Chapter 4 Mastering Biology HW

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

C. The plasma membrane is selectively permeable.

Which of the following is NOT an example of an organelle found within an animal cell?

Cell walls are found in plant cells, but not in animal cells.

__________ is the most prevalent glycoprotein in the extracellular matrix

Collagen; collagen can comprise 40% of the protein in your body.

Peroxisomes are organelles that are involved in the _____.

Peroxisomes break down fatty acids for fuel, and they are involved in the detoxification of alcohol and other harmful substances.

Smooth ER

Site of lipid synthesis

The primary role of _____ is to bind animal cells together.

The primary role of desmosomes (anchoring junctions) is to bind cells together.

Structures found within a eukaryotic cell and performing specific tasks are collectively termed __________.

organelles These "little organs" perform a variety of functions, including protein production, energy processing, and breakdown of various molecules.

What is the function of a bacterium's capsule?

protection A bacterium's capsule has a protective role.

In a bacterium, where are proteins synthesized?

ribosomes Ribosomes are involved in the manufacture of polypeptides (proteins).

Which of these manufactures cellular membranes by adding membrane proteins and phospholipids to its own membrane?

rough endoplasmic reticulum As membrane proteins grow from ribosomes on rough ER, the proteins are embedded into the rough ER membrane.

The architecture of cell surfaces can be viewed in the most detail using a __________.

scanning electron microscope The scanning electron microscope uses an electron beam to provide a detailed picture of the outlines of the surface.

Nucleus

stores genetic information of the cell

Ribosomes

works with mRNA to synthesize proteins

Ribosomal subunits are manufactured by the _____.

nucleolus

The term resolving power refers to _____.

the clarity of the image in showing two objects as separate Resolving power is the ability to see two points or objects as separate.

To enter or leave any cell, substances must pass through _____.

the plasma membrane The plasma membrane defines the boundary of the cell.

In eukaryotic cells the first step in protein synthesis is the _____.

transferring of information from DNA to messenger RNA Transcription is the first of the two main steps of protein synthesis.

_____ is/are identical in structure to centrioles.

Basal bodies and centrioles have identical structures.

Mitochondrion

Converts chemical fuel into packets of chemical energy (ATP) that can power the cell

Mitochondria

Coverts chemical fuel into packets of chemical energy that can power the cell.

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

D) The nucleoid region contains DNA.

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

Fimbriae Fimbriae enable bacterial cells to stick to a surface.

The cells of a person with adrenoleukodystrophy (ALD) swell with a buildup of fatty acids. In other words, fatty acids are not being broken down. Which organelle is most likely failing to function correctly?

Lysosome This organelle functions to remove unwanted or unneeded material from the cell.

You have identified a new organism. It has ribosomes, plasmodesmata, and cell walls made of cellulose. This new organism is most likely a(n) __________.

Plant Plant cells have cell walls that are made of cellulose and plasmodesmata, which are cytoplasmic channels that connect adjacent cells.

What name is given to the process in which pre-mRNA is edited into mRNA?

RNA processing RNA processing edits the RNA transcript that has been assembled along a DNA template.

One of the ways smooth endoplasmic reticulum (ER) differs from rough endoplasmic reticulum is that rough ER is covered by

Ribosomes Ribosomes dock on the rough ER, and proteins are completed inside the rough ER.

_____ are the sites of protein synthesis.

Ribosomes are the site of protein synthesis.

Where are lipids made in the cell?

Smooth ER

One function of the central vacuole in plant cells is facilitating cell growth: the central vacuole absorbs water and increases in size, expanding the volume and size of the plant cell while doing so. Animal cells, however, do not grow by this method. What is an essential difference between animal and plant cells that could explain how a plant cell can withstand this expansion of the central vacuole?

The plant cell wall provides a more rigid structure. The plant cell can use the central vacuole for growth because the cell wall is rigid.

What structure acts as a selective barrier, regulating the traffic of materials into and out of the cell?

The plasma membrane surrounds the cell and regulates the movement of materials into and out of the cell.

Which cellular organelle is required for photosynthesis to occur in eukaryotic cells?

chloroplast Chloroplasts contain the green pigment chlorophyll and enzymes and other molecules that function in the photosynthetic production of food.

The _____ is composed of DNA and protein.

chromatin

The function of the chloroplast is to _____.

convert light energy to chemical energy The function of the chloroplast is to convert light energy from the sun to the chemical energy of a glucose molecule.

Which of the following organelles is found only in animal cells and NOT in most plant cells?

lysosome This organelle is found only in animal cells. Most plant cells do not have a lysosome.

Which of the following correctly matches an organelle with its function? The __________ functions in __________.

lysosome ... recycling of damaged organelles Lysosomes contain hydrolytic enzymes that also digest ingested food.

RNA processing converts the RNA transcript into _____.

mRNA

Where is a bacterial cell's DNA found?

nucleoid region Bacteria lack a nucleus; their DNA is found in the nucleoid region.

Where is the genetic information of the cell stored?

nucleus

Plant Cell Wall

strong, protective structure made from cellulose fibrils.

If you wished to clearly observe the organelles inside of a white blood cell, which type of microscope would you choose?

transmission electron microscope

_____ aid in the coordination of the activities of adjacent animal cells.

Gap (communicating) junctions Gap junctions allow for the passage of material between cells, thus facilitating communication between these cells.

Which of the following organelles breaks down worn-out organelles?

Lysosomes: they contain digestive enzymes and break down worn-out organelles.

Cholorplast

Makes food by converting light energy into chemical energy

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

Microtubules Eukaryotic cilia and flagella are composed of microtubules.

When elongated, tube-shaped cells from the lining of the intestine are treated with a certain chemical, the cells sag and become rounded. The internal structures disrupted by this chemical are probably __________.

Microtubules Microtubules are cytoskeletal components, and the shape of a cell is determined by its cytoskeleton.

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

Microtubules are rods that also play a role in organelle movement.

Golgi Apparatus

Modifies and packages proteins

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

Peroxisomes produce hydrogen peroxide as a by-product of their metabolic processes.

Central Vacuole

Regulates cytoplasm composition, creates internal pressure, and stores cell compounds.

What carries instructions for making proteins from the nucleus into the cytoplasm?

The "m" in mRNA stands for "messenger"; mRNA is the messenger that carries genetic instructions from the nucleus to the cytoplasm.

Which of the following is the most likely consequence for a cell lacking functional lysosomes?

The cell becomes crowded with undigested wastes. A lysosome is a membrane-enclosed sac of hydrolytic enzymes that the cell uses to digest macromolecules—in some cases, recycling the cell's own organic material.

The structural framework in a cell is the

The cytoskeleton is the structural framework in a cell ("cyto" refers to cell and "skeleton" refers to a structural framework).

Pancreatic cells produce large amounts of protein. About how many ribosomes would you expect there to be in a pancreatic cell?

There are several million ribosomes in cells, such as the cells in the pancreas that produce digestive enzymes.

Which of these cell junctions form a barrier to the passage of materials? a. keratin fibers b. plasmodesmata c. tight junctions d. gap (communicating) junctions e. desmosomes (anchoring junctions)

Tight junctions form a barrier that prevents fluids from moving between cells.

What name is given to the process in which a strand of DNA is used as a template for the manufacture of a strand of pre-mRNA?

Transcription: is the process by which a DNA template is used for the manufacture of several different types of RNA.

What name is given to the process in which the information encoded in a strand of mRNA is used to construct a protein?

Translation: is the process by which information encoded in RNA is used to manufacture a polypeptide.

Chloroplasts are found in __________.

plant cells and some protists Chloroplasts are lens-shaped organelles found in leaves and other green organs of plants and photosynthetic protists.

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 The plasma membrane is selectively permeable.

Which of the following is part of the endomembrane system?

The endomembrane system includes the ER, the Golgi apparatus, lysosomes, and vesicles. It manufactures, processes, and transports lipids and proteins. The Golgi apparatus processes and packages proteins.

lysosome

breaks down macromolecules using digestive enzymes

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

cell wall The cell wall is a rigid supporting structure.

The contractile vacuole __________.

eliminates excess water from the cytoplasm of freshwater protists It keeps the freshwater protists in osmotic balance.

Which of the following is NOT a part of the endomembrane system?

mitochondria Mitochondria are involved in energy processing and are not members of the endomembrane system.

Which of these organelles carries out cellular respiration?

mitochondrion Mitochondria convert the chemical energy of organic molecules to chemical energy in the form of ATP.

Digestive cells produce and secrete many enzymes that break down ingested food. These cells have a large number of ribosomes __________.

on the rough endoplasmic reticulum The rough endoplasmic reticulum is responsible for producing proteins that will be inserted into membranes, packaged in certain organelles, or exported from the cell.

Polypeptides are assembled from _____.

amino acids

Which technique allowed scientists to figure out that all cells, and not just muscle cells, contained actin filaments?

electron microscopy In the 1960s, staining actin filaments and visualizing them with an electron microscope allowed scientists to discover that these structures are present in all cells.

What changes would you expect to see in the liver cells of someone suffering from chronic alcoholism?

increased levels of endoplasmic reticulum activity The smooth endoplasmic reticulum of liver cells has enzymes that are involved in alcohol metabolism. This organelle is affected in the liver cells of alcoholics.

Bacterial cells are prokaryotic; unlike a typical eukaryotic cell, they _____.

lack a nucleus The term prokaryotic literally translates as "before nucleus."

The internal skeleton of a cell is composed of _____.

microtubules, intermediate filaments, and microfilaments These three types of fibers make up the cytoskeleton.

Where in a cell is ATP made?

mitochondria

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

plasma membrane

Which of the following clues would tell you whether a cell is prokaryotic or eukaryotic?

whether or not the cell is partitioned into compartments by internal membranes Prokaryotic cells lack any internal membranous compartmentalization whereas eukaryotic cells have membrane-bound organelles.