Chapter 4

Which scientist first viewed living cells?

Anton van Leeuwenhoek

theory states that the cell is the smallest unit of life. In other words, a single cell has the potential to carry out all the activities of life.

cell

If a toxin, such as a bacterial toxin, destroys ribosomes, what cellular activity will be affected first?

protein synthesis

Microfilaments.....intermidiate filaments

function in cell movement... stabalize cell shape

The ratio of the size of the image seen with the microscope to the actual size of the object is called:

magnification

Lysosome

-Contain hydrolytic enzymes -Digest bacteria and debris

Cilia vs Flagella

Cilia are smaller than flagella and are used to move substances across the cell surface. Flagella are long and help the cell move through watery environments

Which cell covering is a coat composed of polysaccharides that protects the cell?

Glycocalyx

The Golgi complex is responsible for which processes? Select all that apply.

Making lysosomes,Modifying proteins,Processing and sorting proteins

Glycocalyx

Matrix that aids cells in recognition, contact, and adhesion to other cells.outside of the cell wall, can help with mechanical strength (multicellular tissues)

The ratio of the surface area of a cell's plasma membrane to its volume is the reason for which of the following?

Most cells are microscopic.

Which of the following are characteristics of flagella?

Movable structure,Project from the cell surface,Typically long

Which of the following is defined as the semifluid interior of the nucleus?

Nucleoplasm

What cellular structure contains the DNA?

Nucleus

Carry out metabolic reactions (such as harvesting the chemical energy of fuel molecules to make ATP)

Prokaryotic Proteins in the cytosol and plasma membrane, Eukaryotic Proteins in the cytosol and mitochondria

Prokaryotic vs Eukaryotic Cells

Prokaryotic cells do not have a nucleus or membrane bound organelles, while Eukaryotic cells have specialized membrane bound organelles and a membrane enclosed nucleus.

Store genetic information in the form of DNA

Prokaryotic chromosome, located in the nucleoid, Eukaryotic chromosomes

Build support structures to protect against environment

Prokaryotic, Cell wall, eukaryotic cell wall and cytoskeleton, and extracellular matrix

Which of the following are the only molecules built by ribosomes and rough endoplasmic reticulum (RER)?

Proteins

What do eukaryotic cells contain that prokaryotic cells do not? Select all that apply.

Significant internal membrane organization,A membrane-enclosed nucleus

cell fractionation

Technique used to separate parts of cells. Cells are broken by centrifugation and the organelles are separated by their density. The most dense organelles will sink while the less dense organelles will be suspended.

Resolution

The ability to see two objects separately/ the ability to distinguish two objects from each other

Significance of Cell Size & Surface Area

The cell's surface area to volume ratio decreases as the cell gets larger. Because cells are very small, their surface area to volume ratio is very large, enabling the cell to exchange nutrients and waste in an out of the cell at a very quick rate.

In the classic experiments by Bracht and Hammerling, the nucleus of Acetabularia was removed, the cap was cut off, a nucleus of a different species was inserted, and the cap was allowed to regenerate. The new cap was then removed. After the second regeneration, the cap was observed, and the following conclusion was made:

The shape of the cap was controlled by the nucleus, thus, the nucleus was the control center of the cell.

Briefly explain the relationship between the surface area and volume of a cell and overall cell size. List two ways in which organisms have successfully "solved" this problem.

The surface area of a cell must be large enough to support the metabolism of the cell volume. To solve this problem some cells have long flat extensions and others have fingerlike projections to increase surface area.

Intermediate Filaments

-10 nm in diameter -Tough, flexible Provide strength and stabilization for cell

Vacuoles

-Large membrane enclosed sacs -Have role in plant growth and development -Break down waste in plant cells -Store water and nutrients

Ribosome

-Large subunit and small subunit -Synthesize proteins

Functions of Cell Membranes

-Membrane enclosed organelles for the cell to carry out several functions simultaneously -Chemical reactions in cells are carried out on enzymes bound to membranes -Membranes allow cells to store energy

Peroxisomes

-Metabolize organic molecules - specific type of digestion transfer a hydrogen group to an oxygen group (during enzymatic reaction)

Rough Endoplasmic Reticulum

-Ribosomes are attached -Synthesize proteins

Golgi complexes of prokaryotic cells produce extracellullar polysaccharides that are used to make cell walls.

False (answer plants)

Which of the following are characteristics of microtubules

Function in intracellular movement,Function in cellular movement,Thickest filaments of cytoskeleton,Help move chromosomes

Proteins made on ribosomes may be further modified within the:

Golgi complex

The __________ can be considered a sorting, processing and packaging center.

Golgi complex

Which of the following characteristics is specific to prokaryotic cells?

Plasmids

Mitochondria

Powerhouse of the cell

The smooth endoplasmic reticulum:

Synthesizes lipids for use in the cell membrane and other parts of the cell.

Path of Protein Through the Endomembrane System

The protein is first made and packaged by the rough ER. The protein is enclosed in a transport vesicle and travels to the cis face of the Golgi. The transport vesicle fuses with the cis face of the Golgi and the protein enters the Golgi. The Golgi modifies and packages the protein as it travels through the medial region. The protein exits the trans face in a new vesicle.

Scanning Electron Microscope (SEM)

Used to see details on the surface of cells

Transmission Electron Microscope (TEM)

Used to see the details of cellular components and internal cellular structures

Basic similarities between living cells today suggest they evolved from

a common ancestor

The cis face of the Golgi complex is most directly involved in which of the following?

accepting vesicles from the ER

Evidence that all living cells have a common origin is provided by

basic similarities in cell structure and chemistry.

One strategy that allows larger cells to have an effective surface area to volume ratio is

being short and fat.

ribosomes

can be found free in the cytosol, or attached to certain membranes

Which of the following are specialized structures of plant cells? Select all that apply.

central vacuoles, chloroplasts, and cell wall

A basal body is most closely related to a:

centriole.

... is a combination of DNA

chromatin

DNA is associated with proteins, forming a complex called:

chromatin

when DNA is duplicated

copy intact to one of the two daughter cells

Fluorescence microscope

detect the location of specific molecules in cells, transmit light emitted by Flo. moleculecules, absorb light energy, then release

One function of peroxisomes involves the process of:

detoxification

Which technique allows scientists to see the smallest details of cells?

electron microscope

Enzymes called proteases in the ER lumen catalyze folding of proteins into proper conformations.

false (answer is molecular chaperones)

. You want to determine the location of a specific protein in a cell using a colored stain. Which of the following is the best technique for this purpose?

fluorescence microscopy

ECM

gel structure, carbohydrate, fibernectins help to organize the ECM and attach cells to some of the stronger components like collagen, integrins- between ECM and intermediate filaments, can anchor cells

The scanning electron microscope differs from the transmission electron microscope in that the scanning electron microscope:

gives a three dimensional image of the object being studied.

Which of the following is a cell covering or part of a cell covering?

glycocalyx, extracellular matrix,cell wall, integrins

nuclear pores

holes in the nuclear envelope that allow materials to pass in and out of the nucleus

Which of the following pairs is correctly matched?

integrins−receptors

Where does aerobic respiration take place inside mitochondria?

matrix

dymein

minus end

nucleolis

not enclosed by a membrane, contains nuclear organizer(overlapping regions of DNA from overlapping chromosomes)

A single cell in a smoker's lung has become cancerous. It doubles its DNA and divides much faster than a normal lung cell. The most likely change that would have caused this condition took place in the:

nucleus

Electron microscopes have a much higher resolution than either the human eye or any light microscope because:

of the very short (nanometer) wavelengths of electrons.

Mitochondria are an example of _____.

organelles found within eukaryotic cells

aerobic respiration

oxygen required, includes most of the reactants that convert the chemical energy present in food to energy

Cholorplast are classifies as

plastids

kiesin

plus end

... found in the nucleus

protein

Dark field microscope

rays of light are emitted from the side and only light SCATTERED b y the specimen enters the lens. Dark background

mitotic spindle

serves as the framework for the orderly distribution of chromosomes during cell division

All of the following functions are performed by plant vacuoles EXCEPT

storage of nucleic acids.

vacuoles, lysosomes, peroxisomes

store, digest, detoxify

Phase contrast microscopy

takes advantage of the variation of density within the cell, the density variations affect how different regions of the cytoplasm retract light

Cells that secrete large amounts of glycoprotein have many Golgi stacks.

true

Each protein that goes through the pore has a

(NLS nuclear localization signal) apart of its amino acid sequence

What structure allows only certain molecules to pass into or out of the cell?

Cell membrane

Microfilaments

-7 nm in diameter -Solid and flexible -Made of two intertwined chains of beadlike actin molecules -Form cell cortex inside plasma membrane -Generate movement (actin and myosin)

Cell Theory

-Cells are the basic living units of organization and function -All cells come from other cells -All cells have a common origin

Nucleus

-Contains nucleolus where rRNA is made -Enclosed by nuclear envelope made of an inner and outer membrane -Nuclear pores for transport in and out of nucleus -Control center of cell

Smooth Endoplasmic Reticulum

-Does not have ribosomes attached --Synthesize lipids -Break down toxins

Matching

-Epithelial cells are rectangular. -White blood cells can change shape. -Nerve cells have long, thin extensions. -Sperm cells have flagella.

Golgi Complex

-Has flattened membranous sacs called cisternae -Cis face for entry -Medial region between cis and trans face -Trans face for exit -Processes, sorts, and modifies proteins

Microtubules

-Hollow, rigid rods -MAPs regulate assembly -Aid in movement -Kinesin moves organelles towards plus end of microtubule -Dynein moves organelles towards minus end

Mitochondria

-Inner and outer membranes -Cristae are the inner folds -Matrix in space between cristae -Produce ATP through aerobic respiration

Chloroplasts

-Inner and outer membranes -Disks called thylakoids, Granum are stacks of thylakoids -Stroma is fluid surrounding grana -Produce glucose through photosynthesis

On average, eukaryotic cells are approximately _____ prokaryotic cells.

10 times larger than

Which of the following best describes the nuclear envelope?

A double lipid bilayer

Centrosomes

Aid in cell division

Magnification

Ratio of the size of the object seen with the microscope to the actual size of the object (the ability to make a small object seem larger)

Every cell has a plasma membrane that performs which of the following functions? Select all that apply.

Separating the cell from its external environment,Selectively exchanging materials with its external environment

Importins..... process

binds with NLS form cargo complex captured by nuclear pore machinery , transported through the pore, to the nucleus

A glycoprotein destined for secretion from the cell would move through the Golgi complex in this

cis face to medial region to trans face

During development apoptosis is initiated by the

mitochondria

Which organelles produce food? S

plastids and chloroplasts

A glycoprotein that will become a membrane component will take which of the following paths

rough er, vesicle, cis Golgi, trans gold, vesicle, plasma membrane

Differential centrifugation is a process that:

separates components of the cell that have different densities.

Confocal microscopy

sharp images, uses a laser to excite flouphores in just a slice through the cell (red)

In animal cells the main microtubule organizing center (or centrosome) is important in cell division.

true

Light microscopy

use of any kind of microscope that uses visible light to observe specimens

large amounts of energy consumed in the nucleus

used to synthesize mRNA

Bright-field microscopy

white background, image formed through transmission of light through cell. (DETAILS OF CELL STRUCTURE ARE NOT VISIBLE)