Cell Structure Flashcards
1
Q
Specialized structures in cells that perform specific functions
A
Organelles
2
Q
Examples of Organelles
A
Nucleus
Mitochondria
Ribosomes
3
Q
Jelly-like substance that holds organelles
A
Cytoplasm
4
Q
A structure that encloses the cytoplasm
A
Cell membrane / plasma membrane
5
Q
Functions of the Cell
A
Smallest units of life Cell metabolism and energy use Synthesis of molecules Communication Reproduction and inheritance
6
Q
The outermost component of a cell.
A
Cell membrane / plasma membrane
7
Q
It forms a boundary between material inside the cell and the outside.
A
Cell membrane / plasma membrane
8
Q
It acts as a selective barrier.
A
Cell membrane / plasma membrane
9
Q
Materials inside the cell are
A
Intracellular
10
Q
Materials outside the cell are
A
Extracellular
11
Q
Model used to describe the cell membrane structure.
A
Fluid-mosaic model
12
Q
What does the cell membrane contains
A
Phospholipids
Cholesterol
Proteins
Carbohydrates.
13
Q
Form a bilayer.
A
Phospholipids
14
Q
Phospholipids contain 2 regions
A
Polar and Nonpolar
15
Q
A phospholipid molecule has a polar head region that is
A
Hydrophilic
16
Q
This region is exposed to water around the membrane.
A
Polar Region
17
Q
This region is facing the interior of the membrane.
A
Nonpolar Region
18
Q
A phospholipid molecule has a nonpolar tail region that is
A
Hydrophobic
19
Q
Polar head region contains
A
Phosphate
20
Q
Nonpolar tail region contains
A
Fatty acids
21
Q
Cell membrane is made up of 2 major types of molecules
A
Phospholipids and Proteins
22
Q
Add strength and stability by limiting movement of phospholipids
A
Cholesterol
23
Q
What are the proteins that float among the phospholipids or extend from inner to outer surface of the membrane
A
Membrane channels Carrier molecules Receptor molecules Enzymes Structural supports
24
Q
The cell membrane has ___________, which allows only certain substances to pass in and out of the cell.
A
Selective permeability
25
Substances such as these are found in higher concentrations inside the cell.
Enzymes, glycogen, and potassium
26
Substances such as these are found in higher concentrations outside the cell.
Sodium, calcium, and chloride
27
Some substances, like ____________ can pass directly through the cell membrane’s phospholipid bilayer.
O2 and CO2
28
Some substances must pass through transmembrane protein channels, such as ____ through its channels.
Na+
29
True or False
The route of transport through the membrane depends on the size, shape, and charge of the substance.
True
30
Some substances require carrier molecules to transport them across the cell membrane, such as _______.
Glucose
31
True or False
All substances require a vesicular transport across the membrane.
False
Some, just some
32
True or False
The vesicle must fuse with the cell membrane for transport.
True
33
This transport does not require the cell to expend energy.
Passive membrane transport
34
This transport require the cell to expend energy, usually in the form of ATP.
Active membrane transport
35
Passive membrane transport mechanisms include _____________________________.
Diffusion, osmosis, and facilitated diffusion
36
Active membrane transport mechanisms include _____________________________.
Active transport, secondary active transport, endocytosis, and exocytosis
37
Generally involves movement of substances in a solution down a concentration gradient.
Diffusion
38
A solution is generally composed of two major parts, ______________.
Solutes and solvent
39
________ are substances dissolved in a predominant liquid or gas, which is called the solvent.
Solutes
40
Solutes are substances dissolved in a predominant liquid or gas, which is called the __________.
Solvent
41
True or False
Solutes, such as ions or molecules, tend to move from an area of higher concentration of a solute to an area of lower concentration of that same solute in solution.
True
42
This movement from high concentration to a low concentration is _____________.
Diffusion
43
A ________________ is the difference in the concentration of a solute in a solvent between two points divided by the distance between the two points.
Concentration gradient
44
True or False
The concentration gradient is said to be steeper when the concentration difference is large and/or the distance is bigger.
False
CG is steeper when
1. Concentration difference is large
2. Distance is smaller
45
_____________ can diffuse directly through the phospholipid bilayer.
Lipid soluble substances
46
________________, such as ions, can diffuse across the cell membrane only by passing through cell membrane channels.
Water-soluble substances
47
Two classes of cell membrane channels
Leak channels and gated channels.
48
Constantly allow ions to pass through.
Leak channels
49
Limit the movement of ions across the membrane by opening and closing.
Gated channels
50
Is the diffusion of water (a solvent) across a selectively permeable membrane from a region of higher water concentration to one of lower water concentration.
Osmosis
51
The force required to prevent movement of water across cell membrane
Osmotic pressure
52
True or False
Osmotic pressure depends on the difference of solution concentrations inside a cell relative to outside the cell.
True
53
A cell may be placed in solutions that are either _______________________ compared to the cell cytoplasm.
Hypotonic, isotonic, or hypertonic
54
A ________ solution has a lower concentration of solutes and a higher concentration of water relative to the cytoplasm of the cell.
Hypotonic
55
The solution has less tone, or osmotic pressure, than the cell.
Hypotonic
56
Water moves by osmosis into the cell, causing it to swell.
Hypotonic
57
If the cell swells enough, it can rupture, a process called _______.
Lysis
58
A cell immersed in an _______ solution has the same solute concentrations inside and outside the cell.
Isotonic
59
The cell will neither shrink nor swell.
Isotonic
60
The cytoplasm of a cell in a ________ solution has a lower solute concentration and higher water concentration than the surrounding solution.
Hypertonic
61
Water moves by osmosis from the cell into the hypertonic solution resulting in cell shrinkage.
Hypertonic
62
Cell shrinkage
Crenation
63
True or False
Some water-soluble, electrically charged or large sized particles cannot enter or leave through the cell membrane by diffusion.
True
64
True or False
Substances such as amino acids, glucose, and some polar molecules produced by the cell are lipid-soluble
False
Water soluble
65
Proteins within the cell membrane involved in carrier-mediated transport.
Carrier molecules
66
Carrier-mediated transport mechanisms include
Facilitated diffusion and Active transport
67
Carrier-mediated transport that does not require ATP for energy.
Facilitated diffusion
68
Carrier-mediated transport that require ATP for transport.
Active transport
69
Is a carrier-mediated transport process that moves substances across the cell membrane from an area of higher concentration to an area of lower concentration of that substance.
Facilitated diffusion
70
True or False
Because active transport's movement is with the concentration gradient, metabolic energy in the form of ATP is not required.
False
Facilitated diffusion
71
Is a carrier-mediated process, requiring ATP, that moves substances across the cell membrane from regions of lower concentration to those of higher concentration against a concentration gradient.
Active transport
72
Moves Na+ out of cells and K+ into cells.
| The result is a higher concentration of Na+ outside cells and a higher concentration of K+ inside cells.
Sodium-potassium pump
73
Uses the energy provided by a concentration gradient established by the active transport of one substance, such as Na+ to transport other substances.
Secondary active transport
74
The diffusing substance moves in the same direction as the initial active transported substance.
Cotransport
75
The diffusing substance moves in a direction opposite to that of the initial active transported substance.
Countertransport
76
Is a process that brings materials into cell using vesicles.
Endocytosis
77
Occurs when a specific substance binds to the receptor molecule and is transported into the cell.
Receptor-mediated endocytosis
78
Is often used for endocytosis when solid particles are ingested.
Phagocytosis
79
Has much smaller vesicles formed, and they contain liquid rather than solid particles.
Pinocytosis
80
Involves the use of membrane-bound sacs called secretory vesicles that accumulate materials for release from the cell.
Exocytosis
81
The vesicles move to the cell membrane and fuse, ultimately releasing the material by __________.
Exocytosis
82
Secretion of digestive enzymes is an example of
Exocytosis
83
Membrane-bound sacs that accumulate materials for release from the cell.
Secretory vesicles
84
Is a large organelle usually located near the center of the cell.
Nucleus
85
The nucleus is bounded by a______________, which consists of outer and inner membranes with a narrow space between them.
Nuclear envelope
86
The nuclear membrane contains _____________-, through which materials can pass into or out of the nucleus.
Nuclear pores
87
The nuclei of human cells contain __ pairs of chromosomes which consist of DNA and proteins.
23 pairs
88
During most of a cell’s life, the chromosomes are loosely coiled and collectively called __________.
Chromatin
89
True or False
When a cell prepares to divide, the chromosomes become tightly coiled and are visible when viewed with a microscope.
True
90
Within the nucleus are_________, which are diffused bodies with no surrounding membrane that are found within the nucleus
Nucleoli
91
True or False
There are usually only one nucleoli within the nucleus.
False
One to several nucleoli
92
Ribosomes, a type of cytoplasmic organelle, are formed within a _________.
Nucleolus
93
These ribosomal components exit the nucleus through the _________.
Nuclear pores
94
Are produced in the nucleolus.
Ribosome
95
Organelles where proteins are produced.
Ribosomes
96
Ribosomes may be attached to other organelles, such as the _________________.
Endoplasmic reticulum
97
Ribosomes that are not attached to any other organelle are called
Free ribosomes
98
Is a series of membranes forming sacs and tubules that extends from the outer nuclear membrane into the cytoplasm.
Endoplasmic reticulum
99
Is involved in protein synthesis and is rough due to attached ribosomes.
Rough ER
100
Is a site for lipid synthesis, cellular detoxification, and it stores calcium ions in skeletal muscle cells.
Smooth ER
101
Consists of closely packed stacks of curved, membrane-bound sacs.
Golgi apparatus / Golgi complex / Golgi body
102
It collects, modifies, packages, and distributes proteins and lipids manufactured by the ER.
Golgi apparatus / Golgi complex / Golgi body
103
Forms vesicles, some of which are secretory vesicles, lysosomes, and other vesicles.
Golgi apparatus / Golgi complex / Golgi body
104
Are membrane-bound vesicles formed from the Golgi apparatus.
Lysosomes
105
They contain a variety of enzymes that function as intracellular digestive systems.
Lysosomes
106
Vesicles formed by endocytosis may fuse with _____________ in order to breakdown materials in the endocytotic vesicles.
Lysosomes
107
Example of a vesicle fusing with a lysosome
White blood cells phagocytizing bacteria.
108
Are small, membrane-bound vesicles containing enzymes that break down fatty acids, amino acids, and hydrogen peroxide (H2O2).
Peroxisomes
109
Is a by-product of fatty acid and amino acid breakdown and can be toxic to a cell.
Hydrogen peroxide
110
The enzymes in _________ break down hydrogen.
Peroxisomes
111
Are small organelles responsible for producing considerable amounts of ATP by aerobic (with O2) metabolism.
Mitochondria (singular mitochondrion)
112
They have inner and outer membranes separated by a space.
Mitochondria (singular mitochondrion)
113
Mitochondria have outer membranes with a smooth contour, but the inner membranes have numerous folds, called ______, which project into the interior of the mitochondria.
cristae
114
The material within the inner membrane is the ___________ and contains enzymes and mitochondrial DNA (mtDNA).
Mitochondrial matrix
115
True or False
Cells with a large energy requirement have more mitochondria than cells that require less energy.
True
116
Gives internal framework to the cell.
Cytoskeleton
117
It consists of protein structures that support the cell, hold organelles in place, and enable the cell to change shape.
Cytoskeleton
118
Protein structures found in cytoskeletons
Microtubules, microfilaments, and intermediate filaments.
119
Hollow structures formed from protein subunits.
Microtubules
120
Perform a variety of roles, including helping to support the cytoplasm of cells, assisting in cell division, and forming essential components of certain organelles, such as cilia and flagella.
Microtubules
121
Small fibrils formed from protein subunits that structurally support the cytoplasm, determining cell shape.
Microfilaments
122
Some ________ are involved with cell movement.
Microfilaments
123
__________ in muscle cells enable the cells to shorten, or contract.
Microfilaments
124
Are fibrils formed from protein subunits that are smaller in diameter than microtubules but larger in diameter than microfilaments.
Intermediate filaments
125
They provide mechanical support to the cell.
Intermediate filaments
126
A specific type of intermediate filament is _____, a protein associated with skin cells.
Keratin
127
Is a specialized area of cytoplasm close to the nucleus where microtubule formation occurs.
Centrosome
128
It contains two centrioles, which are normally oriented perpendicular to each other.
Centrosome
129
Is a small, cylindrical organelle composed of microtubules.
Centriole
130
Is involved in the process of mitosis.
Centriole
131
Cylindrical structures that extend from the cell and are composed of microtubules.
Cilia
132
They are responsible for the movement of materials over the top of cells, such as mucus.
Cilia
133
Have a structure similar to that of cilia but are much longer, and they usually occur only one per cell.
Flagella
134
An example of a cell that has a flagella
Sperm cells each have one flagellum, which propels the sperm cell.
135
Are specialized extensions of the cell membrane that are supported by microfilaments.
Microvilli
136
They do not actively move as cilia and flagella do.
Microvilli
137
Are numerous on cells that have them and they increase the surface area of those cells.
Microvilli
138
They are abundant on the surface of cells that line the intestine, kidney, and other areas in which absorption is an important function.
Microvilli
139
Identity of a cell are determined by these
A cell’s characteristics are determine by the type of proteins produced.
The proteins produced are in turn determined by the genetic information in the nucleus.
Information in DNA provides the cell with a code for its cellular processes.
140
Contains the information that directs protein synthesis;
DNA
141
A DNA molecule consists of _________ joined together to form two nucleotide strands.
Nucleotides
142
True or False
The two strand of nucleotides are connected and resemble a ladder that is twisted around its long axis.
True
143
Each ________ consists of a 5-carbon sugar, a phosphate group, and a nitrogenous base.
Nucleotide
144
Process where information in our gene is used for protein synthesis
Gene expression
145
True or False
Each nucleotide on one DNA strand has a specific bonding pattern to another nucleotide on the opposite strand.
True
146
Is a sequence of nucleotides that provides a chemical set of instructions for making a specific protein.
Gene
147
Gene expression, which is protein synthesis, involves _____________________.
Transcription and translation
148
Involves copying DNA into messenger RNA.
Transcription
149
Involves messenger RNA being used to produce a protein.
Translation
150
Transcription takes place in the _______ of the cell.
Nucleus
151
DNA determines the structure of mRNA through _______.
Transcription
152
During _______, the double strands of a DNA segment separate, and DNA nucleotides of the gene pair with RNA nucleotides that form the mRNA.
Transcription
153
DNA contains one of the following organic bases:
Thymine, adenine, cytosine, or guanine.
154
Messenger RNA (mRNA) contains
Uracil, adenine, cytosine, or guanine.
155
DNA’s thymine pairs with RNA’s _______.
Adenine
156
True or False
DNA nucleotides pair only with any type of RNA nucleotides.
False
pair up with SPECIFIC type of RNA nucleotides
157
DNA’s adenine pairs with RNA’s ______.
Uracil
158
DNA’s cytosine pairs with RNA’s _________
Guanine
159
DNA’s guanine pairs with RNA’s _______.
Cytosine
160
Occurs in the cell cytoplasm after mRNA has exited the nucleus through the nuclear pores.
Translation
161
The mRNA attaches to a ribosome.
Translation
162
True or False
Codons (3 nucleotide bases) on the mRNA are read by anticodons (3 nucleotide bases) on transfer RNA (tRNA).
True
163
Transports specific amino acids from the cytoplasm to the ribosome-mRNA complex and initiates formation of the polypeptide chain.
Transfer RNA
164
During growth and development, __________ occurs to increase the number of cells or replace damaged or dying ones.
Cell division
165
The cell cycle includes two major phases: a nondividing phase, called _________, and a cell dividing phase, termed _______.
Interphase
Mitosis
166
During______, the DNA (located in chromosomes in the cell’s nucleus) is replicated.
Interphase
167
Replication of DNA gives two identical _______ joined at a _________; both form one chromosome.
Chromatids
Centromere
168
Each human cell (except sperm and egg) contains __ pairs of chromosomes.
23 pairs
169
The___________ contain 23 chromosomes total.
Sperm or egg cell
170
Two X chromosomes if the person is
Female
171
X and Y chromosome if the person is
Male
172
Involves formation of 2 daughter cells from a single parent cell.
Mitosis
173
Mitosis is divided into four phases:
Prophase, metaphase, anaphase, and telophase.
174
The chromatin condenses to form visible chromosomes.
Prophase
175
Microtubules, termed spindle fibers, form to assist in breaking the centromere between the chromatids and move the chromosomes to opposite sides of the cell.
Prophase
176
The nuclear membrane dissolves.
Prophase
177
The chromosomes align near the center of the cell.
Metaphase
178
The movement of the chromosomes is regulated by the attached spindle fibers.
Metaphase
179
The chromatids separate and each chromatid is called a chromosome.
Anaphase
180
Each of the two sets of 46 chromosomes is moved by the spindle fibers toward the centriole at one of the poles of the cell.
Anaphase
181
Each set of chromosomes has reached an opposite pole of the cell, and the cytoplasm begins to divide.
Anaphase
182
The chromosomes in each of the daughter cells become organized to form two separate nuclei, one in each newly formed daughter cell.
Telophase
183
The chromosomes begin to unravel and resemble the genetic material during interphase.
Telophase
184
Cytoplasm division is completed, and two separate daughter cells are produced.
Telophase
185
The process by which cells develop with specialized structures and functions is called
Differentiation
186
Termed programmed cell death, is a normal process by which cell numbers within various tissues are adjusted and controlled.
Apoptosis
187
True or False
In the developing fetus, apoptosis removes extra tissue, such as cells between the developing fingers and toes.
True
188
True or False
In some adult tissues, apoptosis eliminates excess cells to maintain a constant number of cells within the tissue.
True
189
Causes for cellular aging
```
Existence of a cellular clock
Presence of death genes
DNA damage
Formation of free radicals
Mitochondrial damage
```
190
Abnormal proliferations of cells.
Tumors
191
They are due to problems occurring in the cell cycle.
Tumors
192
Some tumors are ________ and some are (cancer).
Benign
Malignant
193
Process of the spread of malignant tumors
Metastasis
