nucleus, nucleolus, nuclear envelope, ribosome, cytomembrane system, mitochondrion, and chloroplasts

Nucleus- where DNA is stored in the cell

Nucleolus- production site of ribosomes (nucleus within the nucleus)

Nuclear envelope- double membrane made up of two lipid bilayers

Ribosomes- translate mRNA to proteins

Cytomembrane system- production of lipids and modification of proteins

Mitochondrion- where ATP is produced

Chloroplasts- organelles of photosynthesis

Explain the endosymbiont theory and list evidence that supports it

mitochondria and chloroplasts are derived from free-living heterotrophic and photoautotrophic bacteria

Evidence:

-contain DNA

-contain ribosomes

-divide

-are surrounded by double membrane

-but can't live independently of the cell

Describe the elements of the cytoskeleton and their interactions with specific motor proteins

supports the cell shape

-microtubules (cell movements; flagella, cilia, spindle fibers)

-microfilaments (cell movements; muscle contraction)

-intermediate filaments (structural support)

List the components of a typical bio-memebrane

lipid bilayer and proteins

Describe the fluid mosaic model for a membrane structure and the evidence for it

interactions between hydrophobic lipid tails are weak; heads don't like the fat in the middle; lipid bilayer behaves as "two-dimensional liquid"

Explain the function of the different types of membrane proteins

Transport proteins- transport molecules that can't go through the bilayer

Receptor proteins- cell signaling

Recognition proteins- "passport" identification tag of a cell for other cells

Adhesion proteins- binding cell

Enzymes- helps biochemical reactions to happen

Define the process of diffusion and list parameters that affect its efficiency

movement of molecules from an area of high concentration to an area of low concentration

-the steepness of the gradient

-size and shape of molecules

-temperature

-distance

Explain the different forms of transport of material across the cell membrane

-Simple diffusion - helps fats and small nonpolar molecules

-Facilitated diffusion - passive transport, aided by a channel or carrier proteins

-Active Transport - uses ATP to go against the concentration gradient

-Bulk Transport - exocytosis and endocytosis

Explain the diffusion of water across the cell membrane (osmosis) and distinguish between hypotonic, hypertonic, and isotonic conditions

osmosis diffuses the water to go through the semipermeable membrane

hypotonic- water goes into cell and the cell bursts if there's no cell wall

isotonic- amount of water going in is the same as the amount of water coming out

hypertonic- water leaves the cell causing it to shrink and shrivel

Describe the consequences of bathing plant or animal cells in hypotonic or hypertonic solutions

Plant cells in a hypotonic solution will not burst because of the cell wall. In hypertonic solutions the cytoplasm will retract but not the cell wall.

Animal cells in a hypotonic solution will swell and burst. In hypertonic solutions, the entire cell will shrink

Distinguish between metabolism, catabolism, anabolism, and different kinds of metabolic pathways

Metabolism- sum of all biochemical reactions in an organism

Catabolism- reactions that PROVIDE energy

Anabolism- reactions that CONSUME energy

Define the change of Gibbs Free Energy, list the two components it is made up of, and explain how it relates to exergonic and endergonic reactions

Gibbs free energy: determines spontaneity of a biochemical reaction

*exergonic reaction- is negative

*endergonic reaction- is positive;

made up of entropy and enthalpy

Define activation energy, explain redox reactions and reversible reactions, and differentiate between open and closed systems

-Activation energy: the energy used to start the reaction

-Redox reactions: reactions that transfer lots of energy

-Reversible reactions: reactions that can go from left to right and right to left

-Open system: take in food and excrete waste

-Closed system: will reach equilibruim

Describe what enzymes are, how they speed up biochemical reactions, and how they achieve substrate and reaction specifically

bio-catalysts or proteins that make reactions happen more efficiently: highly selective about substrates and reactions because the cell has to be controlled and one enzyme can only do one kind of reaction

Explain by which mechanisms enzymes may lower the activation energy of biochemical reactions

Bring substances together, orientation of the substances into favorable positions, if water doesn't come out it becomes nonpolar and lower activation energy

List parameters that can change enzyme activity

-covalent modification

-allosteric regulation

Distinguish between competitive and noncompetitive inhibition of enzymes

-Competitive inhibition= a competitive inhibitor blocks the substrate

-Noncompetitive inhibition= a noncompetitive inhibitor binds outside the active site so a substrate can't bind

Differentiate between the terms cofactor, coenzyme, and co-substrate, and give examples of each

-Cofactor= metal ions (Fe, Mg, Cu)

-Coenzyme= organic compounds, permanetly assiociated

-Co-substrate= temporarily associated, NAD+

Name major elements and certain trace elements that occur in living things

oxygen, carbon, hydrogen, nitrogen... trace elements: iron and iodine

Define the terms element, atom, compound, molecule, ion

Element- the simplest form of something; a pure chemical substance

Atom- the smallest piece of an element

Compound- a substance of two or more equal amounts of different atoms combine

Molecule- where atoms are joined by covalent bonds

Ion- an ionic compound

Describe subatomic particles in the nucleus and the shell of an atom

Protons and neutrons are in the nucleus (protons are positively charged, neutrons are neutral)

Electrons are in the shells of an atom (negatively charged)

Distinguish between the atomic number and the atomic weight of an element

Atomic number is the number of protons

Atomic weight is the number of protons and neutrons added together

Give examples for the use of isotopes in the life sciences and medicine

Radiocarbon dating (we can figure out how old something like a bone or fossil is by using this method)

Radioiodine imaging (we can figure out if something like thyroids are enlarged or cancerous)

Differentiate between polar and nonpolar covalent bonds, ionic bonds, and hydrogen bonds

*Polar covalent bonds have different electronegativity

*Nonpolar covalent bonds have the same electronegativity (covalent bonds are non metals and non metals)

*Ionic bonds transfer electrons (metal and nonmetal)

*Hydrogen bonds are an interaction between hydrogen atoms with a partial positive charge and an electronegative atom with a partial negative charge

Explain how the shape of molecules impact their interactions

s and p orbitals (spheres only have one or two electrons; there are 3 dumbbells in the 2p orbital and each on can hold one or two electrons)

Describe the structure of water molecules and explain their polarity

Two hydrogen atoms and one oxygen atom with polar covalent bonds

Distinguish between substances that can dissolve in water and those which cannot

Ionic compounds and polar compounds can dissolve in water and non polar compounds can not

Explain why or why not substances are soluble in water

Like dissolves like so anything polar (because water is polar) placed in water will dissolve

Differentiate between acids and bases and give examples for each

Acids have a hydrogen in them and bases have an OH in them. Acid example: HCl. Base example: LiOH

Describe the action of a pH buffer and explain the two main buffer systems acting in the human body

A weak acid and its conjugate base. one buffer system in the body is bicarbonate because we take in a lot of acidic foods and our blood pH has to remain around 7.4 so the bicarbonate keeps it at a good level

Differentiate between organic and inorganic compounds

Organic compounds contain carbon

Explain why carbon is the ideal element for life

It makes up more than 50% of dry mass, after water is taken away

Describe the five most common reaction types biomolecules may engage in

1. Functional group transfer

2. Redox reaction

3. Rearrangement

4. Dehydration synthesis

5. Hydrolysis

Cell components that are structures located in the cytoplasm of a eukaryotic cell...

mitochondrion, ribosome, Golgi body, chloroplast

Phospholipids contain a hydrophilic end ('head") and a hydrophobic end ("tail"). A hypothetical "microbullet" shot through a phospholipid bilayer, a membrane made up of phospholipids, would pass these ends in which order?

head, tail, tail, head

Arguments that support the endosymbiont theory...

-mitochondria and chloroplasts contain DNA

-mitochondria and chloroplasts can produce proteins

-mitochondria and chloroplast multiply by a process similar to prokaryotic cell division

-mitochondria and chloroplasts are surrounded by two membranes that differ considerably in their molecular composition

According to the fluid mosaic model of cell membranes, which of the following statements is FALSE?

d) membrane proteins can easily change their inside-out orientation (flip-flop) in the membrane

Most of the specific functions of biological membranes, such as the transport of substances into and out of a cell, are carried out by

proteins

Which of the following events in a bio-membrane is energetically unfavorable and will not occur spontaneously?

the change of the orientation in which a transmembrane protein is embedded in the membrane ("flip-flop")

In contrast to animal cells...

plant cells do not burst in a hypotonic environment

The sodium-potassium pump....

-Is an integral protein of the cell membrane

-moves sodium ions out of the cell wall

-uses ATP to move ions across the cell membrane

-changes its shape to transport ions against a concentration gradient

Which of the following substances can diffuse freely through the lipid bilayer of the cell membrane?

oxygen

When placed in distilled water, red blood cells take up water molecules rapidly and burst within a few seconds. Which mechanism is responsible for this rapid water influx?

the water molecules diffuse through specific channels called aquaporin embedded in the cell membrane

An orderly series of biochemical reactions with specific enzymes acting at each step is characteristic of

a metabolic pathway

Which of the following statements is FALSE?

d) all biochemical reactions in the cell are irreversible

The activation energy of a biochemical reaction...

-is lowered when an appropriate enzyme is present

-has to be invested to begin with

-is the reason why many reactions my occur without an enzyme

When a biochemical reaction has reached its equilibrium...

-the change in free energy is 0 (delta G=0)

-The forward change and reverse reaction proceed at the same rate

Enzymes...

-Bind substrates at their active site

-Act as catalysts

-are reaction specific

The activity of an enzyme may be influenced by...

-The presence of molecules that fir into allosteric sites

-The temperature of its own environment

-the presence of a competitive inhibitor

-the pH of its environment

An enzyme may lower the activation energy of a biochemical reaction by....

-Bringing the substrates close together at the active site

-bringing the substrates into a favorable orientation toward each other

NAD+ and FAD...

-Are coenzymes of enzymes acting in redo reactions

-Are organic molecules

Feedback inhibition in the metabolism of cells...

-is usually exerted through allosteric effects on enzymes

-often involves the first enzyme of a metabolic pathway

-is used to regulate the activity of many metabolic pathways

-frequently employs the end-product of a metabolic pathway as allosteric inhibitor

From knowing that carbon has the atomic number 6, you can conclude that..

-Carbon atoms have 6 protons

-neutral carbon atoms have 6 elections

Which of the following particles are formed, when electrons are transferred from sodium to chlorine during the formation of sodium chloride?

ions

Which of the following statements are FALSE?

d) hydrogen molecules (H-H) can form hydrogen bonds with each other

Which of the following statements about hydrogen bonds is TRUE?

they may form between a hydrogen atom and a negative atom

Carbon has the atomic number 6, oxygen the atomic number 8. The electronegativity of carbon is 2.5, the electronegativity of oxygen 3.5. Which type of chemical bonds would you expect these two atoms to form with each other?

polar covalent bonds

The atoms in water molecules are held together by

polar covalent bonds

Which of the following properties of water can NOT be explained by the formation of hydrogen bonds between water molecules?

lack of color

In an aqueous solution with a pH value of 9 the proton concentration is increased 1000-fold by addition of an acid. What is the pH value of this solution after changing the proton concentration?

5

List the four large classes of biomolecules

Carbohydrates, lipids, proteins, nucleic acids

Describe the different types of carbohydrates, their properties and functions

Monosaccharides- simple sugars

Oligosaccharides- two or three sugars

Polysaccharides- 4+ sugars; many glucoses

Describe the different types of lipids, their properties and functions

Triglycerides (neutral fats)

Phospholipids- amphipathic molecules

Steroids-signaling molecules(hormones)

Waxes- prevent water loss

Explain the four levels of protein structure and how this organization explains functional diversity; list the different functions of proteins

Primary- amino acid sequence

Secondary- hydrogen bonds between peptide groups

Tertiary- overall 3-D shape

Quaternary- multiple tertiary structures together

Describe the chemical and structural differences between DNA and RNA

DNA is a double strand of RNA

Which of the following organic compounds is made up of macromolecules?

Hemoglobin, cellulose, E. coli DNA, Glycogen

What functions is carried out by proteins?

enzymatic function, hormonal function, transport function, immune response

Ribosomes...

-Composed of a small and large subunit

-Are the molecular machines that produce proteins

-Not enclosed by a membrane

-Contain ribosomal RNA (rRNA) and proteins

Statements about reactions is true....

-The products of a reaction may have less free energy (G) than the reactants

-The products of a reaction may have more free energy (G) the reactants

-Reversible reactions tend to approach a dynamic equilibrium

-Many biochemical reactions in the cell are reversible

The activity of an enzyme may be increased by...

the presence of molecules that fit into allosteric sites

The Cell Theory states that

All organisms are composed of cells

The smooth endoplasmic reticulum is the production site of

lipids

Which of the following arguments does NOT support the endosymbiont theory?

Mitochondria and chloroplasts perform biochemical reactions that are not found in the cytoplasm of a eukaryotic cell.

Which of the following types of molecules are the major structural components of the cell membrane?

phospholipids and proteins

In contrast to facilitated diffusion, active transport of solutes across a membrane

enables cells to "pump" solutes against a concentration gradient

Which of the following statements about reactions is FALSE?

Many biochemical reactions in the cell are reversible

Which of the following statements about exergonic reactions is FALSE?

Their products have more energy than the reactants

The activation energy of a biochemical reaction

-Is lowered when an appropriate enzyme is present

-Is the reason why many reactions do not occur without an enzyme

-Has to be invested to begin the reaction

When a biochemical reaction has reached its equilibrium

-The change in free energy is zero

-The forward and reverse reaction proceed at the same rate

The activity of an enzyme may be increased by

the presence of a competitive inhibitor

An enzyme may lower the activation energy of a biochemical reaction by

-bringing the substrates close together at the active site.

-bringing the substrates into a favorable orientation toward each other.

-participating in the reaction temporarily, but coming out of it unchanged.

NAD+ and FAD

-are coenzymes of enzymes acting in Redox reactions.

-are organic molecules.

-are prosthetic groups of their enzymes

Feedback inhibition in the metabolism of cells

-is usually exerted through allosteric effects on enzymes.

-often involves the first enzyme of a metabolic pathway.

-is used to regulate the activity of many metabolic pathways.

-frequently employs the end-product of a metabolic pathway as allosteric inhibitor