Bio 1 - chapter 6 & 7

If a red blood cell and a plant cell were placed in seawater, what would happen to the two types of cells?

Both cells would lose water; the red blood cell would shrivel, and the plant plasma membrane would pull away from the cell wall.

Which of the following molecules are most abundant in the plasma membrane?

Phospholipids

Which of the following statements about the role of phospholipids in the structure and function of biological membranes is correct?

Phospholipids form a selectively permeable structure.

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

have no membrane-bounded organelles in their cytoplasm

Observing a fluorescent micrograph cell with intermediate filaments would help you identify the cell as a __________.

human skin cell

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

motor proteins

Microfilaments function in cell motility including __________.

muscle contraction, amoeboid movement, and cytoplasmic streaming in plants

The endoplasmic reticulum is part of the endomembrane system, which also includes the __________.

nuclear envelope, the Golgi apparatus, lysosomes, and vesicles

The region of a bacterial cell that contains the genetic material is called the __________.

nucleoid

Cells are small because __________.

of the geometric relationships between surface and volume

__________ are membrane-bound metabolic compartments that specialize in the production of hydrogen peroxide (H2O2) and its conversion to water.

peroxisomes

Which of the following cell structures exhibits selective permeability between a cell and its external environment?

plasma membrane

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

plasmodesmata

Cell junctions in plant cells are called __________, and communicating junctions in animal cells are called __________.

plasmodesmata; gap junctions

Which of the following is present in a prokaryotic cell?

ribosomes

You would expect a cell with an extensive Golgi apparatus to ________

secrete a lot of protein

Evidence that supports the prokaryotic origins of mitochondria and chloroplasts are all of the following except __________.

that mitochondria and chloroplasts have multiple copies of linear DNA molecules associated with their inner membranes

A substance moving from outside the cell into the cytoplasm must pass through __________.

the plasma membrane

The plasma membrane exhibits selective permeability. This means that __________.

the plasma membrane allows some substances to flow through it more easily than others

The function of the rough endoplasmic reticulum (RER) is __________.

to synthesize proteins that are secreted as glycoproteins

The internal solute concentration of a plant cell is about 0.8M. To demonstrate plasmolysis (shriveling), it would be necessary to suspend the cell in what solution?

1.0M (hypertonic)

Which of the following plant cells would exhibit the most turgor pressure?

A cell placed in a hypotonic solution a back pressure on the cell, called turgor pressure, that opposes further water uptake. At this point, the cell is turgid (very firm), which is the healthy state for most plant cells. Plants that are not woody, such as most houseplants, depend for mechanical support on cells kept turgid by a surrounding hypotonic solution. If a plant's cells and their surroundings are isotonic, there is no net tendency for water to enter, and the cells become flaccid (limp).

Which of the following would be least likely to diffuse through a plasma membrane without the help of a transport protein?

A large polar molecule

Which of the following substances would be most likely to pass through the plasma membrane without the help of a transport protein?

A nonpolar molecule, such as a hydrocarbon (co2 and o2) - hydrophobic can cross lipid bilayer

Which of the following is a correct difference between active transport and facilitated diffusion?

Active transport requires energy from ATP, and facilitated diffusion does not.

How does cholesterol affect membrane fluidity?

At body temperature, it makes the membrane less fluid.

Cells A and B are the same size, shape, and temperature, but cell A is metabolically less active than cell B; cell B is actively converting oxygen to water in cellular respiration. Oxygen will diffuse more rapidly into cell __________ because __________.

B; the diffusion gradient in cell B is steeper

Why is energy required for active transport?

Because it moves solutes against their concentration gradient

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

Eukaryotic cells are compartmentalized, which allows for specialization.

Which of the following molecules is most likely to passively diffuse across the plasma membrane?

Carbon dioxide

What function do carbohydrates fulfill in the plasma membrane?

Cell-to-cell recognition

Which statement about the cytoskeleton is true?

Components of the cytoskeleton often mediate the movement of organelles within the cytoplasm.

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

Endocytosis

Which of the following processes and organelle(s) accounts for the replacement of lipids and proteins lost from the plasma membrane?

Exocytosis and smooth and rough ER

Which of these statements describes some aspect of facilitated diffusion?

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

Which of the following statements about diffusion is true?

It is a passive process.

Which of the following statements concerning carbohydrates associated with the plasma membrane is correct?

Membrane carbohydrates function primarily in cell-cell recognition.

Which of the following statements about passive transport is correct?

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

Which of the following structural arrangements of the components in biological membranes facilitates the cell membrane's property of selective permeability?

Proteins embedded in two layers of phospholipids

How does the "fluid mosaic model" describe the structure of the plasma membrane?

Proteins in the membrane contribute to the mosaic quality of the membrane while the lateral and rotational movements of phospholipids contribute to its fluidity.

Which of the following groups is primarily involved in synthesizing molecules needed by the cell?

Ribosomes, rough endoplasmic reticulum, and smooth endoplasmic reticulum

What is the functional connection between the nucleolus, nuclear pores, and the nuclear membrane?

Subunits of ribosomes are assembled in the nucleolus and pass through the nuclear membrane via the nuclear pores.

Red blood cells contain approximately a 2% concentration of solutes. A red blood cell is placed into a solution that contains a 4% concentration of solutes to which the cell is not permeable. What will happen to the red blood cell?

The cell will decrease in size as water flows out of it.

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

The intestinal cells are bound together by tight junctions.

A cell is placed into a solution and the cell shrinks. Which of the following is true regarding the solution?

The solution is hypertonic.

Which of the following is correct regarding peripheral proteins?

These proteins are found only on the surface of the plasma membrane.

Which of the following is correct regarding integral proteins

These proteins exhibit both hydrophilic and hydrophobic properties.

The extracellular matrix of the animal cell has all of the following molecular components except __________.

a middle lamella

The organelle that is a plant cell's compartment for the storage of inorganic ions such as potassium and chloride is the __________.

central vacuole

animal cells have unique organelles called __________ that are composed of structures called __________.

centrosomes; centrioles

In facilitated diffusion, __________ proteins provide openings in the plasma membrane for substances to flow through without changing structure, and __________ proteins allow passage of substances through the plasma membrane after undergoing a subtle change in shape.

channel; carrier

which is false in respect to cells' chromosomes?

chromosomes are only visible as a cell is about to divide true: Chromosomes contain DNA and proteins. Chromosomes are present throughout a cell's reproductive cycle Chromosomes exist even when cells are not actively synthesizing proteins.

Basal bodies are most closely associated with which of the following cell components?

cilia

A protein that ultimately functions in the plasma membrane of a cell is most likely to have been synthesized __________.

in the rough endoplasmic reticulum

The walls of plant cells are largely composed of polysaccharides and proteins that are synthesized __________.

in the rough endoplasmic reticulum and in the Golgi apparatus

The network of fibers that organizes structures and activities in a cell __________.

is the cytoskeleton

All cells have voltages across their membranes. This voltage is called a(n) __________ and is often maintained by __________.

membrane potential; electrogenic pumps

The endosymbiont theory explains the origins of __________.

mitochondria and chloroplasts

The sodium-potassium pump __________.

transports sodium ions out of the cell and transports potassium ions into the cell

Cell motility, which includes changes both in cell location and in the movement of cell parts, requires interactions of the cytoskeleton __________.

with motor proteins