Chapter 4 Flashcards

Cell Structure

1
Q

cell wall

A

rigid cell covering comprised of various molecules that protects the cell, provides structural support, and gives shape to the cell

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2
Q

central vacuole

A

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

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3
Q

centrosome

A

region in animal cells made of two centrioles
that serves as an organizing center for microtubules

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4
Q

chlorophyll

A

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

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5
Q

chloroplast

A

plant cell organelle that carries out
photosynthesis

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6
Q

chromatin

A

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

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7
Q

chromosome

A

structure within the nucleus that comprises chromatin that contains DNA, the hereditary material

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8
Q

cilium

A

(plural = cilia) short, hair-like structure that extends from the plasma membrane in large numbers and functions to move an entire cell or move substances along the cell’s outer surface

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9
Q

cytoplasm

A

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

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10
Q

cytoskeleton

A

protein fiber network that collectively
maintains the cell’s shape, secures some organelles in
specific positions, allows cytoplasm and vesicles to move
within the cell, and enables unicellular organisms to
move independently

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11
Q

cytosol

A

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

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12
Q

desmosome

A

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

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13
Q

electron microscope

A

an instrument that magnifies an
object using an electron beam that passes and bends
through a lens system to visualize a specimen

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14
Q

endomembrane system

A

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

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15
Q

endoplasmic reticulum (ER)

A

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

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16
Q

eukaryotic cell

A

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

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17
Q

extracellular matrix

A

material secreted from animal or
fungal cells that provides mechanical protection and
anchoring for the cells in the tissue

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18
Q

flagellum

A

(plural = flagella) long, hair-like structure that
extends from the plasma membrane and moves the cell

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19
Q

gap junction

A

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

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20
Q

Golgi apparatus

A

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

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21
Q

intermediate filament

A

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

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22
Q

light microscope

A

an instrument that magnifies an object
using a beam of visible light that passes and bends
through a lens system to visualize a specimen

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23
Q

lysosome

A

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

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24
Q

microfilament

A

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

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25
Q

microscope

A

an instrument that magnifies an object

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26
Q

microtubule

A

the cytoskeleton system’s widest element; 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

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27
Q

mitochondria

A

(singular = mitochondrion) cellular
organelles responsible for carrying out cellular
respiration, resulting in producing ATP, the cell’s main
energy-carrying molecule

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28
Q

nuclear envelope

A

double-membrane structure that
constitutes the nucleus’ outermost portion

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29
Q

nucleoid

A

central part of a prokaryotic cell’s central part
where the chromosome is located

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30
Q

nucleolus

A

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

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31
Q

nucleoplasm

A

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

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32
Q

nucleus

A

cell organelle that houses the cell’s DNA and
directs ribosome and protein synthesis

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33
Q

organelle

A

compartment or sac within a cell

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34
Q

peroxisome

A

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

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35
Q

plasma membrane

A

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

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36
Q

plasmodesma

A

(plural = plasmodesmata) channel that passes between adjacent plant cells’ cell walls, connects
their cytoplasm, and allows transporting of materials
from cell to cell

37
Q

prokaryote

A

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

38
Q

ribosome

A

cellular structure that carries out protein
synthesis

39
Q

rough endoplasmic reticulum (RER)

A

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

40
Q

smooth endoplasmic reticulum (SER)

A

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

41
Q

tight junction

A

protein adherence that creates a firm seal
between two adjacent animal cells

42
Q

unified cell theory

A

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

43
Q

vacuole

A

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

44
Q

vesicle

A

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

45
Q

Prokaryotic cells are much smaller than eukaryotic cells. What advantages might small cell size
confer on a cell? What advantages might large cell size
have?

A

A small cell size enables for more efficient transport of chemicals via the plasma membrane while using less energy. While a large cell size allows for compartment division. Organelles perform various tasks in the cell, allowing it to generate complex compounds.

46
Q

If the nucleolus were not able to carry out its function, what other cellular organelles would be
affected?

A

Free ribosomes and rough endoplasmic reticulum (which contains ribosomes) would not be able to form.

47
Q

If a peripheral membrane protein were synthesized in the lumen (inside) of the ER, would it end
up on the inside or outside of the plasma membrane?

A

It would end up on the outside. After the vesicle passes through the Golgi apparatus and fuses with the plasma membrane, it turns inside out.

48
Q

When viewing a specimen through a light microscope,
scientists use ________ to distinguish the individual
components of cells.

A

special stains

49
Q

The ________ is the basic unit of life.

A

cell

50
Q

Prokaryotes depend on ________ to obtain some
materials and to get rid of wastes.

A

diffusion

51
Q

Bacteria that lack fimbriae are less likely to ________.

A

adhere to cell surfaces

52
Q

Which of the following organisms is a prokaryote?

A

e. coli (bacteria)

also, algae and bacteria are prokaryote

53
Q

Which of the following is surrounded by two
phospholipid bilayers?

A

the nucleoplasm

54
Q

Peroxisomes got their name because hydrogen peroxide
is:

A

produced during their oxidation reactions

55
Q

In plant cells, the function of the lysosomes is carried out
by __________.

A

vacuoles

56
Q

Which of the following is both in eukaryotic and
prokaryotic cells?

A

ribosomes

57
Q

Tay-Sachs disease is a genetic disorder that results in the
destruction of neurons due to a buildup of sphingolipids
in the cells. Which organelle is malfunctioning in Tay-
Sachs?

A

lysosome

Tay-Sachs disease is categorized as alysosomal storage disease.

58
Q

Which of the following is not a component of the
endomembrane system?
a. mitochondrion
b. Golgi apparatus
c. endoplasmic reticulum
d. lysosome

A

mitochondrion

59
Q

The process by which a cell engulfs a foreign particle is
known as:

A

phagocytosis

60
Q

Which of the following is most likely to have the greatest
concentration of smooth endoplasmic reticulum?

A

a cell that makes steroid hormones

61
Q

Which of the following sequences correctly lists in order
the steps involved in the incorporation of a
proteinaceous molecule within a cell?

A

synthesis of the protein on the ribosome; modification in the endoplasmic reticulum; tagging
in the Golgi; distribution via the vesicle

62
Q

Congenital disorders of glycosylation are a growing class
of rare diseases. Which organelle would be most
commonly involved in the glycoprotein disorder portion
of the group?

A

Golgi apparatus

63
Q

Which of the following have the ability to disassemble
and reform quickly?

A

microfilaments and microtubules

64
Q

Which of the following do not play a role in intracellular movement?

A

only intermediate filaments

65
Q

In humans, _____ are used to move a cell within its
environment while _____ are used to move the
environment relative to the cell.

A

flagella; cilia

66
Q

Which of the following are only in plant cells?

A

Plasmodesmata are only present in plant cells.

67
Q

The key components of desmosomes are cadherins and
__________.

A

The key components of desmosomes are cadherins and intermediate filaments.

68
Q

Diseased animal cells may produce molecules that
activate death cascades to kill the cells in a controlled
manner. Why would neighboring healthy cells also die?

A

The death molecule passes through gap junctions.

69
Q

In your everyday life, you have probably noticed that
certain instruments are ideal for certain situations. For
example, you would use a spoon rather than a fork to eat
soup because a spoon is shaped for scooping, while soup
would slip between the tines of a fork. The use of ideal
instruments also applies in science. In what situation(s)
would the use of a light microscope be ideal, and why?

A

A light microscope would be ideal when viewing a small living organism, especially when the cell has been stained to reveal details.

70
Q

In what situation(s) would the use of a scanning electron
microscope be ideal, and why?

A

A scanning electron microscope would be ideal when you want to view the minute details of a cell’s surface, because its beam of electrons moves back and forth over the surface to convey the image.

71
Q

In what situation(s) would a transmission electron microscope be ideal, and why?

A

A transmission electron microscope would be ideal for viewing the cell’s internal structures, because many of the internal structures have membranes that are not visible by the light microscope.

72
Q

What are the advantages and disadvantages of each of these types of microscopes?

A

The advantages of light microscopes are that they are easily obtained, and the light beam does not kill the cells. However, typical light microscopes are somewhat limited in the amount of detail they can reveal. Electron microscopes are ideal because you can view intricate details, but they are bulky and costly, and preparation for the microscopic examination kills the specimen.

73
Q

Unified cell theory

A

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

74
Q

Explain how the formation of an adult human follows
the cell theory.

A

An adult human is created from the single-celled zygote that divides by mitosis to form a ball of cells called the embryo. The cells group and differentiate into specialized cells to form the different tissues and organs.

75
Q

Antibiotics are medicines that are used to fight bacterial
infections. These medicines kill prokaryotic cells
without harming human cells. What part or parts of the
bacterial cell do you think antibiotics target? Why?

A

Antibiotics target the bacterial cell wall or membrane, protein machinery, or nucleic acid machinery to kill the bacteria or stop its growth and replication.

76
Q

Explain why not all microbes are harmful.

A

Some microbes are beneficial. For instance, E. coli bacteria populate the human gut and help break down fiber in the diet. Some foods such as yogurt are formed by bacteria.

77
Q

You already know that ribosomes are abundant in red
blood cells. In what other cells of the body would you
find them in great abundance? Why?

A

Ribosomes are abundant in muscle cells as well because muscle cells are constructed of the proteins made by the ribosomes.

78
Q

What are the structural and functional similarities and
differences between mitochondria and chloroplasts?

A

Both are similar in that they are enveloped in a double membrane, both have an intermembrane space, and both make ATP. Both mitochondria and chloroplasts have DNA, and mitochondria have inner folds called cristae and a matrix, while chloroplasts have chlorophyll and accessory pigments in the thylakoids that form stacks (grana) and a stroma.

79
Q

In the context of cell biology, what do we mean by form
follows function? What are at least two examples of this
concept?

A

“Form follows function” refers to the idea that the function of a body part dictates the form of that body part. As an example, compare your arm to a bat’s wing. While the bones of the two correspond, the parts serve different functions in each organism and their forms have adapted to follow that function.

80
Q

Why are plasma membranes arranged as a bilayer rather than a monolayer?

A

The plasma membrane consists of phospholipids whose hydrophilic heads interact with water which is present both inside and outside the cell whereas the hydrophobic tails do not prefer the aqueous medium. This causes the spontaneous arrangement of the phospholipids into a bilayer.

81
Q

In your opinion, is the nuclear membrane part of the
endomembrane system? Why or why not? Defend your
answer.

A

Since the external surface of the nuclear membrane is continuous with the rough endoplasmic reticulum, which is part of the endomembrane system, then it is correct to say that it is part of the system.

82
Q

What are the similarities and differences between the
structures of centrioles and flagella?

A

Centrioles and flagella are alike in that they are made up of microtubules. In centrioles, two rings of nine microtubule “triplets” are arranged at right angles to one another. This arrangement does not occur in flagella.

83
Q

How do cilia and flagella differ?

A

Cilia and flagella are alike in that they are made up of microtubules. Cilia are short, hair-like structures that exist in large numbers and usually cover the entire surface of the plasma membrane. Flagella, in contrast, are long, hair-like structures; when flagella are present, a cell has just one or two.

84
Q

Describe how microfilaments and microtubules are
involved in the phagocytosis and destruction of a
pathogen by a macrophage.

A

The plasma membrane of macrophages extends to engulf the pathogen which is due to the remodeling of the microfilaments or actin filaments. Once the phagosome pinches off the plasma membrane and enters the cytoplasm, it is transported via microtubules to lysosomes.

85
Q

Compare and contrast the boundaries that plant,
animal, and bacteria cells use to separate themselves
from their surrounding environment.

A

Bacteria, animal cells, and plant cells have a cell membrane that separates them from the surrounding environment. Bacteria and plant cells also have a cell wall that animal cells lack.

86
Q

How does the structure of a plasmodesma differ from
that of a gap junction?

A

They differ because plant cell walls are rigid. Plasmodesmata, which a plant cell needs for transportation and communication, are able to allow movement of really large molecules. Gap junctions are necessary in animal cells for transportation and communication.

87
Q

Explain how the extracellular matrix functions.

A

The extracellular matrix functions in support and attachment for animal tissues. It also functions in the healing and growth of the tissue.

88
Q

Pathogenic E. coli have recently been shown to degrade
tight junction proteins during infection. How would
this provide an advantage to the bacteria?

A

Disruption of the tight junctions will allow paracellular transport of the bacteria, bacterial-derived lipopolysaccharides (LPS), and luminal bacteria. This can lead to LPS entering systemic circulation and causing disease.