Chapter 4 Cell Structure Study Set

Plasmodesmata are channels between

adjacent plant cells

Plasma cells are cells of the immune system committed to production of large amounts of protein (antibodies) for export. These cells would be expected to contain

an extensive network of rough endoplasmic reticulum.

microscope

an instrument that magnifies an object

light microscope

an instrument that magnifies an object using a beam visible light passed and bent through a lens system to visualize a specimen

gap junctions

are channels between adjacent animal cells.

nucleus

cell organelle that houses the cell's DNA and directs the synthesis of ribosomes and proteins

nucleoid

central part of a prokaryotic cell in which the chromosome is found

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

central vacuole

gap junction

channel between two adjacent animal cells that allows ions, nutrients, and low molecular weight substances to pass between cells, enabling the cells to communicate

If plant cells are grown on media containing radioactively labeled thymine for one generation, radioactively labeled macromolecules will be detected in which of the following?

in the nucleus, mitochondria, and chloroplasts

flagellum (plural = flagella)

long, hair-like structure that extends from the plasma membrane and is used to move the cell

What cellular structures provide protection from toxic materials?

peroxisomes

Which cell would be best for studying lysosomes?

phagocytic white blood cell

Which structure is common to all three domains of life?

phospholipid bilayer cell membrane

rough endoplasmic reticulum (RER)

region of the endoplasmic reticulum that is studded with ribosomes and engages in protein modification and phospholipid synthesis

The SER does what?

synthesizes carbohydrates, lipids, and steroid hormones; engages in the detoxification of medications and poisons; and stores calcium ions.

Intermediate filaments bear

tension and anchor the nucleus and other organelles in place.

Lysosomes are created by

the budding of the membranes of the RER and Golgi.

When protein receptors on the surface of the plasma membrane of an animal cell bind

to a substance in the extracellular matrix, a chain of reactions begins that changes activities taking place within the cell.

What is a primary function of integrins?

transmitting signals from the extracellular matrix to the cytoskeleton

The cytoskeleton has three different types

of protein elements.

What best differentiates a fungal cell from a bacterial cell?

All cells have proteins embedded in their membranes, and although the specific proteins might vary between the two groups, they also have a lot in common. While the composition of the cell walls of both groups vary, the presence of the cell wall does not differentiate them. Both groups can metabolize some toxic materials to some extent or another. While fungi always lack photosynthetic pigments, only a few bacterial groups possess them. When it comes to the presence of a nucleus, all fungi are eukaryotic, while all bacteria are prokaryotic.

Which structure below is independent of the endomembrane system? A) nuclear envelope B) chloroplast C) Golgi apparatus D) plasma membrane

B) chloroplast

Which of the following are found in plant, animal, and bacterial cells? A) mitochondria B) ribosomes C) chloroplasts D) endoplasmic reticulum

B) ribosomes

Which structure is common to plant and animal cells?

C) mitochondrion

Cytochalasin D is a drug that prevents actin polymerization. A cell treated with cytochalasin D will still be able to carry out which of the following processes? A) divide in two B) contract muscle fibers C) extend pseudopodia D) move vesicles within a cell

D) move vesicles within a cell

Which of the following products can be found in vacuoles? A. water B. sugars C. water-soluble pigments D. all of these are found in vacuoles

D. all of these are found in vacuoles

Which statement is true of animal cells but not plant cells? (A) During cytokinesis, a cleavage furrow forms between the two dividing cells. (B) Several mitochondria are present for cellular respiration. (C) Several chloroplasts are present for photosynthesis. (D) Animal cells lack a nuclear envelope.

During cytokinesis, a cleavage furrow forms between the two dividing cells.

A newly discovered unicellular organism isolated from acidic mine drainage is found to contain a cell wall, a plasma membrane, two flagella, and peroxisomes. Based just on this information, the organism is most likely ________. A) a nonmotile prokaryote B) a motile bacterium C) a motile archaea D) a nonmotile eukaryote E) a motile eukaryote

E) a motile eukaryote

All cells have a cell wall that regulates the passage of molecules into and out of the cell. T or F?

F. All cells have a plasma membrane (not cell wall) that regulates the passage of molecules into and out of the cell.

After proteins are formed by the ribosomes located on the endoplasmic reticulum, what is the next organelle to which they could be transported?

Golgi Apparatus

What organelle produces and modifies polysaccharides that will be secreted?

Golgi Apparatus

Which of the following gives rise to both lysosomes and vesicles?

Golgi apparatus

Which of the following gives rise to both lysosomes and vesicles? A. rough endoplasmic reticulum B. mitochondria C. Golgi apparatus D. ribosomes

Golgi apparatus

A mutation that disrupts the ability of an animal cell to add polysaccharide modifications to proteins would most likely cause defects in what organelles or structures?

Golgi apparatus and extracellular matrix

Where are proteins produced other than on ribosomes free in the cytosol or ribosomes attached to the endoplasmic reticulum?

In Mitochondria

Asbestos is a material that was once used extensively in construction. One risk from working in a building that contains asbestos is the development of asbestosis caused by the inhalation of asbestos fibers. Cells will take up asbestos by phagocytosis, but are not able to degrade it. As a result, asbestos fibers accumulate in ________.

Lysosomes

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

Which is true about bacteria?

Some are photosynthetic. Some are motile due to flagella. All bacteria are prokaryotes. Bacteria have a cell wall that contains peptidoglycan.

What statements is true about bacterial anatomy?

The cell wall is located outside of the plasma membrane. There may be small rings of accessory DNA called plasmids. Bacteria may have fimbriae that help attach the bacteria to other structures.

What organelle would be found in increased quantities in the liver cells of a person who abuses alcohol and / or other drugs on a regular basis?

The smooth endoplasmic reticulum is associated with detoxification, and would, therefore, be found in increased quantities of an alcohol or drug abuser.

What are the potential consequences of an individual who suffers from a genetic disorder that prohibits them from properly forming microtubules ?

Their cells will not be able to maintain the normal cellular shape. The cells may not be able to divide correctly during cellular division. The cilia located on the respiratory cells may have a limited function.

The ribosome is best associated with what process?

Translation

Cilia and flagella bend because of ________.

a motor protein called dynein

Spherocytosis is a human blood disorder associated with a defective cytoskeletal protein in the red blood cells (RBCs). What do you suspect is the consequence of such a defect?

abnormally shaped RBCs

mitochondria (singular = mitochondrion)

cellular organelles responsible for carrying out cellular respiration, resulting in the production of ATP, the cell's main energy-carrying molecule

ribosome

cellular structure that carries out protein synthesis

plasmodesma (plural = plasmodesmata)

channel that passes between the cell walls of adjacent plant cells, connects their cytoplasm, and allows materials to be transported from cell to cell

In a liver cell detoxifying alcohol and some other poisons, the enzymes of the peroxisome remove hydrogen from these molecules and ________.

combine the hydrogen with oxygen molecules to generate hydrogen peroxide

organelle

compartment or sac within a cell

nuclear envelope

double-membrane structure that constitutes the outermost portion of the nucleus

If you were using compartment-specific stains and found that a stain for the nuclear envelope lightly stained another compartment as well, what would that other compartment be?

endoplasmic reticulum

The evolution of eukaryotic cells most likely involved ________.

endosymbiosis of an oxygen-using bacterium in a larger bacterial host cell-the endosymbiont evolved into mitochondria

cytoplasm

entire region between the plasma membrane and the nuclear envelope, consisting of organelles suspended in the gel-like cytosol, the cytoskeleton, and various chemicals

Vesicular transport is utilized by

eukaryotic cells to move substances from the Golgi appararus to other areas of the cell following a microtubule framework. Substances entering or leaving the nucleus must be escorted through nuclear pores by specific escort proteins

You are a linear DNA molecule complexed with protein. You reside within a nuclear envelope. You are a prokaryotic chromosome or a eukaryotic chromosome.

eukaryotic chromosome.

Golgi apparatus

eukaryotic organelle made up of a series of stacked membranes that sorts, tags, and packages lipids and proteins for distribution

tight junction

firm seal between two adjacent animal cells created by protein adherence

Ions can travel directly from the cytoplasm of one animal cell to the cytoplasm of an adjacent cell through ________.

gap junctions

Materials pass in and out of a nucleus by a process called

gated transport.

cytosol

gel-like material of the cytoplasm in which cell structures are suspended

In plant cells, the middle lamella ________.

glues adjacent cells together

chlorophyll

green pigment that captures the light energy that drives the light reactions of photosynthesis

Without a cytoskeleton, eukaryotic cells would NOT

have an efficient way to transport materials from one organelle to another.

central vacuole

large plant cell organelle that regulates the cell's storage compartment, holds water, and plays a significant role in cell growth as the site of macromolecule degradation

During the sequencing of DNA into a protein, what is the first step?

mRNA is copied from a gene

According to the endosymbiosis theory _______ were engulfed by larger eukaryotic cells.

mitochondria

Cyanide binds with at least one molecule involved in producing ATP. If a cell is exposed to cyanide, most of the bound cyanide is likely to be localized within the ________.

mitochondria

Cyanide binds to at least one molecule involved in producing ATP. If a cell is exposed to cyanide, most of the cyanide will be found within the

mitochondria.

The RER does what?

modifies proteins and synthesizes phospholipids used in cell membranes.

Researchers investigating the mechanism of vesicular transport assembled a cell-free system that included microtubule tracks, vesicles, and ATP. However, they observed no movement of transport of vesicles in this system. What were they missing?

motor proteins

Movement of cilia and flagella is the result of

motor proteins causing microtubules to move relative to each other.

A large plant cell will have proportionally a large amount of which protein?

myosin

microfilament

narrowest element of the cytoskeleton system; it provides rigidity and shape to the cell and enables cellular movements

Chloroplasts are to ____________ as ___________ are to aerobic respiration.

photosynthesis, mitochondria

chloroplast

plant cell organelle that carries out photosynthesis

What structures form cytoplasmic channels that connect adjacent plant cells through the cell walls?

plasmodesmata

Plant cells are connected and communicate with each other via

plasmodesmata.

What do plant cells have that no other cells have?

plastids

A cell with a predominance of rough endoplasmic reticulum is most likely ________.

producing large quantities of proteins for secretion

The plant cell wall, whose primary component is cellulose, does what

protects the cell, provides structural support, and gives shape to the cell. Photosynthesis takes place in chloroplasts. The central vacuole can expand without having to produce more cytoplasm.

cell wall

rigid cell covering made of cellulose that protects the cell, provides structural support, and gives shape to the cell

Microfilaments provide

rigidity and shape to the cell and facilitate cellular movements.

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

rough ER → Golgi → transport vesicle → plasma membrane

nucleoplasm

semi-solid fluid inside the nucleus that contains the chromatin and nucleolus

endoplasmic reticulum (ER)

series of interconnected membranous structures within eukaryotic cells that collectively modify proteins and synthesize lipids

In bacteria, DNA will be found in ________.

the nucleoid

Animal cells communicate via

their extracellular matrices and are connected to each other via tight junctions, desmosomes, and gap junctions.

From narrowest to widest what are the protein elements

they are the microfilaments (actin filaments), intermediate filaments, and microtubules.

The detailed structure of a chloroplast can be seen with the best resolution by using ___________ microscopy.

transmission electron

Cells require what to form cilia or flagella?

tubulin

prokaryote

unicellular organism that lacks a nucleus or any other membrane-bound organelle

microtubule

widest element of the cytoskeleton system; it helps the cell resist compression, provides a track along which vesicles move through the cell, pulls replicated chromosomes to opposite ends of a dividing cell, and is the structural element of centrioles, flagella, and cilia

What is the difference between tight junction and a desmosome?

However, their structures are quite different. A tight junction is a watertight seal between two adjacent cells, while a desmosome acts like a spot weld.

vesicle

small, membrane-bound sac that functions in cellular storage and transport; its membrane is capable of fusing with the plasma membrane and the membranes of the endoplasmic reticulum and Golgi apparatus

peroxisome

small, round organelle that contains hydrogen peroxide, oxidizes fatty acids and amino acids, and detoxifies many poisons

The endomembrane system includes what and what do they do?

the nuclear envelope, lysosomes, vesicles, the ER, and Golgi apparatus, as well as the plasma membrane. These cellular components work together to modify, package, tag, and transport proteins and lipids that form the membranes.

A eukaryotic cell carries out phagocytosis and engulfs a bacterial cell, which ends up in the resulting food vacuole. To go from the cytosol of this bacterial cell to outside of the eukaryotic cell that has taken it in, what is the least number of biological membranes that would have to be crossed?

3

4.1 Studying Cells

A cell is the smallest unit of life. Most cells are so tiny that they cannot be seen with the naked eye. Therefore, scientists use microscopes to study cells. Electron microscopes provide higher magnification, higher resolution, and more detail than light microscopes. The unified cell theory states that all organisms are composed of one or more cells, the cell is the basic unit of life, and new cells arise from existing cells.

Which is NOT a characteristic of mitochondria? A. A mitochondrion has two membranes. B. Mitochondria are the site of cellular respiration. C. Mitochondria have a single membrane for cellular respiration. D. Mitochondria contain DNA and ribosomes. E. The inner space of the mitochondrion contains a fluid matrix.

C Mitochondria have a double membrane.

11) Which of the following is a major difference between prokaryotic cells and eukaryotic cells? A) Prokaryotic cells have cell walls, while eukaryotic cells do not. B) Eukaryotic cells have flagella, while prokaryotic cells do not. C) Eukaryotic cells have membrane-bound organelles, while prokaryotic cells do not. D) Prokaryotic cells are generally larger than eukaryotic cells.

C) Eukaryotic cells have membrane-bound organelles, while prokaryotic cells do not.

Which of the following frequently imposes a limit on cell size? A) the absence of a nucleus B) the number of mitochondria in the cytoplasm C) ratios of surface area to volume D) the volume of the endomembrane system

C) ratios of surface area to volume

Which of the following is NOT offered as evidence in support of the endosymbiotic theory, the belief that a eukaryotic cell has evolved as a "committee" of prokaryotic cells? A. Mitochondria and chloroplasts are similar in size and structure to some species of bacteria. B. The ribosomes of chloroplasts and mitochondria are similar to bacteria. C. Mitochondria and chloroplasts can actively break away from eukaryotic cells and live on their own. D. Mitochondria and chloroplasts have their own DNA coding separate from the eukaryotic nucleus. E. All of the choices offer support of the endosymbiotic theory.

C. Mitochondria and chloroplasts can actively break away from eukaryotic cells and live on their own.

Which is a true statement about ribosomes? A. Ribosomes contain DNA and protein. B. Ribosomes are active in carbohydrate synthesis. C. Ribosomal subunits leave the nucleus after being formed by the nucleolus. D. Polyribosomes are the subunits of ribosomes. E. Ribosomes are only found associated with the endoplasmic reticulum in prokaryotic cells.

C. Ribosomal subunits leave the nucleus after being formed by the nucleolus.

Which is NOT true of eukaryotic cells? A. A true nucleus contains the chromosomes. B. Eukaryotic cells contain membrane-bounded compartments. C. They contain ribosomes that are smaller than those of prokaryotic cells. D. They all contain mitochondria. E. They contain many organelles in the cytoplasm.

C. They contain ribosomes that are smaller than those of prokaryotic cells.

Which cytoskeletal element is NOT correctly associated with its characteristic? A. Cilia are small extensions of membrane-surrounded microtubules. B. Microtubules are made up of a globular protein called tubulin. C. Centrioles are found in the microtubule organizing centers of plants. D. Flagella have a 9 + 2 pattern of microtubule structure. E. Basal bodies are located at the base of cilia and flagella.

Centrioles are found in the microtubule organizing centers of plants.

The springtail is a very common small insect that lives in rotten logs, rich soil, and other humid places. Its cuticle is water repelling (hydrophobic) except for a strange organ, the collophore, on its ventral side. Because it lacks the excretory organs of other insects, the springtail has this organ in contact with the water (it is responsible for ion balance and secretion of wastes). If we examined the cell structure of this collophore, we would expect to find a high number of

Golgi bodies.

Which is NOT true about the cell theory? A. Its various parts were described by Schleiden, Schwann, and Virchow. B. It states that all organisms are composed of cells. C. It states that all cells come from preexisting cells. D. It states that bacteria and other small organisms can arise spontaneously. E. It is accepted today by biologists as applying to virtually all forms of life.

It is accepted today by biologists as applying to virtually all forms of life.

What is the function of the nuclear pore complex found in eukaryotes?

It regulates the movement of proteins and RNAs into and out of the nucleus.

_______ are to ribosomes as lipids are to _________.

Proteins; smooth endoplasmic reticulum. Proteins are synthesized by ribosomes and lipids are made in the smooth endoplasmic reticulum.

During cellular movement which of the following filaments will be the ones that are responsible for attaching and pulling the other filaments along?

The motor molecule myosin is responsible for pulling the actin filament along.

DNA is housed within the nucleus, but the mRNA code needs to leave in order to be translated into a protein. How does the mRNA code leave the nucleus if the nucleus is surrounded by the nuclear envelope?

The nuclear envelope contains pores that allow the mRNA to exit through.

Which statement about the nucleus is incorrect? A. The nucleus contains the genetic material of the cell. B. The nucleus contains the information that ribosomes use to carry out protein synthesis. C. The nucleus contains the instructions for copying itself. D. The nucleus contains the information that ribosomes use to carry out cellular respiration.

The nucleus contains the information that ribosomes use to carry out cellular respiration.

The cell walls of bacteria, fungi, and plant cells, and the extracellular matrix of animal cells are all external to the plasma membrane. What characteristics are common to all of these extracellular structures?

They are constructed of materials that are synthesized in the cytoplasm and then transported out of the cell for assembly.

Mitochondria and chloroplasts are able to reproduce independently from the division of the cell.

True

Mitochondria are thought to be derived from aerobic bacteria that became part of the eukaryotic cell through endosymbiosis. T or F?

True

DNA can be found in

a cell nucleus and a mitochondrion.

If a researcher was interested in slowing down the movement of amoebas by disrupting their cell membranes, which protein filaments should she be studying?

actin Actin filaments are found in the cell membrane of amoebas that help facilitate movement.

Lysosomes

are the digestive organelles of animal cells.

Thylakoids, DNA, and ribosomes are all components found in ________.

chloroplasts

Stroma is found in

chloroplasts.

Motor proteins provide for molecular motion in cells by interacting with what types of cellular structures?

components of the cytoskeleton

intermediate filament

cytoskeletal component, composed of several intertwined strands of fibrous protein, that bears tension, supports cell-cell junctions, and anchors cells to extracellular structures

nucleolus

darkly staining body within the nucleus that is responsible for assembling the subunits of the ribosomes

A characteristic 9 + 2 arrangement of microtubules, consisting of nine doublets of microtubules surrounding a pair of single microtubules is associated with ________.

eukaryotic flagella and motile cilia

Amoebae move by crawling over a surface (cell crawling), which involves ________.

growth of actin filaments to form bulges in the plasma membrane

All cells have these two characteristics:

have a plasma membrane and ribosomes in the cytoplasm

Each time the water in a cell freezes slowly, long sharp crystals spear through the membrane structures of the cell. However, in the frozen state, virtually no chemical reactions occur. The most likely explanation for the bad taste of meat that has "freezer burn" from repeated freezing is the destruction of

lysosomes and resultant autodigestion.

Which of the following macromolecules leave the nucleus of a eukaryotic cell through pores in the nuclear membrane? A) DNA B) amino acids C) mRNA D) phospholipids

mRNA

Lysosomes digests

macromolecules, recycle worn-out organelles, and destroy pathogens.

Microfilaments are often associated with

myosin.

cytoskeleton

network of protein fibers that collectively maintain the shape of the cell, secure some organelles in specific positions, allow cytoplasm and vesicles to move within the cell, and enable unicellular organisms to move independently

Which of the following features is unique to bacterial cells?

nucleoid region

What cellular organelle is the most prominent?

nucleus

Which of the following features is NOT found in a bacterial cell?

nucleus

Most bacteria live in a solution that is hypotonic relative to the cytoplasm of the bacteria. The cell wall of a bacterium is a peptidoglycan polymer that is tightly cross-linked. This would therefore function to

provide a rigid wall that prevents the cell from swelling.

The plant cell's central vacuole

provides the plant cell with support, stores nutrients and cellular waste products, is a reservoir for water.

centrosome

region in animal cells made of two centrioles

smooth endoplasmic reticulum (SER)

region of the endoplasmic reticulum that has few or no ribosomes on its cytoplasmic surface and synthesizes carbohydrates, lipids, and steroid hormones; detoxifies certain chemicals (like pesticides, preservatives, medications, and environmental pollutants), and stores calcium ions

Microtubules help the cell

resist compression, serve as tracks for motor proteins that move vesicles through the cell, and pull replicated chromosomes to opposite ends of a dividing cell. They are also the structural element of centrioles, flagella, and cilia.

Which of the following macromolecules enter the nucleus of a eukaryotic cell through pores in the nuclear membrane? A) ribosomal proteins B) mRNA C) rRNA D) phospholipids

ribosomal proteins

What cellular organelle is responsible for receiving the mRNA and turning it into a protein?

ribosome

Which of the following is present in a prokaryotic cell? A) mitochondrion B) ribosome C) nuclear envelope D) chloroplast

ribosome

Which cellular structure is present in all cells?

ribosomes

Vinblastine, a drug that inhibits microtubule polymerization, is used to treat some forms of cancer. Cancer cells given vinblastine would be unable to ________.

separate chromosomes during cell division

cilium (plural = cilia)

short, hair-like structure that extends from the plasma membrane in large numbers and is used to move an entire cell or move substances along the outer surface of the cell

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 is most likely defective in this condition?

the lysosome

A multicellular organism like a rabbit will be

Composed of a variety of different cell types.

Which of the following help direct the movement of materials or organelles throughout the cell? A. rough endoplasmic reticulum B. cytoskeleton C. smooth endoplasmic reticulum D. all of the choices are true

D. all of the choices are true

Mitochondria have an inner membrane system called thylakoid membranes. T or F ?

F. The inner membrane of mitochondria are folded into cristae. Chloroplasts have thylakoid membranes.

Suppose a young boy is always tired and fatigued, suffering from a metabolic disease. Which of the following organelles is most likely malfunctioning in this disease?

Mitochondria

Suppose a cell has the following molecules and structures: enzymes, DNA, ribosomes, plasma membrane, and mitochondria. It could be a cell from ________.

Nearly every eukaryotic organism

Which organelle is primarily responsible for the breakdown of lipids within the cell?

peroxisome

Membrane-bounded vesicles that contain enzymes for oxidizing small organic molecules with the formation of hydrogen peroxide are

peroxisomes

What structures enable the vesicles from the Golgi apparatus to fuse with the cell membrane?

phospholipids Vesicles from the Golgi apparatus are made of the same phospholipid structure as the cell membrane, therefore the vesicles are able to easily fuse with the cell membrane.

the largest in size? virus, protein, mitochondria, ovum, nucleus

protein - virus - mitochondria - nucleus - ovum

A defect in which of the following intercellular junctions would allow partially digested material to leak passively between the cells of the small intestine into the abdominal cavity? A) desmosomes B) gap junctions C) plasmodesmata D) tight junctions

tight junctions

Both symport and anti port are mechanisms used by cells to

transport substances through a plasma membrane utilizing membrane-bound proteins.

electron microscope

an instrument that magnifies an object using a beam of electrons passed and bent through a lens system to visualize a specimen

eukaryotic cell

cell that has a membrane-bound nucleus and several other membrane-bound compartments or sacs

desmosome

linkages between adjacent epithelial cells that form when cadherins in the plasma membrane attach to intermediate filaments

extracellular matrix

material (primarily collagen, glycoproteins, and proteoglycans) secreted from animal cells that provides mechanical protection and anchoring for the cells in the tissue

vacuole

membrane-bound sac, somewhat larger than a vesicle, which functions in cellular storage and transport

lysosome

organelle in an animal cell that functions as the cell's digestive component; it breaks down proteins, polysaccharides, lipids, nucleic acids, and even worn-out organelles

plasma membrane

phospholipid bilayer with embedded (integral) or attached (peripheral) proteins, and separates the internal content of the cell from its surrounding environment

Which domains of life are classified as prokaryotes? A) Bacteria and Eukarya B) Bacteria and Archaea C) Archaea and Fungi D) Bacteria and Protista

B) Bacteria and Archaea

Which of the following statements correctly describes some aspect of protein secretion from prokaryotic cells? A) Prokaryotes cannot secrete proteins because they lack an endomembrane system. B) Proteins secreted by prokaryotes are likely synthesized on ribosomes bound to the cytoplasmic surface of the plasma membrane. C) The mechanism of protein secretion in prokaryotes is probably the same as that in eukaryotes. D) Prokaryotes cannot secrete proteins because they lack rough endoplasmic reticulum.

B) Proteins secreted by prokaryotes are likely synthesized on ribosomes bound to the cytoplasmic surface of the plasma membrane.

Which of the following would be the most appropriate method to observe the movements of condensed chromosomes during cell division? A) a hand lens (magnifying glass) B) standard light microscopy C) scanning electron microscopy D) transmission electron microscopy

B) standard light microscopy

Which of the following would be most appropriate method to observe the three-dimensional structure and organization of microvilli on an intestinal cell? A) a hand lens (magnifying glass) B) standard light microscopy C) scanning electron microscopy D) transmission electron microscopy

C) scanning electron microscopy

Which of the following would be most appropriate method to observe and measure the size of ribosomes in a eukaryotic cell? A) a hand lens (magnifying glass) B) standard light microscopy C) scanning electron microscopy D) transmission electron microscopy

D) transmission electron microscopy

4.3 Eukaryotic Cells

Like a prokaryotic cell, a eukaryotic cell has a plasma membrane, cytoplasm, and ribosomes, but a eukaryotic cell is typically larger than a prokaryotic cell, has a true nucleus (meaning its DNA is surrounded by a membrane), and has other membrane-bound organelles that allow for compartmentalization of functions. The plasma membrane is a phospholipid bilayer embedded with proteins. The nucleus's nucleolus is the site of ribosome assembly. Ribosomes are either found in the cytoplasm or attached to the cytoplasmic side of the plasma membrane or endoplasmic reticulum. They perform protein synthesis. Mitochondria participate in cellular respiration; they are responsible for the majority of ATP produced in the cell. Peroxisomes hydrolyze fatty acids, amino acids, and some toxins. Vesicles and vacuoles are storage and transport compartments. In plant cells, vacuoles also help break down macromolecules.

4.2 Prokaryotic Cells

Prokaryotes are predominantly single-celled organisms of the domains Bacteria and Archaea. All prokaryotes have plasma membranes, cytoplasm, ribosomes, and DNA that is not membrane-bound. Most have peptidoglycan cell walls and many have polysaccharide capsules. Prokaryotic cells range in diameter from 0.1 to 5.0 μm. As a cell increases in size, its surface area-to-volume ratio decreases. If the cell grows too large, the plasma membrane will not have sufficient surface area to support the rate of diffusion required for the increased volume.

unified cell theory

a biological concept that states that all organisms are composed of one or more cells; the cell is the basic unit of life; and new cells arise from existing cells

Plant cells and plant-like cells each have

a cell wall, chloroplasts, and a central vacuole.

Animal cells also have

a centrosome and lysosomes.

The nuclear lamina is an array of intermediate filaments that line the inner side of the nuclear membrane. If a chemical treatment caused the lamina to disassemble, what would you expect to be the most likely immediate consequence?

a change in the shape of the nucleus

endomembrane system

group of organelles and membranes in eukaryotic cells that work together modifying, packaging, and transporting lipids and proteins

The centrosome

has two bodies perpendicular to each other, the centrioles, and has an unknown purpose in cell division.

chromatin

protein-DNA complex that serves as the building material of chromosomes

Examination of a cell by transmission electron microscopy reveals a high density of ribosomes in the cytoplasm. This observation suggests that this cell is actively producing large amounts of which molecule?

proteins

chromosome

structure within the nucleus that is made up of chromatin that contains DNA, the hereditary material

A cell with a predominance of smooth endoplasmic reticulum is likely specialized to ________.

synthesize a large quantities of lipids