Chapter 4

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

Chromosomes

Mitochondrion

-found in both animal cells and plant cells -organelle of cellular respiration -harvests chemical energy from food -produces CO2 as a waste product

1 meter = _____ centimeters.

100

What is the function of a bacterium's capsule?

Protection

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 mm^2 ; 1,000,000 mm^3 ; Larger

Imagine that you fill a basketball with as many ping pong balls as possible. The volume of the basketball is __________ the total volumes of all the ping pong balls. The surface area of the basketball is __________ than the total surface areas of all the ping pong balls.

Approximately equal to ; Less than -Because the ping pong balls fit into the basketball, they have about the same volume as the basketball. However, the total surface area of all the ping balls will be much greater than the surface area of the basketball.

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

Cell wall

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

Central vacuoles ; Ribosomes

What feature of the mitochondrion enhances cellular respiration?

Cristae -This is the term for the extensively folded inner mitochondrial membrane. The folding increases the surface area of the membrane, allowing more proteins to be embedded and thus enhancing the ability of the mitochondrion to produce ATP in cellular respiration.

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

D

Which of the following is part of the endomembrane system?

Golgi apparatus

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

Increased levels of endoplasmic reticulum activity

Tours of a Plant Cell and an Animal Cell -- Comparing Plant and Animal Cells

Lysosome: Found in animal cells Cell wall: Found in plant cells Nucleus: Found in both plant and animal cells Chloroplast: Found in plant cells Rough ER: Found in both plant and animal cells

In which of the following ways do lysosomes work within animal cells?

Lysosomes fuse with food vacuoles, digest food, and release nutrients into the cytosol

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

Microtubules

Where in a cell is ATP made? (animal cell)

Mitochondria

Which of the following is characteristic of prokaryotic cells but NOT eukaryotic cells?

Nucleoid -The nucleoid is the region where DNA is located in prokaryotic cells, which lack membrane-bound organelles. DNA in eukaryotic cells is found in the nucleus, which is enclosed by a phospholipid bilayer membrane.

Where is a bacterial cell's DNA found?

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

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

Nucleus

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

Ribosome, rough endoplasmic reticulum, smooth endoplasmic reticulum

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

Storing compounds produced by the cell

Lysosomal storage diseases are rare in the general population. Why?

Such diseases are usually fatal in early childhood. -Lysosomal storage diseases result from the absence of key digestive enzymes normally present in lysosomes. Without these enzymes, undigested material builds up and interferes with the cell's function. The damage is so extensive that most people with such disorders die at a very early age.

Lysosomes are derived from __________ and function in __________.

The Golgi apparatus and rough endoplasmic reticulum ; Digestion of worn-out organelles

The genes for actin are said to be highly conserved. What does this mean?

The actin gene is similar across many species

Which of the following describes the function of the chloroplast?

The chloroplast converts light energy to chemical energy.

Which of the following developments might have contributed to mitochondria becoming endosymbionts in eukaryotic cells?

The increasing availability of atmospheric oxygen. -As Earth's atmosphere became increasingly oxygen-rich, cells had a survival advantage if they could benefit from an endosymbiont that could use oxygen to release energy. This is the role of mitochondria in eukaryotic cells.

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.

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

They are constructed of a similar type of membrane. -Each of these organelles is a member of the endomembrane system and is constructed of the same type of membrane: a phospholipid bilayer.

In plants, chlorophyll molecules are located within sacs called __________, which in turn are suspended in the __________ of the __________.

Thylakoid ; Stroma ; Chloroplast -The inner membrane of the chloroplast contains a thick fluid called the stroma. Within this, a network of sacs called thylakoids is suspended. These sacs are interconnected and sometimes stacked like poker chips.

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 Submit

Mitochondrion are found in

both plant and animal cells

Animal Cell Structure

irregular round shape (no cell wall) multiple small vacuoles centrioles no chloroplast

Chloroplast

-found only in plant cells and some algae -organelle of photosynthesis -contains thylakoids -produces O2 as a waste product -converts solar energy to chemical energy

One meter consists of _____ millimeters and _____centimeters. How many millimeters are in one centimeter?

1,000 ; 100 ; 10 -1 meter consists of 1,000 millimeters or 100 centimeters. To find the number of millimeters in a centimeter, divide 1,000 by 100. The result is 10 millimeters. In general, the prefixes "centi" (for 100) and "milli" (for 1,000) can help you understand these terms.

In a bacterium, where are proteins synthesized?

Ribosomes

Where are lipids made in the cell?

Smooth endoplasmic reticulum (ER)

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

Desmosomes

___________ 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

Men with primary ciliary dyskinesia (PCD) have recurrent respiratory tract infections and immotile sperm. What is the cause of these symptoms?

A lack of dynein proteins. -Dynein is attached to the outer microtubules in eukaryotic cilia and flagella. Without it, the structures cannot bend. And without bending, cilia lining the trachea (windpipe) cannot sweep out mucus and debris, and sperm cannot travel to the ovum to fertilize it.

A white blood cell is 12-15 µm (microns) in diameter. If you wished to count the white blood cells in a blood sample, which type of microscope would you choose?

A light microscope -Most plant and animal cells can be observed with a light microscope. This level of magnification is sufficient for visualizing a field of cells that are as large as white blood cells.

A transport vesicle within a cell can contain which of the following?

A newly made glycoprotein, as well as the glycoprotein with its attached phosphate groups -Transport vesicles are used for two export functions. First, a protein is exported from the rough endoplasmic reticulum after its manufacture, to the Golgi apparatus, where it will be modified for export from the cell via the cell membrane. Such a modification can include the addition of phosphate groups. (Some proteins will remain within the cell.)

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

C

Plant cell structure

Cell walls, permanent vacuole, chloroplast, cell membrane, cytoplasm, nucleus and mitochondria

__________ is the most prevalent glycoprotein in the extracellular matrix.

Collagen

The most abundant glycoprotein in the extracellular matrix (ECM) is __________. This protein attaches to __________, which are proteins in the plasma membrane that connect the ECM with the inside of the cell.

Collagen ; Integrins -Collagen is the most abundant glycoprotein in the extracellular matrix, as well as accounting for about 40% of the protein in the entire body. Integrins are membrane-spanning proteins that transmit signals between the ECM and the cytoskeleton, where they attach to intercellular microfilaments.

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

Electron microscopy

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

Fimbriae

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

Gap (communicating) junctions

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

Large amounts of endoplasmic reticulum ; Elevated levels of detoxifying enzymes -The smooth endoplasmic reticulum (SER) of liver cells contains enzymes that are involved in alcohol metabolism. With increased alcohol consumption, the amount of SER increases, as does its content of detoxifying enzymes.

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

Lysosome -Lysosomes are membrane-bound sacs containing digestive enzymes that are found only in animal cells. Contractile vacuoles, which keep water and waste products flowing into and out of the cell, perform a similar digestive function in plant cells.

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

Metabolically alive

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

Which of the following is the correct pairing of a cytoskeletal structure and its approximate diameter?

Microtubules: 7 nm

Which of the following is the correct pairing of a microscopic structure and its approximate size?

Mitochondrion: 1 µm

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

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

Nuclear envelope

Tour of an Animal Cell -- Organelle Functions

Nucleus : Stores the genetic information of the cell. Lysosome : Breaks down macromolecules using digestive enzymes. Mitochondrion : Converts chemical fuel into packets of chemical energy that can power the cell. Ribosome : Works to mRNA to synthesize proteins. Smooth ER : Site of lipid synthesis.

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

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

In the most general sense, which of the following is the correct description of cellular respiration?

Oxygen is used, carbon dioxide is released, ATP is created

You, suddenly grown very small because you drank too much TinyMe, are standing between two cells in the trunk of the oak tree behind your apartment. Your feet are stuck in __________. After you free your feet, what is the first barrier that you must cross to enter any of the surrounding cells?

Pectin ; Primary cell wall -The sticky polysaccharide between cells in plants is pectin, used to thicken jams and jellies. The primary cell wall is the most external part of the cell wall, and the strong secondary cell wall in wood lies next to the plasma membrane.

You have identified a new organism. It has ribosomes, chromosomes, a cell wall, and plasmodesmata. This new organism is most likely a __________.

Plant -Plant cells have cell walls that contain plasmodesmata, which are cytoplasmic channels that connect adjacent cells. They also have ribosomes and chromosomes.

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

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

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

RNA

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

Ribosomes.

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

Secrete a lot of material.

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

Several million

Which listed tissue type would you expect to contain a large proportion of anchoring junctions?

Skin -Anchoring junctions are most plentiful in tissue that will be stretched or stressed. Skin undergoes both stretching and stress as part of normal wear-and-tear.

The plasma membrane fits into which of the four general function categories defined in your test?

Support, movement, and communication. -The plasma membrane regulates traffic into and out of the cell. As such, it is an important structure for cell communication with the external environment.

After their synthesis, proteins are modified and sorted by __________ located in the cell's __________. An example of such a modification is __________.

The Golgi apparatus; Cytoplasm; Adding a phosphate group -Proteins are synthesized on ribosomes on the rough endoplasmic reticulum, and then taken by a transport vesicle to the Golgi apparatus in the cell's cytoplasm. After incorporation into the Golgi apparatus, the protein may be modified by adding phosphate groups or altering its carbohydrate portions. It is then removed from the Golgi apparatus by a transport protein or incorporated into the plasma membrane of another organelle.

Pancreatic cells produce large amounts of enzymes for export into the digestive system. By contrast, muscle cells do NOT export digestive enzymes. How do you think that the number of ribosomes compares in the two cell types?

The pancreatic cell has many more ribosomes than the muscle cell. -There are several million ribosomes in cells like those in the pancreas that produce digestive enzymes. The main job of the muscle cell is contraction, not protein synthesis, so it needs far fewer ribosomes.

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

They are constructed of interrelated membranes.

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

Tight junctions

When you hear the terms contractile, digestive, storage, pigment and poisonous, which of the following organelles comes to mind?

Vacuole -Vacuoles perform all of the listed roles, depending on the type of cell they are in. In plants and fungi, vacuoles perform a digestive function. In some protists, contractile vacuoles circulate water throughout the organism. Protein storage vacuoles in plant seeds, pigment vacuoles in flower petals, and vacuoles containing poisonous substances to ward off animals, are other examples.