Chapter 3 Exam 1

Question 1

Which of the following statements about cells is true?
A) All cells have cell walls.
B) All cells have internal structures that move.
C) All cells are attached to other cells.
D) All cells are motile.

Answer 1

Answer: B
Note: Animal cells don’t have cell walls. There are definitely unicellular organisms that are not attached to other cells. Only some cells are motile but not all. Within the cells, there are various transport processes going (e.g. vesicles traveling back and forth from ER to Golgi and to the cell membrane). Proteins and mRNA are constantly being moved within the cell.

Question 2

Light microscopes
A) typically provide more resolution than an electron microscope.
B) work by reflecting electrons off the surface of an object being studied.
C) use light and glass lenses to magnify an image.
D) are generally not used to view bacteria.

Answer 2

Answer: C
Note: Light microscope has resolution limit of 0.2 μm or 200nm electron microscope can see distances down to about 2nm (1 μm=1000nm)

Question 3

One centimeter = millimeters.
A) 0.01
B) 0.10
C) 10
D) 100

Answer 3

Answer: C
Note: cm is NOT an SI unit, you need to convert measurements done in cm to mm if you want to publish your data in a scientific journal in any country. Yes, even US based scientific journals (e.g. Science, Cell, etc) will only accept SI units. Non SI units (such as inches, gallons, oz, etc) are NOT allowed in any scientific publications.

Question 4

Resolution is the
A) ability of an optical instrument to show two close objects as separate.
B) size of an image.
C) ability of an optical instrument to magnify an image.
D) distance between the lenses of a microscope.

Answer 4

Answer: A

Question 5

Which of the following statements about electron microscopes is true?
A) Electron microscopes focus electron beams to create a magnified image of an object.
B) Scanning electron microscopes are used to study the details of internal cell structure.
C) Transmission electron microscopes are mainly used to study cell surfaces.
D) Specimens must be sectioned to be viewed under a scanning electron microscope.

Answer 5

Answer: A
Note: TEM is used to study internal structures and you must make ultra-thin sections to view samples under TEM. SEM is used to study cell surfaces.

Question 6

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. Which of the following instruments would be best, and why?
A) a light microscope, because it allows observations of whole, live cells
B) a transmission electron microscope, because it has high resolution
C) a scanning electron microscope, because it can reveal structures on cell surfaces
D) a scanning electron microscope, because it can be used to observe whole cells without slicing them

Answer 6

Answer: A
Note: You have to fix a specimen and completely dehydrate it before you can see it under an electron microscope.

Question 7

The idea that all living things are composed of cells and that all cells come from other cells defines
A) the laws of inheritance.
B) organelle theory.
C) cell theory.
D) inheritance of acquired characteristics.

Answer 7

Answer: C

Question 8

A scientist wants to magnify a pollen grain 8,000 times and examine the ridges and pores on its surface. Which one of the following instruments would be best?
A) a transmission electron microscope
B) a scanning electron microscope
C) a fluorescence confocal microscope
D) an inverted light microscope

Answer 8

Answer: B
Note: Light microscopes can only magnify things around 2000x, you must use an electron microscope if you want higher magnification.

Question 9

A scanning electron microscope is used to study , whereas a transmission electron microscope is used to study .
A) live cells . . . dead cells
B) cell surfaces . . . internal cell structures
C) dead cells . . . live cells
D) internal cell structures . . . cell surfaces

Answer 9

Answer: B
Note: Scanning electron microscopy works by detecting electrons bouncing off the surface of a specimen, transmission electron microscopy works by shooting electrons through very thin sections of specimen.

Question 10

The diameter of most animal and plant cells ranges from
A) 0.1 to 1.0 micrometers.
B) 1.0 to 10 micrometers.
C) 10 to 100 micrometers.
D) 100 to 1000 micrometers.

Answer 10

Answer: C
Note: Bacteria are typically 1-5 micrometers (μm) in diameter

Question 11

As cell size increases, the
A) volume and surface area decrease.
B) volume increases faster than the surface area.
C) surface area increases faster than the volume.
D) surface area and volume increase at the same rate.

Answer 11

Answer: B
Note: Surface area increases to the square of the diameter, volume increases to the cube (power 3) of the diameter.

Question 12

Which of the following cells has the greatest surface-to-volume ratio?
A) bacterium
B) human red blood cell
C) human muscle cell
D) ostrich egg

Answer 12

Answer: A
Note: The smaller the cell, the larger the surface-to-volume ratio

Question 13

A cell is exposed to a substance that prevents it from dividing. The cell becomes larger and larger. This situation
A) should present no problem to the cell, since it can continue to perform all other necessary functions.
B) should present no problem to the cell, because the surface area of the cell will increase as the volume of the cell increases.
C) will 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.
D) should be beneficial, since the cell will be able to divert the ATP normally used for cell division to other processes.

Answer 13

Answer: C

Question 14

Which of the following statements regarding cells is false?
A) All cells are enclosed in a membrane that maintains internal conditions different from the surroundings.
B) All cells have a cell wall.
C) All cells can interconvert forms of energy.
D) All cells have DNA as their genetic material.

Answer 14

Answer: B
Note: Animal cells, many protists, and some bacterial cells don’t have a cell wall

Question 15

Plasma membranes are permeable to
A) large hydrophilic molecules such as starch.
B) small ions such as Na+.
C) nonpolar molecules such as CO2.
D) hydrophilic molecules such as glucose.

Answer 15

Answer: C
Note: You need to know what can or cannot go through the plasma membrane. Molecules that can go through: small polar or non polar molecules: H2O, ethanol, O2, N2, and CO2, and other dissolved gasses Hydrophobic molecules of any size (lipids, cholesterol, etc) Molecules that can’t go through: large polar molecules (e.g. sugars); any charged particles regardless of size (H+, Na+,K+, Cl-, etc) You’ll see a variation to this question based on the list above !!

Question 16

In the plasma membrane, the phospholipid heads
A) are hydrophilic and face outward towards the aqueous solution on both sides of the membrane
B) are hydrophilic and face inward, shielded from water
C) are hydrophobic and face outward towards the aqueous solution on both sides of the membrane
D) are hydrophobic and face inward, shielded from water

Answer 16

Answer: A
Note: That’s the most energetically favourable state and any amphipathic molecules will naturally fold that way.

Question 17

Archaea are composed of ________ cells.
A) prokaryotic
B) bacterial
C) eukaryotic
D) animal

Answer 17

Answer: A
Note: Bacteria and Archaea are from different domains, Archaea are definitely NOT bacteria even though both are prokaryotic (don’t have a nucleus). Archaea are actually phylogenetically closer to eukarya than bacteria !

Question 18

Which of the following structures is exclusively associated with prokaryotic cells?
A) a membrane-bound nucleus
B) nucleoid
C) chromosome
D) ribosomes

Answer 18

Answer: B
Note: Nucleoid literally means a fake nucleus. Prokayotes DO have DNA that are also organized into a chromosome (usually 1 circular chromosome). The chromosome clustered inside a cell and form the “nucleoid” region. However, it is NOT covered with

Question 19

The nucleoid region of a prokaryotic cell
A) contains the cell’s DNA.
B) separates the RNA from the cytoplasm.
C) is surrounded by a nucleoid membrane.
D) contains the cell’s nucleoli.

Answer 19

Answer: A

Question 20

________ cells lack a membrane-enclosed nucleus.
A) Plant
B) Prokaryotic
C) Eukaryotic
D) Fungal

Answer 20

Answer: B

Question 21

A bacterial cell’s DNA is found in its
A) ribosomes.
B) nucleus.
C) nucleoid region.
D) capsule.

Answer 21

Answer: C
Note: Nucleoid simply means “fake nucleus”. Bacteria don’t have a true nucleus (nucleus surrounded by a nuclear envelope) but doesn’t mean bacteria don’t have DNA.

Question 22

Which of the following cell structures is associated with the breakdown of harmful substances or substances that are no longer needed by the cell?
A) chloroplasts
B) mitochondria
C) peroxisomes
D) centrioles

Answer 22

Answer: C
Note: Both the lysosomes and peroxisomes may do that.

Question 23

The membranous compartmentalization of a cell
A) divides the cell into two equal-sized halves.
B) allows different chemical conditions to be maintained in different parts of the cell.
C) requires the presence of a cell wall.
D) is common to both prokaryotes and eukaryotes.

Answer 23

Answer: B

Question 24

Which of the following statements about internal membranes in eukaryotic cells is false?
A) In eukaryotic cells, internal membranes greatly increase a cell’s total membrane area.
B) In eukaryotic cells, internal membranes provide an additional area for many metabolic processes to occur.
C) In eukaryotic cells, internal membranes form membranous compartments called organelles.
D) In eukaryotic cells, internal membranes standardize the internal environment of all cellular organelles.

Answer 24

Answer: D
Note: Eukaryotic membranes allow differentiation and compartmentalization of the content inside the cell.

Question 25

You are told that the cells on a microscope slide are plant, animal, or bacterial. You look at them through a microscope and see cell walls and membrane-bound organelles. You conclude correctly that the cells A) are plant cells. B) are animal cells. C) are bacterial cells. D) could be either plant or bacterial cells.

Answer 25

Answer: A Note: Membrane-bound organelles means it has to be a eukaryote. Plants have cell walls and animal cells don’t.

Question 26

Unlike animal cells, plant cells have ________ and ________. Unlike plant cells, animal cells have ________. A) chloroplasts . . . cell walls . . . centrioles B) centrioles . . . chloroplasts . . . cell walls C) chloroplasts . . . cell walls . . . a nucleus D) centrioles . . . cell walls . . . large central vacuoles

Answer 26

Answer: A Note: Apart from chloroplasts, a large central vacuole is unique to plants cells as well. You may see a variation to this question!

Question 27

Which of the following statements about cellular metabolism is false? A) Cellular metabolism includes different processes that require different conditions. B) Cellular metabolism can occur within organelles. C) Cellular metabolism occurs in animal but not plant cells. D) Cellular metabolism often occurs on the surfaces of internal membranes.

Answer 27

Answer: C Note: Plant cells clearly carry out metabolism to stay alive.

Question 28

The nucleus of a cell A) is surrounded by a single layer of membrane. B) is contained within the nucleolus. C) contains DNA. D) is the primary location of protein synthesis.

Answer 28

Answer: C

Question 29

The complex of proteins and DNA in a nondividing cell is called A) chromatin. B) a nucleolus. C) a ribosome. D) a lysosome.

Answer 29

Answer: A Note: Chromatins are uncondensed chromosomes. You will typically only see chromosomes when the cells are dividing.

Question 30

During cell reproduction, chromatin fibers coil up into structures called A) ribosomes. B) lysosomes. C) chromosomes. D) nucleoli.

Answer 30

Answer: C

Question 31

The function of the nucleolus is A) to manufacture polypeptides. B) to manufacture ribosomal RNA. C) intracellular digestion. D) to store chromatin.

Answer 31

Answer: B Note: Nucleolus is an area inside the eukaryotic nucleus that is active in RNA transcription or DNA replication. It could be making either rRNA or mRNA. It is not technically a real structure. There could be multiple nucleoli inside the nucleus. When a particular region of the nucleus is active in RNA transcription, it picks up a little more stain and appears darker inside the nucleus. Different regions of a nucleus may undergo transcription at different times. There may not be any visible nucleoli when the cell is resting and not transcriptionally active.

Question 32

Protein synthesis requires the use of mRNA, which A) is made in the nucleolus. B) must be made by the ribosomes. C) is translated by the ribosomes into the amino acid sequences of proteins. D) carries the message to the nucleus to synthesize new DNA during cell division.

Answer 32

Answer: C

Question 33

Which location in the cell is unlikely to contain ribosomes or ribosomal subunits? A) nuclear envelope B) plasma membrane C) endoplasmic reticulum D) cytoplasm

Answer 33

Answer: B Note: Ribosomes are either found free standing in the cytoplasm or attached to the rough ER. Since the nuclear envelope is physically attached to the ER, there are some ribosomes attached to it as well. rRNA (part of ribosomes) are constantly being exported out of the nucleus. Therefore, you’ll find some rRNA in the nuclear pore complex located on the nuclear envelope as well.

Question 34

Which of the following statements regarding the endomembrane system is false? A) The endomembrane system is involved in the synthesis, storage, and export of important molecules. B) The endomembrane system includes the rough and smooth endoplasmic reticulum. C) The endomembrane system includes the nuclear envelope. D) The endomembrane system is a system of interrelated membranes that are all physically connected.

Answer 34

Answer: D Note: The Golgi and the ER are NOT physically connected. The ER is physically connected to the nuclear envelope.

Question 35

The endomembrane system includes all of the following organelles except the A) plasma membrane. B) endoplasmic reticulum. C) peroxisome. D) Golgi apparatus.

Answer 35

Answer: C Note: The endomembrane system consists of: ER, Golgi, endosomes, lysosomes, and plasma membrane. You are expected to know which organelles are part of the endomembrane system and which are not. You may see a variation of this question in the exam.

Question 36

An immune system cell called the plasma cell produces thousands of antibodies per second for release into the body. What type of intracellular structure would you expect to be very prominent within the cell? A) nucleus B) endoplasmic reticulum C) peroxisome D) microtubules

Answer 36

Answer: B Note: Any cells that are active in secreting protein-based substances (in this case antibodies) should have an extensive network of rough ER and Golgi.

Question 37

Smooth endoplasmic reticulum A) stores calcium ions in muscle cells. B) is the major site of carbohydrate synthesis in eukaryotic cells. C) produces proteins for cell membranes. D) helps assemble ribosomes for protein synthesis.

Answer 37

Answer: A Note: Smooth ER also synthesizes lipids and cholesterol. You may see a variation of this question in the exam!

Question 38

The two main functions of the rough endoplasmic reticulum are the production of A) mitochondria and proteins secreted by the cell. B) hydrogen peroxide and steroid hormones secreted by the cell. C) ribosomes and steroid hormones. D) membrane and proteins secreted by the cell.

Answer 38

Answer: D

Question 39

Secretory proteins are A) produced by ribosomes on the smooth endoplasmic reticulum. B) chemically modified in the nucleus. C) produced by the cell for internal use. D) released from the cell through the plasma

Answer 39

D

Question 40

The cells that produce hair contain a lot of ________, while the cells that produce the oils that coat the hair contain a lot of ________. A) smooth endoplasmic reticulum . . . lysosomes B) rough endoplasmic reticulum . . . smooth endoplasmic reticulum C) smooth endoplasmic reticulum . . . rough endoplasmic reticulum D) microbodies . . . lysosomes

Answer 40

Answer: B Note: Hair consists mainly of keratin (a protein!) and is made by the rough ER, lipids are made by smooth ER.

Question 41

The Golgi apparatus A) is composed of stacks of membranous vesicles that are continuous with one another. B) stores, modifies, and packages proteins. C) strings together amino acids to produce proteins. D) is the site of carbohydrate breakdown.

Answer 41

Answer: B

Question 42

Which of the following statements regarding the Golgi apparatus is false? A) The Golgi apparatus works closely with the endoplasmic reticulum. B) The Golgi apparatus serves as a molecular warehouse and finishing factory. C) The Golgi apparatus decreases in size when a cell increases its protein production. D) The Golgi apparatus modifies chemicals received from the endoplasmic reticulum.

Answer 42

Answer: C Note: Proteins need to go through Golgi before secretion as well. You’ll expect a cell active in protein secretion will have expanded Golgi.

Question 43

Which of the following statements about lysosomes is false? A) Lysosomes help to digest worn-out or damaged organelles. B) Lysosomes synthesize proteins from the recycled amino acids. C) Lysosomes fuse with food vacuoles to expose nutrients to lysosomal enzymes. D) Lysosomes destroy harmful bacteria engulfed by white blood cells.

Answer 43

Answer: B Note: Lysosomes hydrolyses proteins to form amino acids for recycling to make new proteins.

Question 44

When a cell is deprived of oxygen, its lysosomes tend to burst and release their contents into the cell. As a result of this, that cell will A) recycle damaged organelles. B) undergo cell division. C) produce replacement lysosomes. D) undergo self-digestion and die.

Answer 44

Answer: D

Question 45

Tay-Sachs disease results from the malfunction of A) mitochondria. B) lysosomes. C) endoplasmic reticulum. D) nucleoli.

Answer 45

Answer: B

Question 46

Tay-Sachs disease A) causes an accumulation of lipids in brain cells. B) involves damage to liver cells. C) is due to the absence of an enzyme that digests polysaccharides. D) prevents the breakdown of glycogen.

Answer 46

Answer: A Note: Tay-Sachs disease is a rare genetic disorder passed from parents to child. It's caused by the absence of an lysosomal enzyme that helps break down fatty substances. These fatty substances, called gangliosides, build up to toxic levels in the brain and spinal cord and affect the function of the nerve cells.

Question 47

Which of the following statements about the functions of a plant cell central vacuole is false? A) The central vacuole of a plant cell may help increase the size of cells by absorbing water. B) The central vacuole of a plant cell may store waste products. C) The central vacuole of a plant cell may digest chemicals for recycling. D) The central vacuole of a plant cell may store poisons.

Answer 47

Answer: C Note: The central vacuoles in plants don’t have digestive functions. They only serve as storage organelles.

Question 48

Contractile vacuoles A) are generally found in protists that inhabit salt water. B) help in the excretion of excess salt. C) prevent cells from bursting as a result of the influx of excess water. D) allow organisms to avoid dehydration by absorbing water from the environment.

Answer 48

Answer: C Note: Contractile vacuoles refer to vacuoles developed by protists living in freshwater that help to remove excess water from the cell. It requires energy to operate and the cells would burst due to influx of water if contractile vacuoles do not work properly.

Question 49

Which organelle is involved in the catabolism of fatty acids and the detoxification of alcohol? A) peroxisome B) Golgi apparatus C) smooth ER D) ribosomes

Answer 49

Answer: A Note: Peroxisome are involved in break down of fatty acids (NOT synthesis) and detoxifying alcohol into less harmful substances.

Question 50

Insulin is a protein that is produced by pancreatic cells and secreted into the bloodstream. Which of the following options correctly lists the order of the structures through which insulin passes from its production to its exit from the cell? A) rough ER, transport vesicles, Golgi apparatus, transport vesicles, cell membrane B) rough ER, lysosomes, transport vesicles, cell membrane C) rough ER, Golgi apparatus, smooth ER, cell membrane D) rough ER, transport vesicles, Golgi apparatus, vacuole, cell membrane

Answer 50

Answer: A Note: Protein synthesis for a secreted protein occurs on the ribosomes attached to the ER, the protein is translocated into the rough ER as they are being synthesized. Folding and processing of proteins occurs inside the rough ER. Then, the protein is packaged into transport vesicles and delivered to the Golgi where further modifications of the protein may take place. The protein is then again packaged into transport vesicles and transported to the cell membrane to be secreted out of the cell. Proteins that are not folded properly and other materials the cell wants to digest/recycle may be sorted to the lysosomes for recycling!. The rough ER, Golgi, transport vesicles and the lysosomes are collectively known as the “endomembrane system”.

Question 51

The function of mitochondria is A) cellular respiration. B) lipid synthesis. C) photosynthesis. D) intracellular digestion.

Answer 51

Answer: A Note: We will discuss cellular respiration in detail in chapter 6.

Question 52

The ________ of a mitochondrion is/are an adaptation that increases the surface area and enhances a mitochondrion's ability to produce ATP. A) stroma B) intermembrane space C) cristae D) matrix

Answer 52

Answer: C Note: Internal foldings of mitochondria are called cristae. We will discuss cellular respiration in detail in chapter 6.

Question 53

The function of chloroplasts is A) cellular respiration. B) lipid synthesis. C) photosynthesis. D) intracellular digestion.

Answer 53

Answer: C Note: We will discuss photosynthesis in detail in chapter 5.

Question 54

The endosymbiosis hypothesis proposes that A) two cells were juxtaposed and one benefited from the other. B) a small cell lived inside a larger cell to the benefit of both cells. C) a large cell engulfed and digested a smaller cell, exposing its enzymes for use by the larger cell. D) two cells merged into one cell, improving the enzyme function of the new cell.

Answer 54

Answer: B

Question 55

The endosymbiosis hypothesis is supported by all of the following pieces of evidence, except the fact that A) mitochondria have circular DNA like prokaryotes. B) mitochondria use ATP like prokaryotes. C) chloroplasts have ribosomes like prokaryotes. D) chloroplasts reproduce through a splitting process like certain prokaryotes.

Answer 55

Answer: B Note: Mitochondria produce ATP like prokaryotes, not use ATP like prokaryotes. The endosymbiotic theory suggests that chloroplasts and mitochondria were free living bacteria in the past but have come to live inside eukaryotic cells. This is still evident by the fact that they still behave like bacteria living inside the host. The evidence include: they both still have their own bacterial-like circular genome, have their own bacterial like ribosomes (70S) and make their own proteins. Their cell membranes also contain proteins that are unique to prokaryotes. They also divide themselves independently of the host’s reproduction!

Question 56

Cilia differ from flagella in that A) cilia contain nine microtubule doublets surrounding a central pair of microtubules, while flagella contain only nine microtubule doublets. B) the protein filaments of cilia are "naked," while those of flagella are wrapped in an extension of the cell membrane. C) cilia are typically more numerous and shorter than flagella. D) cilia are anchored only in the proteins of the cell membrane, while flagella are anchored in a special structure called the basal body.

Answer 56

Answer: C They only differ in length. Cilia are usually shorter and flagella are longer. They actually use the same mechanism to generate motility

Question 57

Most animal cells are A) surrounded by a cell wall. B) attached to each other via plasmodesmata. C) embedded in an extracellular matrix. D) embedded in a lipid matrix.

Answer 57

Answer: C Note: that’s true. Most animal cells are embedded in the extracellular matrix. Animal cells don’t have cell wall or plasmodesmata. The extracellular matrix is made up of complex carbohydrates like hyaluronic acid, glucosamine, cartilage and other proteins, generally not lipids.

Question 58

Which of the following statements regarding plasmodesmata is false? A) Plasmodesmata penetrate plant cell walls. B) Plasmodesmata carry chemical messages between plant cells. C) Plasmodesmata carry nutrients between plant cells. D) Plasmodesmata are found in plants as well as some single-celled organisms.

Answer 58

Answer: D Note: plasmodesmata (holes on the cell wall) are only found in plants

Question 59

Bacterial ribosomes are _______ consisting of a _____ large submit and a _______ subunit; eukaryotic ribosomes are ______ consisting of a _______ large subunit and a _______ subunit A) 70, 50, 30; 80, 60, 40 B) 80, 50 , 30; 100, 60, 40 C) 80, 50, 30; 70, 60, 40 D) 30, 50, 80; 40, 60, 80

Answer 59

answer: A S is an arbitrary number referring to a particular speed you can spin the particle down in a ultracentrifuge. The bigger the molecule, the larger the S value, but size and S values are not directly proportional.