* All of the Following Statements About Cells Is True

HONORS BIOLOGY 2

A Tour of the Cell Study Guide

* All of the following statements about cells is true.

The common features of prokaryotic and eukaryotic cells are:

DNA, the genetic material contained in one or more chromosomes and located in a nonmembrane bound nucleoid region in prokaryotes and a membrane-bound nucleus in eukaryotes

Plasma membrane, a phospholipid bilayer with proteins that separates the cell from the surrounding environment and functions as a selective barrier for the import and export of materials

Cytoplasm, the rest of the material of the cell within the plasma membrane, excluding the nucleoid region or nucleus, that consists of a fluid portion called the cytosol and the organelles and other particulates suspended in itRibosomes, the organelles on which protein synthesis takes place

* Light microscopes - use light and glass lenses to magnify an image.

* One centimeter = ___10_____ millimeters.

* Resolution is theability of an optical instrument to show two close objects as separate.

*Electron microscopes focus electron beams to create a magnified image of an object

*If a scientist wants to examine living cells lining the respiratory tract to determine how the cells use tiny hairs to move dirt and mucus away from the lungs, he would usea light microscope, because it allows observations of whole, live cells

* The idea that all living things are composed of cells and that all cells come from other cells definescell theory.

* A scientist wants to magnify a pollen grain 8,000 times and examine the ridges and pores on its surface, he would use a scanning electron microscope.

* A scanning electron microscope is used to study cell surfaces, whereas a transmission electron microscope is used tostudy internal cell structures.

* The diameter of most animal and plant cells ranges from10 to 100 micrometers.

* As cell size increases, thevolume increases faster than the surface area.

*Bacteriumcells have the greatest surface-to-volume ratio.

* A cell is exposed to a substance that prevents it from dividing. The cell becomes larger and larger. This situationwill eventually be problematic, since the cell's ability to absorb nutrients through its outer membrane will not keep increasing as quickly as its cytoplasmic needs.

* Your throat is dry, and you want the last cough drop in the box to last a long time in your mouth. You should keep the cough drop whole. This maintains the largest surface-to-volume ratio, and slows the dissolution of the cough drop.

* Archaea are composed ofProkaryoticcells.

*The Nucleoid is exclusively associated with prokaryotic cells

* The nucleoid region of a prokaryotic cellcontains the cell's DNA.

*Prokaryoticcells lack a membrane-enclosed nucleus.

* Both pili and capsulestructures are used by prokaryotes for attaching to surfaces.

* The membranous compartmentalization of a cellallows different metabolic processes to occur simultaneously.

*Eukaryotic cells have the following:

…internal membranes greatly increase a cell's total membrane area.

…internal membranes provide an additional area for many metabolic processes occur.

……. internal membranes form membranous compartments called organelles.

……. internal membranes contain proteins essential for metabolic processes.

* You are told that the cells on a microscope slide are plant, animal, or bacterial. You look at them through amicroscope and see cell walls and membrane-bound organelles. You conclude correctly that the cellsare plant cells.

* Unlike animal cells, plant cells have Chloroplastsand cell walls. Unlike plant cells, animal cells havecentrioles.

*Characteristics ofCellular metabolism include

… Cellular metabolism includes different processes that require different conditions.

….Cellular metabolism can occur within organelles.

… Cellular metabolism can involve the synthesis of steroid hormones.

… Cellular metabolism often occurs on the surfaces of internal membranes.

* Plasma membranes are permeable to nonpolar molecules such as CO2.

*You would you find the following when looking through a SEM at a cell treated with an enzyme that cleaves proteins attheir hydrophilic amino acids.

……..a cell surface that is devoid of any major structures

* The nucleus of a cellcontains DNA.

* Long fibers of DNA and protein are calledchromatin.

* During cell reproduction, chromatin fibers coil up into structures calledchromosomes.

* The function of the nucleolus isto manufacture ribosomal RNA.

* Protein synthesis requires the use of mRNA, whichis translated by the ribosomes into the amino acid sequences of proteins.

* The plasma cell produces thousands of antibodies per second. What type of intracellular structure that would be very prominent within the cell is the endoplasmic reticulum.

*The plasma membrane in the cell is unlikely to contain ribosomes or ribosomal subunits?

*Characteristics of the endomembrane system include

… The endomembrane system is involved in the synthesis, storage, and export of important molecules.

… The endomembrane system includes the rough and smooth endoplasmic reticulum.

… The endomembrane system includes the nuclear envelope.

… The endomembrane system divides the cell into compartments.

* The endomembrane system includes all of the following organelles .

Plasma membrane ,endoplasmic reticulum, Golgi apparatus, and lysosome.

* Smooth endoplasmic reticulumstores calcium ions in muscle cells.

* The two main functions of the rough endoplasmic reticulum are the production ofribosomes and steroid hormones

* Secretory proteins arereleased from the cell through the plasma membrane.

* The cells that produce hair contain a lot of rough endoplasmic reticulum, while the cells that produce the oils that coat the hair contain alot of smooth endoplasmic reticulum.

* The Golgi apparatusstores, modifies, and packages proteins.

*The Golgi apparatus :

…… works closely with the endoplasmic reticulum.

…. serves as a molecular warehouse and finishing factory.

…. modifies chemicals received from the endoplasmic reticulum.

…. sorts molecules according to their destination.

*Lysosomes:

…. help to digest worn-out or damaged organelles.

…. Lysosomes fuse with food vacuoles to expose nutrients to lysosomal enzymes.

… Lysosomes destroy harmful bacteria engulfed by white blood cells.

… Lysosomes recycle materials within the cell.

* When a cell is deprived of oxygen, its lysosomes tend to burst and release their contents into the cell. As a result ofthis, that cell will undergo self-digestion and die.

*Tay-Sachs disease results from the malfunction oflysosomes.

*Tay-Sachs diseasecauses an accumulation of lipids in brain cells.

* Functions of a plant cell central vacuole include:

…… The central vacuole of a plant cell may help increase the size of cells by absorbing water.

…… The central vacuole of a plant cell may store pigments that will help attract pollinating insects.

……. The central vacuole of a plant cell may store waste products.

…… The central vacuole of a plant cell may store poisons.

* Contractile vacuolesprevent cells from bursting as a result of the influx of excess water.

* A manufacturing company dumps its wastes into a nearby pond. One of the wastes is found to paralyze the contractilevacuoles of certain protists. A biologist looking at individual samples of these organisms taken from the pond would findthat they have gained water and burst.

*Peroxisome are involved in the catabolism of fatty acids and the detoxification of alcohol.

* Insulin is a protein that is produced by pancreatic cells and secreted into the bloodstream. The order of the structures through which insulin passes from its production to its exit from the cell is as follows: rough ER, transport vesicles, Golgi apparatus, transport vesicles, cell membrane

* The function of mitochondria is cellular respiration.

* Cyanide inhibits mitochondrial function; as a result, the rate ofATP synthesis decreases.

* The Cristae of a mitochondrion is/are an adaptation that increases the surface area and enhances amitochondrion's ability to produce ATP.

* The function of chloroplasts isphotosynthesis.

* The stroma is thethick fluid enclosed by the inner chloroplast membrane.

* Mitochondria differ from chloroplasts in that mitochondriacontain membrane folds called cristae, whereas chloroplasts contain disk-like vesicles in stacks called grana.

* The endosymbiosis hypothesis proposes thata small cell lived inside a larger cell to the benefit of both cells.

* The endosymbiosis hypothesis is supported by all of the following pieces of evidence;

…mitochondria have circular DNA like prokaryotes, chloroplasts have ribosomes like prokaryotes, mitochondria have a double membrane, chloroplasts split like prokaryotes.

* Microfilaments differ from microtubules in that microfilamentsare mainly composed of actin, whereas microtubules are composed of tubulin.

* The cytoskeleton helps to support cells.

… The cytoskeleton is composed of three types of fibers: microfilaments, microtubules, and intermediate filaments.

… The cytoskeleton plays an important role in amoeboid motion.

… The cytoskeleton includes fibrous and globular proteins.

* Intermediate filamentssurround the nucleus.

* A drug that interferes with microtubule formation is likely to completely disruptthe movements of sperm cells.

* Cilia differ from flagella in thatcilia are typically more numerous and shorter than flagella.

* A basal body issimilar in structure to centrioles.

* Dynein armsare found on microtubules in cilia and flagella and cause movement by grabbing and pulling at adjacent microtubule.

* A woman is having trouble becoming pregnant. Examination of her partner's sperm indicates that dynein arms aremissing from the flagella in his sperm cells. A physician explains that this could interfere with fertility bypreventing the sperm from swimming to the egg cell.

* Decreased fertility in men from developed countries may be related toincreased exposure to hormone-like chemicals in the environment.

* Most animal cells areembedded in an extracellular matrix.

* Most cells from multicellular organisms must be attached to their surroundings via integrins. Failure to maintain thiscontact will usually results inthe death of the cell.

*Integrity of the inner lining of the digestive tractwould be most affected by a mutation that prevented cells from forming tight junctions.

* Skin cells are attached to the extracellular matrix byanchoring junctions.

* It is essential for heart muscle cells to beat in a coordinated fashion. The cell junctions that would best facilitate thisarecommunicating junctions.

*Plant cell walls :

…. consist of cellulose fibers embedded in a matrix of polysaccharides and proteins.

…. The cell wall of one plant cell is separated from the cell wall of another by a layer of sticky polysaccharides.

…. are multilayered structures.

… Wood is primarily composed of plant cell walls.

*Plasmodesmata: penetrate plant cell walls,Plasmodesmata are one type of cell junction in plants,Plasmodesmata carry chemical messages between plant cells,Plasmodesmata carry nutrients between plant cells.

*Peroxisomes are associated with the breakdown of harmful substances or substances that areno longer needed by the cell?

*Characteristics of cells include:?

… All cells are enclosed in a membrane that maintains internal conditions different from the surroundings; can interconvert forms of energy, can interconvert chemical materials, have DNA as their genetic material.

* A child dies following a series of chronic bacterial infections. At the autopsy, the physicians are startled to see that thechild's white blood cells are loaded with vacuoles containing intact bacteria. An explanation for this could be a defect in the lysosomes of the white blood cells prevented the cells from destroying engulfed bacteria.