Biology Review: Best of Chapter 04 Homework

Mitochondrion

-harvests chemical energy from food -produces CO2 as a waste product -found in both animal cells and plant cells -organelle of cellular respiration Mitochondria and chloroplasts are organelles that perform vital functions in living cells. Mitochondria in plant cells and animal cells help convert chemical energy from sugar into ATP that the cell can more easily use. This process is called cellular respiration.

1 meter = _____ centimeters.

100 centimeters A centimeter is 1 hundredth of a meter.

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.

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

D The nucleoid region contains DNA.

.................... is the self-replicating material present in nearly all living organisms; it is the main constituent of chromosomes and the carrier of genetic information.

DNA

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

Fimbriae Fimbriae enable bacterial cells to stick to a surface.

____ 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.

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.

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.

................... is used in all steps of protein synthesis and carries the genetic information of many viruses.

RNA

What do the rough endoplasmic reticulum, Golgi apparatus, and lysosomes have in common?

They are constructed of interrelated membranes. Each of these organelles is a member of the endomembrane system and is constructed of the same type of membrane.

Mitochondria are found in _____.

both plant and animal cells Mitochondria are found in nearly all eukaryotic cells.

The structural framework in a cell is the

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

The primary role of _____ is to bind animal cells together

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

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.

The plant cell wall

is a protective structure made of cellulose fibrils. The cell wall is a structure that protects the plant cell and is made of cellulose fibrils.

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

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

Mitochondria appear in the greatest numbers in cells that are _____.

metabolically active Mitochondria are the sites of cellular respiration, the catabolic process that generates ATP by extracting energy from food molecules, with the help of oxygen.

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

microtubules Eukaryotic cilia and flagella are composed of microtubules.

The ......................... is the two-layered membrane that encases the nucleus of a eukaryotic cell, separating the nucleus from the cytoplasm.

nuclear envelope

Where is a bacterial cell's DNA found?

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

The round body that sits inside the nucleus of a eukaryotic cell and makes ribosomal subunits from proteins and ribosomal RNA is known as the.................

nucleolus

The ....................... is the most prominent membrane-bound organelle in eukaryotic cells, and it houses most of a cell's DNA.

nucleus

Where is the genetic information of the cell stored?

nucleus DNA is the genetic information of the cell, and it is stored in the nucleus.

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

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

In plants, __________ are the cell junctions that allow the free exchange of small molecules that assist in communication. In animal cells, similar cell junctions are known as __________.

plasmodesmata ... gap junctions Plant cells are interconnected by plasmodesmata, which form tubelike structures that penetrate through the cell walls. Gap junctions are formed by specialized channels found in animal cells. Both Plamodesmata and gap junctions allow the free exchange of small molecules and help coordinate the activities of neighboring cells.

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.

In a bacterium, where are proteins synthesized?

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

Where are lipids made in the cell?

smooth endoplasmic reticulum (ER) The smooth ER makes lipids.

Lysosomes are derived from __________ and function in __________.

the Golgi apparatus and rough endoplasmic reticulum ... digestion of worn-out organelles Lysosomes are membrane-enclosed sacs of hydrolytic enzymes that are used to digest macromolecules. They are produced by budding off the Golgi apparatus.

Which plant cell organelle converts chemical fuel into packets of chemical energy that can power the cell?

Mitochondrion. In both plant and animal cells, it's the mitochondria that convert chemical fuel into packets of chemical energy that can power the cell.

Where in a cell is ATP made?

mitochondria ATP is made in mitochondria.

A protein-lined channel in the nuclear envelope that regulates the transportation of molecules between the nucleus and the cytoplasm is called a ......................

nuclear pore

Chloroplast

-organelle of photosynthesis -produces O2 as a waste product -found only in plant cells and some algae -converts solar energy to chemical energy -contains thylakoids Chloroplasts are found only in the cells of plants and some algae. Chloroplasts help turn sunlight into sugar in a process called photosynthesis. The sugars generated in photosynthesis can be used by the plant itself during its own cellular respiration, or by animals that eat the plant.

Which of the following is a function of the central vacuole?

Storing compounds produced by the cell One of the functions of the central vacuole is to store compounds produced by the cell.

Which of the following describes the function of the chloroplast?

The chloroplast converts light energy to chemical energy. The chloroplast makes food for the plant cell by converting light energy to chemical energy.

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.

Flagella and cilia are both composed of tubulin subunits. Despite this similarity, key differences exist between these two structures. For example, __________.

only cilia move as a coordinated team Cilia work together in a coordinated team, much like the oars on a rowing team. This allows them to propel fluids along their surfaces for locomotion or feeding.

What is the function of a bacterium's capsule?

protection A bacterium's capsule has a protective role.

You would expect a cell with an extensive Golgi apparatus to _____.

secrete a lot of material The Golgi apparatus intercepts ER vesicles, modifies the contents for export, and repackages the material in a Golgi vesicle that can fuse with the plasma membrane.

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

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

__________ is the most prevalent glycoprotein in the extracellular matrix

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

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

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

Which of the following is part of the endomembrane system?

Golgi apparatus 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.

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

_____ are found only in plant cells, but _____ are found in both plant and animal cells.

Central vacuoles are found only in plant cells. Ribosomes are found in both plant and animal cells.

A 100 mm x 100 mm x 100 mm cell has a surface area that is _____ and a volume that is _____. When this volume is broken into many smaller cells, that are 10 mm x 10 mm x 10 mm, the sum of the surface areas of the smaller cells is _____ than the surface area of the initial cell.

60,000 mm2 ... 1,000,000 mm3 ... larger The smaller cell has a larger surface (600 mm2) to volume (1,000 mm3) ratio. This accounts for why most cells are microscopic.

......................... are tightly coiled bundles of DNA and protein found in the nucleus of most living cells.

Chromosomes

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.

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

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

Of the following organelles, which group is involved in manufacturing the substances needed by the cell?

ribosome, rough endoplasmic reticulum, smooth endoplasmic reticulum Each structure is capable of synthesis.

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.