Bio Unit 2

which of the following choices correctly matches a tool and its proper application?

cell fractionation to study the function of specific organelles

beginning within the nucleus, the first step leading to the synthesis of a polypeptide is _____

transferring of information from DNA to messenger RNA

which of the following proteins are synthesized by bound ribosomes?

lysosomal enzyme, insulin, ER protein

Based on these data, what is the most likely function of the cells in this experiment?

phagocytosis

which of the following common traits of chloroplasts and mitochondria?

both have their own DNA

Some of the following statements are true for chloroplasts; others are true for mitochondria. Which statements are true for chloroplasts? Select the three that apply.

they have membranous sacs called thylakoids that are surrounded by a fluid called stroma, they are the sites of reactions that convert solar energy into chemical energy, they contain the green pigment chlorophyll

To understand how cells function as the fundamental unit of life, you must first become familiar with the individual roles of the cellular structures and organelles. Drag the labels on the left onto the diagram of the animal cell to correctly identify the function performed by each cellular structure.

which of these cell junctions form a barrier to the passage of materials?

tight junctions

the primary role of ______ is to bind animal cells together

desmosomes

_______ aid in the coordination of the activities of adjacent animal cells

gap (communication) junctions

Motor proteins are responsible for moving vesicles and organelles within the cell. Motor proteins move along protein “tracks.” In the example shown in the Visualizing figure, what are those tracks made of?

actin

what molecules and cellular components pass through the nuclear pore during normal cellular activity?

ribosomal subunits, mRNA

which of the following expresses the concept of emergent properties?

the parts of a car, once assembled, result in a structure that can provide transportation

membrane phospholipids

may have “kinks” in their tails, each caused by the presence of a double bond between carbons

one difference between eukaryotic and prokaryotic cells is that eukaryotic cells

have membrane-enclosed organelles, which are lacking in prokaryotic cells

which of the following is the smallest biological structure that would most likely be visible with a standard research-grade light microscope

chloroplast

which of the following is present in a prokaryotic cell?

ribosome

which structure is common to plant and animal cells

mitochondrion

which of the following statements best describes one major difference between prokaryotic cells and eukaryotic cells?

eukaryotic cells have membrane-bound organelles, while prokaryotic cells do not

which organelle plays a role in intracellular digestion?

lysosome

which of the following statements about the endomembrane system is correct?

proteins that will be secreted from the cell are likely to be found in closed spaces bounded by membranes of the endomembrane system

which structure is part of the endomembrane system?

golgi apparatus

which of the following organelles often occupy the majority of the volume of a plant cell?

central vacuole

which of the following organelles is primarily responsible for the production and modification of polysaccharides that will be secreted?

golgi apparatus

a cell with a predominance of rough endoplasmic reticulum is most likely involved in which of the following processes?

producing large quantities of proteins for secretion

Which of the following organelles is most likely defective in Tay-Sachs disease?

the lysosome

which statement correctly describes an endomembrane function?

products of the ER are usually modified during their transit from the cis to the trans region of the Golgi apparatus

mitochondria are found in _______

plant and animal cells

which of the following structures is independent of the endomembrane system in eukaryotic cells?

chloroplast

disruption of the function of which of the following organelles would result in a dramatic decrease in ATP synthesis in eukaryotic cells?

mitochondrion

A particular cell contains the following molecules and structures: enzymes, DNA, ribosomes, plasma membrane, and mitochondria. Based on this composition, it could be a cell from which of the following organisms?

nearly any eukaryotic organism

a young child who suffers from a metabolic disease is always tired and fatigued. which of the following organelles is most likely malfunctioning in this disease?

mitochondria

ions can travel directly from the cytoplasm of one animal cell to the cytoplasm of an adjacent cell through which of the following structures?

gap junctions

Which statements about the fluid mosaic structure of a membrane are correct? Select the three correct statements.

The framework of a membrane is a bilayer of phospholipids with their hydrophilic heads facing the aqueous environment inside and outside of the cell and their hydrophobic tails clustered in the center.

Because membranes are fluid, membrane proteins and phospholipids can drift about in the membrane.

The diverse proteins found in and attached to membranes perform many important functions.

In this diagram of the plasma membranes of two adjoining cells, identify the protein indicated by the white arrow, including its function.

a receptor protein that binds with a signaling molecule and relays the message into the cell by activating other molecules inside the cell

You are working on a team that is designing a new drug. For this drug to work, it must enter the cytoplasm of specific target cells. Which of the following would be a factor that determines whether the molecule selectively enters the target cells?

the similarity of the drug molecule to other molecules that are transported into the target cells

Which of the following statements about the conditions shown in the U-shaped tube are true?

Water is tightly clustered around the hydrophilic solute molecules on both sides of the membrane. There is less free water in the right arm of the tube than in the left arm of the tube.

If more sugar were added to the solution on the left side of the tube, what would happen to the water level on the right side of the tube?

The water level would go down.

If the pores in the selectively permeable membrane became larger, but still not large enough to let the sugar pass through, what would happen during osmosis in the U-shaped tube compared to what is shown in the figure?

The final water levels would be the same as shown in the figure, but the solutions would reach near equal concentrations faster.

Which of the following molecules can cross the lipid bilayers of a membrane directly, without a transport protein or other mechanism? Select all that apply.

water, oxygen, carbon dioxide, lipids

A semipermeable membrane is placed between the following solutions.

Which solution will decrease in volume?

solution A

A semipermeable membrane is placed between the following solutions.

Which solution will increase in volume?

solution D

Is the hypothesis supported?

The hypothesis is NOT supported. The egg in the corn syrup lost weight (water) over time, indicating that corn syrup is hypertonic to the egg.

How are the results of the hemodialysis experiment involving diffusion (Experiment 1) similar to the results of the egg osmosis experiment (Experiment 2)?

Excess water from the blood moved to the hypertonic dialysate fluid, similar to how water from the egg moved to the hypertonic corn syrup.

Hydrophobic substances like salad oil are

nonpolar molecules that do not have an affinity for water molecules.

How do membrane phospholipids interact with water?

The polar heads interact with water; the nonpolar tails do not.

Which of the following is a major difference between prokaryotic and eukaryotic cells?

Most prokaryotic cells have no internal membranes; eukaryotic cells do.

Which of the following statements is true regarding potential energy?

Potential energy is the energy possessed by matter due to its location or structure.

Which of the following statements about a typical plasma membrane is correct?

The two sides of the plasma membrane have different lipid and protein composition.

function of structure E

stabilization of the phospholipids

identify structure D

phospholipid bilayer of membrane

identify structure A

glycoprotein

Which of the following best describes the structure of a biological membrane?

two layers of phospholipids, with proteins either crossing the layers or on the surface of the layers

Which of the following statements best describes a characteristic feature of integral membrane proteins?

They are amphipathic, with at least one hydrophobic region.

According to the fluid mosaic model of membrane structure, proteins of the membrane are mostly

embedded in a lipid bilayer.

Which of the following factors would tend to increase membrane fluidity?

a greater proportion of unsaturated phospholipids

Which of the following statements best describes a characteristic of biological membranes?

Phospholipids move laterally within the plane of the membrane.

Which of the following statements best explains how the membranes in winter wheat are able to remain fluid in extremely cold temperatures?

The membranes contain an increased proportion of unsaturated phospholipids.

An animal cell that lacks carbohydrates on the external surface of its plasma membrane would likely be impaired in which of the following functions?

cell-cell recognition

Which of the following types of molecules are most likely to be excluded from the hydrophobic portion of the phospholipid bilayer?

peripheral membrane proteins

Which of the following statements best explains the reason that lipids and proteins are free to move laterally in membranes?

There are only weak hydrophobic interactions in the interior of the membrane.

Which of the following types of molecules will diffuse through a cell membrane most readily?

small hydrophobic molecules

Which of the following molecules would likely diffuse through the lipid bilayer of a plasma membrane most rapidly?

O2

osmosis is a type of diffusion

true

What property of dishwashing liquid (detergent) makes it useful to wash grease from pans?  

Amphipathic nature

True or false? The water-soluble portion of a phospholipid is the polar head, which generally consists of a glycerol molecule linked to a phosphate group.  

true

If a red blood cell is placed in a salt solution and bursts, what is the tonicity of the solution relative to the interior of the cell?

hypotonic

facilitated diffusion is a type of

passive transport

structure A is a

solute

structure B is a

transport protein

Which of the following statements about osmosis is correct?

The presence of aquaporins (proteins that form water channels in the membrane) speeds up the process of osmosis.

Which of the following statements best describes a characteristic feature of diffusion?

It is a passive process in which molecules move from a region of higher concentration to a region of lower concentration.

Which of the following statements best describes a characteristic feature of osmosis?

In osmosis, water moves across a membrane from areas of lower solute concentration to areas of higher solute concentration.

Which of the following statements best describes the relationship between the solutions on both sides of the U-tube?

side A is isotonic to side B

What will happen to a red blood cell (RBC), which has an internal ion content of about 0.9%, if it is placed into a beaker of pure water?

The cell will shrink because the water in the beaker is hypertonic relative to the cytoplasm of the RBC.

Which of the following results is most likely when a plant cell is submerged in a hypertonic solution?

Plasmolysis will shrink the interior of the cell.

Which of the following molecular movements is due to diffusion or osmosis?

When a plant cell is placed in concentrated salt water, water moves out of the cell.

Which statement is correct?

The contents of a red blood cell are hyperosmotic to distilled water.

Considering this graph, under which condition is phosphofructokinase more active?

Phosphofructokinase is more active at low ATPATP concentration

Given what you know about glycolysis and regulation of metabolism by this enzyme, what is the mechanism by which phosphofructokinase activity differs depending on ATPATP concentration?

Phosphofructokinase is an allosteric enzyme that is inhibited by ATPATP and stimulated by AMP

Which of the following is true for all exergonic reactions?

The reaction proceeds with a net release of free energy

Which of the following is the most correct interpretation of the figure?

ATP is a molecule that acts as an intermediary to store chemical energy for cellular work

Two molecules with the chemical formulas C6H12O6C6H12O6 and C6H12O2C6H12O2 are probably

a monosaccharide and a fatty acid

Which of the following is true of the energy levels of electrons in shells?

Valence electrons have a higher energy level than those in other filled shells.

A covalent bond is likely to be polar when

one of the atoms sharing electrons is more electronegative than the other.

What process occurs in Box A?

glycolysis

What process occurs within Box B?

the citric acid cycle

What molecule is indicated by the letter D?

oxygen

Which term describes the degree to which an element attracts electrons?

Electronegativity

Which terms describe two atoms when they form a bond in which electrons are completely transferred from one atom to the other?

anion and cation

Which of the following statements is true of the bonds in a water molecule?

oxygen holds electrons more tightly than hydrogen does, and the net charge is zero.

Which of the following statements is not true of most cellular redox reactions?

a hydrogen atom is transferred to the atom that loses an electron

What kind of bond is formed when lithium and fluorine combine to form lithium fluoride?

ionic

Gaseous hydrogen burns in the presence of oxygen to form water:

2H₂ + O₂ → 2H₂ O + energy

Which molecule is oxidized and what kind of bond is formed?

hydrogen, polar

The immediate energy source that drives ATPATP synthesis by ATPATP synthase during oxidative phosphorylation is the

H+ concentration gradient across the membrane holding ATPATP synthase

Which of the following is the most important result of the process of cellular respiration in biological systems?

transforming the energy in glucose and related molecules into a chemical form that cells can use for work

Which metabolic pathway is common to both fermentation and cellular respiration of a glucose molecule?

glycolysis

When a glucose molecule loses a hydrogen atom in an oxidation-reduction reaction, the glucose molecule is ________

oxidized

Which of the following statements best describes what happens to a molecule of NAD⁺ (nicotinamide adenine dinucleotide) when it gains a hydrogen atom?

NAD⁺ becomes reduced.