Chapter 4 Smartbook

Identify the three parts of the cell theory.

1. Cells are the smallest units

2. All living organisms are composed of one or more cells

3. New cells come only from pre-existing cells by cell division

In terms of cell size, the majority of cells are:

too small to be seen with the unaided eye

A magnification tool that enables researchers to study the structure and function of cells is the .

microscope

Resolution is the ability of a microscope to do which of the following?

Accurately distinguish between two separate entites

The ratio between the size of an image of an object produced by a microscope and its actual size is called

Magnification

Which of these statements is not a part of the cell theory?

All living organisms are composed of one or more cells.

All cells are replaced.

New cells come only from pre-existing cells by cell division.

Cells are the smallest units of life.

All cells are replaced.

Microscopes can be divided into two main categories based on the source of

Illumination

Most cells are visible to the naked eye.

false

Which of these is an optical instrument that allows researchers to view and study very small objects, such as cellular structures?

Microscope

Compared to a light microscope, the resolution of an electron microscope is about ______ times better.

100

The ability to observe two adjacent objects as distinct from one another, a measure of clarity, is called

resolution

What parameter of an optical instrument refers to its ability to make small objects appear larger?

magnification

What are the two main types of electron microscopy?

transmission electron microscopy and scanning electron microscopy

A light microscope utilizes _ for illumination, whereas an electron microscope uses a beam of _

light, electrons

In order to visualize the fine structure of viruses and cytoskeletal filaments at 10–25 nanometers in diameter, the type of microscopy that would be most effective is ______.

transmission electron microscopy

In terms of cell size, the majority of cells are:

too small to be seen with the unaided eye

To produce a detailed image of the three-dimensional surface of a sample, a biologist would use _ _ microscopy

scanning electron

What is the resolution of a very good light microscope?

about 0.2 μm

Resolution is the ability of a microscope to do _

Accurately distinguish between two separate entities

What do prokaryotes lack?

membrane-enclosed nucleus

Two general types of electron microscopy have been developed: electron microscopy and electron microscopy

transmission, scanning

Most bacteria are able to cause disease.

false

Which type of microscopy is used to provide high resolution of a cross-sectional view of a cell?

transmission electron microscopy

What is the phospholipid bilayer barrier between the cell and its external environment called?

plasma membrane

In scanning electron microscopy, the sample is coated with a thin layer of _ _, such as gold or palladium, and is then exposed to an electron beam that scans its surface

heavy metal

The area of the cell that is surrounded by the plasma membrane is called the ______.

cytoplasm

The wavelength of an electron is than visible light. Thus, the resolution of an electron microscope is  than that of a light microscope

shorter, better

In bacteria, the genetic material is located in a region of the cytoplasm called the

nucleoid

Prokaryotes differ from eukaryotes because they lack a membrane-enclosed _, which houses the DNA

nucleus

Structures found in both prokaryotic and eukaryotic cells that are the sites of polypeptide synthesis are called

ribosomes

The prokaryotes that are abundant throughout the world in soil, water, and the human digestive tract are called _. While also common, the prokaryotes that are typically found in more extreme environments such as hot springs and deep-sea thermal vents are called _.

bacteria, archaea

A phospholipid bilayer that forms a barrier between a cell and its external environment is the plasma _

membrane

Label the parts of the bacterial cell: I = _, II = _, III = _

Nucleoid, Plasma Membrnae, Cell wall

In a bacterial cell, the region of the cell contained within the plasma membrane is called the

cytoplasm

Nearly all species of archaea and bacteria have rigid _ _ that supports and protects the plasma membrane and cytoplasm.

cell wall

Where is the DNA housed in a bacterial cell?

Nucleoid Region

What structure functions in polypeptide synthesis?

Ribosome

Appendages used by prokaryotic cells to move are called

flagella

Most bacteria are able to cause disease.

False

Aside from bacteria and archaea, all other species are

eukaryotes

X = _

glycocalyx

Describe the cell walls of most bacteria and archaea

rigid

Where is most of the DNA located in a eukaryotic cell?

Nucleus

In bacteria, the genetic material is located in a region of the cytoplasm called the _

nucleoid

Describe an organelle

A membrane-bound component with its own unique structure and function

What is used by prokaryotes to move?

Flagella

Which of the following organisms are eukaryotes?

Archaea

Plants

Fungi

Animals

Bacteria

Plants, fungi, animals

What cells have membrane-bound organelles to compartmentalize functions?

Eukaryotic cells only

A = Rough ER, B = Mitochondrian, C= Cytoskeleton, D = Nucelolus, E = Ribosome

In eukaryotic cells, most of the DNA is housed in an internal compartment, or organelle, called the _

nucleus

Plant cells and animal cells have similar organelles. However, plants cells have unique structures including chloroplasts, a central _ and a cell _

vacuole, wall

The general term used to describe a membrane-bound structure within a cell that has its own unique structure and function is _

organelle

I = Nucleolus, II = Chloroplast, III = Cell Wall, IV = cytosol

Appendages used by prokaryotic cells to move are called __.

flagella

Which of the following is the best reason for cells being small?

Multiple choice question.

The cell membrane can only stretch so much and so cannot accommodate the larger size.

Larger cells would create too much heat and enzymes will denature.

Larger cells would not be able to get necessary gases and nutrients quickly enough.

Larger cells would require more nutrients and there is usually a limited supply.

Larger cells would not be able to get necessary gases and nutrients quickly enough.

Eukaryotic cells have many membrane-bound compartments called _, whereas prokaryotic cells do not exhibit compartmentalization.

organelles

A low surface area-to-volume ratio enables cells to take up nutrients and eliminate wastes efficiently.

False

I = Nucleus, II = Centrosome, III = Mitochondrion, IV = Golgi apparatus, V = Plasma membrane

Plant and animal cells have identical internal organelles and structures.

False

As the radius of a cell gets larger, the SA/V ratio _.

gets smaller

What term describes the region of a eukaryotic cell that is outside the membrane-bound organelles but inside the plasma membrane?

Cytosol

The size of a metabolizing cell is limited by:

its surface area-to-volume ratio.

In order to take up nutrients and export wastes efficiently, a cell's surface area-to-volume ratio should be ______.

high

The region that is enclosed by the plasma membrane but outside the organelles is called the _. It is the location of chemical reactions by which cells produce the materials and utilize the energy necessary to sustain life.

cytosol

What type of cell would have the hardest time exporting waste?

large and round

The region of a eukaryotic cell that is outside the membrane-bound organelles but inside the plasma membrane is the

cytosol

Three different types of protein filaments that make up the cytoskeleton.

Microtubules, intermediate filaments, actin filaments

Microtubules are cytoskeletal structures composed of which protein?

Tubulin

Most cells are small because the ability to exchange nutrients and wastes is limited by the surface _ to _ratio.

area, volume

Within the centrosome, there is a pair of structures arranged perpendicular to each other called the

centrioles

The functions of microtubules include ______

moving chromosomes during mitosis and maintaining cell shape and organization

A structure that has a staggered alignment of different proteins such as keratin and lamin and may be found in such places as skin and kidney cells is called a(n) _ filament.

intermediate

As the radius of a cell gets larger, the SA/V ratio Blank______.

gets smaller

Long, hollow, cylindrical structures about 25 nm in diameter and composed of the protein tubulin are called

microtubules

Nondividing animal cells contain a single structure near their nucleus called the _

centrosome

What are the thinnest cytoskeletal filaments (7nm)

Actin filaments

What cytoskeletal filaments are responsible for moving chromosomes during mitosis and for organizing the cell's organelles?

microtubules

The class of proteins that use ATP as a source of energy to promote various types of movements is called

motor

Describe intermediate filaments

Twisted filament that can be composed of keratin or lamin

Cilia and flagella are two types of cell appendages that use which of these to facilitate movement?

Microtubules and motor proteins

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

Endoplasmic reticulum

Mitochondrion

Lysosome

Golgi apparatus

Nuclear envelope

Mitochondrion

Microfilaments is another name for

actin filaments

The nucleus is enclosed by a double membrane structure called the _

Nuclear envelope

The protection and organization of the genetic material of the cell are the primary functions of the _

nucleus

Where does the assembly of ribosome subunits occur?

nucleolus

How many subunits make up a ribosome?

Two: one large and one small

What is the double membrane structure that surrounds the nucleus called?

Nuclear envelope

The membranes of the endoplasmic reticulum form which of the following?

Cisternae, fluid-filled tubules

What are major functions of the nucleus?

Gene regulation and protecting the genome

The ER membrane encloses a single compartment called the ER

lumen

What is the function of the rough endoplasmic reticulum?

Sorting proteins destined for other locations

The smooth ER is _ with the rough ER

continuous

Glycosylation

Process of covalently attaching a carbohydrate to a protein or a lipid

What organelle synthesizes lipids, stores calcium ions, and detoxifies harmful organic molecules?

Smooth ER

What organelle in liver cells produces enzymes that detoxify harmful organic molecules?

Smooth ER

In animals, carbohydrates are stored in _ granules adjacent to the smooth ER membrane in liver cells. These release energy upon demand.

glycogen

Enzymes in the smooth ER are involved in the synthesis and modification of ______.

lipids

What are the functions of the smooth endoplasmic reticulum?

storage of calcium ions, detoxification of harmful organic molecules, synthesis and modification of lipids

Describe the structure of the golgi apparatus

A stack of flattened membranes, each enclosing a single compartment

Overlapping functions of the golgi apparatus

Protein processing, secretion, sorting