General Biology Chapter 3-5 TEST

Green olives may be preserved in brine, which is 30% salt solution. How does this method of preservation prevent microorganisms from growing in olives?

A 30% salt solution is hypertonic to the bacteria, so they lose too much water and plasmolyze

The concentration of solutes in a red blood cell is about 2%, but red blood cells contain almost no sucrose or urea. Sucrose cannot pass through the membrane, but water and urea can. Osmosis would cause red blood cells to shrink the most when immersed in which of the following solutions?

A hypertonic sucrose solution

What would be LEAST likely to diffuse through a plasma membrane without the help of a transport protein?

A large polar molecule

In a hydrolysis reaction, blank, and in this process, water is....?

A polymer is broken up into its constituent monomers... consumed

The course of phosphate for a phosphorylation cascade is....?

ATP

Consider two cells with the same volume but with very different surface areas due to differences in their shapes. The cell with the larger surface area is likely to...?

Be involved in the rapid uptake of compounds from the cell's environment

What is correctly compared the extracellular matrix (ECM) of animal cells to cell walls of plant cells?

Both the ECM and the plant cell wall are composed of varying mixtures of proteins and carbohydrates

What does the addition of a phosphate groups do to a protein?

Can either activate or inactivate a protein

What molecule is most likely to passively diffuse across the plasma membrane?

Carbon dioxide

What is an example of a polymer?

Cellulose, a plant cell wall component

What is true about cytoskeleton?

Components of the cytoplasmic often mediate the movement of organelles within the cytoplasm

What is true about cotransport of solutes across a membrane?

Cotransport proteins can couple the "downhill" diffusion of the solute to the "uphill" transport

The type of bond that forms to join monomers (such as sugars and amino acids) into polymers (such as starch and proteins) is a(n) what bond?

Covalent

In eukaryotic cells, what is a second messengers that is produced as a response to an external signal such as a hormone?

Cyclic AMP

What is the process by which monomers are linked together to form polymers?

Dehydration or condensation reactions

When a protein is denatured, why does it lose its functionality?

Denaturation breaks the weak bonds, such as hydrogen bonds and van der Waals interactions, that hold the protein in its three-dimensional shape. Without the proper shape, the protein cannot function

Microtubules and microfilaments commonly work with which of the following to perform manny of their functions? A) Lysosomes B) Ribosomes C) Golgi apparatus D) RNA E) None of the listed responses are correct

E) Non of the listed responses are correct

A nursing infant is able to obtain disease-fighting antibodies, which are large protein molecules, from its mothers milk. These molecules probably enter the cells lining the baby's digestive tract via which process?

Endocytosis

Carbohydrates are used in our bodies mainly for....?

Energy storage and release

In terms of cellular function, what is the most important difference between prokaryotic and eukaryotic cells?

Eukaryotic cells are compartmentalized, which allows for specialization

A cell has a membrane potential of -100 mV (more negative inside than outside) and has 1,000 times more calcium ions outside the cell than inside. What best describes a mechanism by which Ca+2 enters the cell?

Facilitated diffusion of Ca2+ into the cell down its electrochemical gradient

What best describes facilitated diffusion?

Facilitated diffusion of solutes may occur through channel or transport proteins in the membrane

A G protein is active when...?

GTP is bound to it

A polysaccharide that is used for storing energy in human muscle and liver cells is...?

Glycogen

A researcher made an interesting observation about a protein made by the rough endoplasmic reticulum and eventually found in a cells plasma membrane. The protein in the plasma membrane was actually slightly different from the protein made in the ER. The protein was probably altered in the...?

Golgi apparatus

Enzyme molecules require a specific shape to perform their catalytic functions. What might alter the shape of an enzymatic protein?

Heating of a protein

The fatty acid tails of a phospholipid are blank because they ....?

Hydrophobic... have no charges to which water molecules can adhere

What correctly describes a general property of all electrogenic pumps?

It created a voltage difference across the membrane

Phospholipids are amphipathic. What does that mean?

It has both a hydrophobic and hydrophilic region

Bacterial cells are prokaryotic. Unlike a typical eukaryotic cell they...?

Lack membrane-bound organelles in their cytoplasm

The sex hormones estrogen, progesterone, and testosterone belong to which class of molecules?

Lipids

A mutation in the active site of adenylyl cyclase that inactivated it would most likely lead to...?

Lower activity of protein kinase A

What best describes the function of the rough endoplasmic reticulum?

Manufacturing

Receptors for signal molecules....?

May be found embedded in the plasma membrane, or found within the cytoplasm or nucleus

What is true about carbohydrates associated with the plasma membrane is correct?

Membrane carbohydrates function primarily in cell-cell recognition

Generally, animals cannot digest (hydrolyze) the glycosidic linkages between the glucose molecules in cellulose. How then do cows get enough nutrients from eating grass?

Microorganisms in their digestive tracts hydrolyze the cellulose to individual glucose units

Cilia and flagella move due to the interaction of the cytoskeleton with what?

Motor proteins

What type of cell is likely to have the most mitochondria?

Muscle cells in the legs of a marathon runner

Testosterone does NOT affect all cells for the body because...?

Not all cells have cytoplasmic receptors for testosterone

What is true about passive transport?

Passive transport permits the solute to move in either direction, but the net movement of the population of so,Ute occurs down the concentration gradient of the molecule

What is correct about the role phospholipids in the structure and function of biological membranes?

Phospholipids form a selectively permeable structure

Dye injected into a plant cell might be able to enter an adjacent cell through...?

Plasmodesmata

The general name for an enzyme that transfers phosphate groups from ATP to a protein is...?

Protein kinase

cAMP usually directly activates...?

Protein kinase A

Second messengers tend to be water-soluble and small. This accounts for their ability to...?

Rapidly move throughout the cell by diffusion

What enables a cell to pick up and concentrate a specific kind of molecule?

Receptor-mediated endocytosis

What features do prokaryotes and eukaryotes have in common?

Ribosomes, plasma membrane, cytoplasm

What group is primarily involved in synthesizing molecules needed by the cell?

Ribosomes, rough endoplasmic reticulum, and smooth endoplasmic reticulum

Nutritionally, saturated tricylglycerols are considered are considered to be less healthful than unsaturated triacylglycerols. What is the difference between them?

Saturated tricylglycerols have more hydrogen atoms that unsaturated triacylglycerols

The alpha helix and beta pleated sheet represent which level of protein structure?

Secondary structure

What is cell fractionation? Why is this process useful to scientists?

The breaking down of a cell into its smallest component parts It allows them to look at each individual organelle

The plasma membrane is referred to as a fluid mosaic structure. What about that model is true?

The fluid aspect of the membrane is due to the lateral and rotational movement of the phospholipids, and embedded proteins account for the mosaic aspect

Amylase is an enzyme that breaks down starch. Why can't the same enzyme break down cellulose?

The monosaccharide monomers in cellulose are bonded differently than in starch

Consider the transport of protons and sucrose into a plant cell by the sucrose-proton cotransport protein. Plant cells continuously produce a proton gradient by using the energy of ATP hydrolysis to pump protons out of the cell. Why, in the absence of sucrose, don't protons move back into the cell through the sucrose-proton cotransport protein?

The movement of protons through the cotransport protein cannot occur unless sucrose also moves at the same time

A dish of animal cells was grown in the presence of radioactive phosphorus. The phosphorus largely ended up in nucleotides inside the actively growing animal cells. In which cellular structure(s) would you predict the majority of the radioactive phosphorus to accumulate?

The nucleus

How does a hormone qualify as a long-distance signaling example?

The signal has to travel farther to reach a receptor

Active transport requires an input of energy and can also generate voltages across membranes. Based on this information, what is true about it?

The sodium/potassium pump hydrolyzes ATP and results in a net charge of +1 outside the cell membrane

The cellular response of a signal pathway that terminated at a transcription factor would be...?

The synthesis of mRNA

What is true about unsaturated fats?

They have double bonds in their fatty acid chains

Your intestine is lined with individual cells. No fluids leak between these cells from the gut into your body. Why?

Tight junctions are bound together to keep it from leaking

A single plant cell is placed in an isotonic solution. Salt is then added to the solution. What will occur as a result of the salt addition?

Water will leave the cell by osmosis, causing the volume of the cell to decrease

Briefly explain the Endosymbiont Theory. Which two organelles are the basis for this theory?

When two prokaryotic cell's get engulfed and form a eukaryotic cell Mitochondria and chloroplast