Bio Ch7 MB

endocytosis and exocytosis

-transported substances never physically cross the plasma membrane -requires cellular energy

Which of the following statements about the nuclear envelope are true?

-Nuclear pores are made up of a group of proteins that are collectively called the nuclear pore complex. -Molecules pass into and out of the nucleus through nuclear pores. -The nuclear envelope is composed of two lipid bilayers.

Endocytosis

-forms vesicles from inward folding of the plasma membrane -decreases the surface area of the plasma membrane

Exocytosis

-requires fusion of vesicles with the plasma membrane -secretes large molecules out of the cell -increases the surface area of the plasma membrane

Which of these structures stores, modifies, and packages products?

A

The Golgi apparatus has a polarity, or sidedness, to its structure and function. Which of the following statements correctly describes this polarity?

ALL!!! -Transport vesicles fuse with one side of the Golgi and leave from the opposite side. -Proteins in the membrane of the Golgi may be sorted and modified as they move from one side of the Golgi to the other. -Soluble proteins in the cisternae (interior) of the Golgi may be sorted and modified as they move from one side of the Golgi to the other. -Lipids in the membrane of the Golgi may be sorted and modified as they move from one side of the Golgi to the other.

Because of the high energy demand, you would also expect many proteins needed for _______ production to be imported into ________.

ATP, mitochondria

Part complete The eukaryotic cytoskeleton is a highly dynamic network of filaments and motor proteins. Which of the following correctly describe activities of these cytoskeletal components?

Actin filaments are required for cytoplasmic streaming.

Which of the following results provided evidence of a discrete nuclear localization signal somewhere on the nucleoplasmin protein?

After cleavage of the nucleoplasmin protein, only the tail segments appeared in the nucleus.

Choose the letter that indicates the organelle that contains most of a cell's DNA.

C

The structure that regulates the passage of material into and out of this bacterial cell is indicated by the letter _____.

C

The DNA-containing region of this bacterial cell is indicated by the letter _____.

D

Which of these provides the cell with structural support?

D

Which molecules do not normally cross the nuclear membrane?

DNA

All of the following are a part of a prokaryotic cell

DNA Plasma Membrane Cell Wall Ribosomes

Which of these is the double membrane that encloses the nucleus?

E

What is the most likely pathway taken by a newly synthesized protein that will be secreted by a cell?

ER → Golgi → vesicles that fuse with plasma membrane

True or false? Large proteins containing a nuclear localization signal (NLS) bind to the nuclear pore and enter the nucleus without any expenditure of energy.

False

True or false? Proteins produced during the "chase" phase of a pulse-chase experiment are labeled with radioactive material.

False

_____ are surface appendages that allow a bacterium to stick to a surface.

Fimbriae

What is the first step in a pulse-chase experiment?

Incubating cells with a labeled molecule

Which of the following correctly matches a component of the cytoskeleton to one of its functions?

Microtubules move chromosomes.

Which of the following statements about the cytoskeleton is true?

Movement of cilia and flagella is the result of motor proteins causing microtubules to move relative to each other.

Nucleoplasmin is a nuclear protein. This protein was divided into two segments and linked to the same large cytoplasmic protein, generating two fusion proteins. After injecting these fusion proteins into a cell, one of the proteins was found in the nucleus and the other in the cytoplasm. Which of the following conclusions can be drawn from these results?

Only one of the two fusion proteins possesses a nuclear localization signal

What path does a protein in the secretory pathway take, starting from its site of synthesis?

Rough ER, Golgi apparatus, secretory vesicles, plasma membrane

Scientists have found that polypeptides which are normally synthesized in the endoplasmic reticulum are about 20 amino acids longer when they are synthesized by ribosomes not attached to the endoplasmic reticulum. What is a possible explanation for the greater length of these polypeptides?

The 20 amino acids serve as a signal (peptide) sequence that directs the forming polypeptides to the endoplasmic reticulum, where they are cleaved off during processing.

During a pulse-chase experiment, photographic emulsions were prepared at different times during the chase, and radioactive spots were detected at the following times and locations: 5 minutes: rough ER; 10 minutes: Golgi apparatus; 40 minutes: endosomes; 70 minutes: lysosomes; 140 minutes: lysosomes. Which of the following conclusions can be drawn from these results?

The final destination of the proteins was the lysosome.

Which of the following statements about the nuclear envelope is false?

The nuclear envelope is continuous with the Golgi apparatus.

Which of the following correctly pairs the organelle with the function of the organelle in prokaryotes?

The photosynthetic membranes have a large surface area to hold pigments and enzymes to increase food production.

Molecular zip codes direct molecules to particular destinations in the cell. How are these signals read?

They bind to receptor proteins.

Which statements are true for chloroplasts?

They contain the green pigment chlorophyll. 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.

What are three attributes of mitochondria and chloroplasts that suggest they were once free-living bacteria?

They have their own small, often circular chromosomes; they produce their own ribosomes; and they replicate independently of cellular division.

A prokaryotic cell is distinct from a eukaryotic cell because a prokaryotic cell lacks _____.

a nucleus

What types of proteins are radioactively labeled in this pulse-chase experiment?

all proteins being synthesized during the time of the pulse

Lysosomes are considered to be part of the endomembrane system because they ________.

are formed from products synthesized by the endoplasmic reticulum and processed by the Golgi

_____ is/are identical in structure to centrioles.

basal bodies

What name is given to the rigid structure, found outside the plasma membrane, that surrounds and supports the bacterial cell?

cell wall

plant cell only

cellulose cell wall, chloroplast, central vacuole

animal cell only

centriole

The _____ is composed of DNA and protein.

chromatin

The radiolabeled proteins would likely be found in the ________, where myosin and actin filaments are involved in ________.

cytosol, muscle contractions

Which organelle plays a role in intracellular digestion?

lysosome

Pancreatic cells, which secrete a large amount of digestive enzymes, are labeled with radioactive leucine and then chased for several hours with nonradioactive leucine. Photographic emulsions are prepared at different times during the chase. Where would the black spots appear on an emulsion prepared 3 hours after the pulse?

exterior of the cell

Which of the following proteins are synthesized by bound ribosomes?

insulin ER protein lysosomal enzyme

Many cell organelles, most notably the nucleus, are anchored by ______________ which are assembled from a diverse class of proteins.

intermediate filaments

The only cytoskeletal fibers not associated with intracellular movement or whole cell locomotion are the

intermediate filaments

Endocytosis moves materials _____ a cell via _____.

into ... membranous vesicles

eukaryotic only

lysosome, mitochondria, nucleolus

During muscle contractions, myosin motor proteins move across tracks of

microfilaments

The extension of pseudopodia in amoeba is due to the regulated assembly and destruction of

microfilaments

Centrosomes are sites where protein dimers assemble into

microtubules

In eukaryotic flagella, the fibers that slide past one another due to the activity of dynein proteins are

microtubules

The cilia and flagella of eukaryotic cells are composed of _____.

microtubules

Which of these are hollow rods that shape and support the cell?

microtubules

Both plant and animal cells

mitochondria plasma membrane nucleus cytoskeleton golgi ER

Which of these organelles carries out cellular respiration?

mitochondrion

Which organelle is the primary site of ATP synthesis in eukaryotic cells?

mitochondrion

Which plant cell organelle contains its own DNA and ribosomes?

mitochondrion

Which structure is common to plant and animal cells?

mitochondrion

What scientific hypotheses can be tested by a pulse-chase experiment?

movement of molecules through a cell over time

Prokaryotic only

nucleoid

Where is a bacterial cell's DNA found?

nucleoid region

Ribosomal subunits are manufactured by the _____.

nucleolus

A small protein (molecular weight = 25,000 daltons) is injected into a cell and observed in the nucleus a short time later. What type of transport has taken place?

passive transport

Which of these organelles produces H2O2 as a by-product?

peroxisome

A white blood cell engulfing a bacterium is an example of _____.

phagocytosis

The _____ is a selective barrier, regulating the passage of material into and out of the cell.

plasma membrane

The _____ is the bacterial structure that acts as a selective barrier, allowing nutrients to enter the cell and wastes to leave the cell.

plasma membrane

both prokaryotes and eukaryotes

plasma membrane flagella ribosomes

What is a function of a bacterium's capsule?

protection

Large numbers of ribosomes are present in cells that specialize in producing which of the following molecules?

proteins

In bacterium, where are proteins synthesized?

ribosomes

sites of protein synthesis

ribosomes

Which structure is the site of the synthesis of proteins that may be exported from the cell?

rough ER

Which of these organelles manufactures proteins bound for secretion out of the cell?

rough endoplasmic reticulum

The liver is involved in detoxification of many poisons and drugs. Which of the following structures is primarily involved in this process and, therefore, abundant in liver cells?

smooth ER

Where is calcium stored?

smooth endoplasmic reticulum

Which type of organelle or structure is primarily involved in the synthesis of oils, phospholipids, and steroids?

smooth endoplasmic reticulum

You can recognize the process of pinocytosis when _____.

the cell is engulfing extracellular fluid

Tay-Sachs disease is a human genetic abnormality that results in cells accumulating and becoming clogged with very large, complex, undigested lipids. Which cellular organelle must be involved in this condition?

the lysosome

organelles of the endomembrane system

these

plant organelle functions

these

the pathway of secretory proteins

these

In experiments to test whether a protein can enter the nucleus, why would proteins be labeled with fluorescent molecules?

to make the proteins easy to see

Which organelle often takes up much of the volume of a plant cell?

vacuole