ESCI 30 Midterm 1

The equation, C6H12O6 + 6O2 →6CO2 + 6H2O (ATP + heat), describes what process?

Cell respiration

Osmosis describes the movement of water from an area of high to low solute concentration.

False

The Calvin cycle is only capable of fixing carbon dioxide in the dark.

False

The amount of available energy that can be used to do work is called

Free energy

Which DNA strand is complementary to 5′-ATTCGGTGA-3′?

3′-TAAGCCACT-5′

Atmospheric pollution of Sulfur and nitrogen compounds from power plants leads to:

Acid rain that acidifies lakes and streams

Why do cells communicate? Check all that apply A.) To signal changes in the environment B.) To coordinate activities C.) To signal apoptosis D.) To signal presence of substrate E.) To signal absence of substrate

All of the above

What process best characterizes Ca2+ movement from the cytosol (low Ca2+ concentration) into the endoplasmic reticulum (high Ca2+ concentration)?

Calcium movement involves active transport

Identify the reactant that produces oxygen in the light reaction of photosynthesis

H2O

Isotopes are different forms of the same element that:

differ in their number of neutrons

What would happen to a plant that is treated with a chemical that prevents electrons from moving through the electron transport chain?

It could not generate an electrochemical H+ gradient across a membrane

Fats and fatty acids

Linear structure of a fatty acid causes solid formation at room temperature

Suppose you wanted to investigate ideas on how polymerization of prebiotic organic molecules may have occurred on the early Earth. Which of the following scenarios might best be utilized for this?

Mix some RNA nucleotides in water and repeatedly wet and dry them on clay

Which is NOT a trait of the DNA double helix?

The double helix configuration is as twisted and condensed as DNA can become

In the reaction, 6CO2 + 6H2O →C6H12O6 + 6O2, which side should energy be placed on?

The left side as this is an endergonic reaction

Which of the following statements about the electron transport chain in cell respiration is correct.?

The loss in free energy of the electron initially donated by NADH is used to transport

What would you predict about a reaction that has a ΔG < 0?

The reaction will yield energy and is spontaneous.

The ultimate source of energy for reactions in a plant is ...

The sun

Which membrane component is most important for allowing large, charged molecules to pass through the membrane?

Transmembrane proteins

Bacteria commonly use N-acyl homoserine lactone as a signal molecule to coordinate biofilm formation.

True

Fluorescence microscopy enables researchers to label and visualize a particular type of cellular protein or organelle.

True

Sulfur 35 (35S) is an isotope of 32S. These elements differ in their number of neutrons.

True

The presence of integral proteins allows membranes to be selectively permeable to certain molecules.

True

Whether a signaling molecule operates locally or over long distances, it must bind to a specific receptor to elicit a cellular response.

True

A comparison of mitochondria and chloroplast shows that ...

both generate ATP via a H+ electrochemical gradient.

The organelles most likely to have to ability to divide and reproduce themselves like a cell would be:

both mitochondria and chloroplasts

Which portion of the photosynthetic apparatus absorbs light?

both photosystem I and photosystem II

Protobionts are thought to be the first nonliving structures that evolved into living cells. A critical characteristic of a protobiont that is found in both modern day prokaryotes and eukaryotes is

boundary membrane that separates external from internal environments

When one atom loses an electron to another atom, it results in the formation of:

cations and anions that form ionic bonds

In which organelle of the plant does photosynthesis takes place?

chloroplast

A key is placed into a keyhole, then turned, and the door opens. When considering the components of cell signaling, the action of turning the key would best correspond to ...

conformational change in the receptor once bound to the hormone

When epidermal growth factor binds to a(n) ________ receptor, the receptor phosphorylates itself, triggering a signal transduction pathway.

enzyme-linked

A significant role played by pH buffers is to

limit major shifts in the amount of H+ and OH- in solution

The major class of macromolecules that stores energy and makes up the major component of plasma membranes are

lipids

Blue light has ________ energy than red light and is ________ by a green leaf.

more, absorbed

Carbon and hydrogen have similar electronegativities and combine together to form hydrocarbon molecules. What type of bonds form between these atoms?

nonpolar covalent

NADPH is produced by

the light reactions alone

The atomic number of an atom is:

the number of protons in the atom

As the radius of a cell increases:

the surface to volume ratio decreases

What statement about the major and minor grooves is TRUE? A.) The major and minor grooves are not present in bacterial cells, because they have circular chromosomes B.) The major and minor grooves are important for DNA binding proteins to attach to the DNA C.) The major groove is formed from pyrimidines and the minor groove is formed from purines D.) The major groove runs in the 5' to 3' direction and the minor groove runs in the 3' to 5' direction E.) None of these statements are TRUE

B.) The major and minor grooves are important for DNA binding proteins to attach to the DNA

A chemical reaction that has a positive ΔG is correctly described as:

Endergonic

Enzymes are consumed in chemical reactions and must therefore be replenished

False

All of the following are a form of potential energy that can be used by a cell except: A) ATP. B) nitrogen. C) an electrical/ion gradient. D) concentration gradient. E) NADH.

Nitrogen

The four most common elements in the human body are:

Oxygen, Nitrogen, Hydrogen, Carbon

What are the two major components of cell membranes?

Phospholipids and proteins

The best way to describe cellular membranes is:

fluid with lipid rafts

A new flower species has a unique photosynthetic pigment. The leaves of this plant appear to be blue-green. What wavelengths of visible light does this pigment reflect?

green and blue

Water ...

has cohesive properties

Passive diffusion ...

is a spontaneous process

How does an enzyme work to catalyze a reaction?

it lowers the activation energy of the reaction

The nucleotides within DNA are composed of a

phosphate group, deoxyribose sugar, nitrogenous base

In a single strand of DNA, nucleotides are connected by which type of bond?

phosphodiester

Succulent plants such as cacti or pineapple

produce 4-carbon malate in the first step of carbon fixation.

A plant performing photosynthesis will

produce oxygen and consume carbon dioxide.

Apoptosis in cells can be best described as ...

programmed cell death

A protein's ________ structure contains helixes and sheets that result from hydrogen bonding between carboxyl and amino groups of the polypeptide chain.

secondary

Diabetics can be given insulin that binds to receptors on cells throughout the body increasing glucose uptake. Insulin is an example of a ...

signal

You are given two nucleic acids; one RNA and the other DNA. What are the main features to determine which is the DNA?

thymine instead of uracil and is a double-stranded structure