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1
A cell can be divided into three principal parts: the cell (plasma) membrane, the cytoplasm and organelles, and the nucleus.
A)True
B)False
2
The cell membrane is also known as the plasma membrane.
A)True
B)False
3
The cytoplasm is the fluid portion of the cytosol.
A)True
B)False
4
The variety of specialized functions and selective transport properties that are characteristic of the membrane are believed to be due primarily to membrane proteins.
A)True
B)False
5
The membrane is not solid, the phospholipid and protein molecules are free to move laterally in a constantly changing mosaic pattern - often referred to as the fluid-mosaic model of membrane structure.
A)True
B)False
6
The uptake of cholesterol molecules by cells lining an arterial blood vessel is an example of endocytosis
A)True
B)False
7
In the process of endocytosis, secretory vesicles fuse with the cell membrane and release their contents into the extracellular environment.
A)True
B)False
8
In the human body, cilia are found along the basal surface of epithelial cells (the surface facing the lumen, or cavity) of the respiratory and female reproductive tracts.
A)True
B)False
9
In the human body, cilia and flagella are composed of protein microtubules arranged in a characteristic "9 + 2" pattern.
A)True
B)False
10
The jellylike matrix within a cell is known as the cytoskeleton.
A)True
B)False
11
The cytoskeleton is composed of protein fibers called microtubules and microfilaments, arranged in a complex flexible and mobile latticework.
A)True
B)False
12
Autophagy is a process involving lysosomes that destroy worn-out organelles so that they can be continuously replaced - also characterized as the "digestive system" of the cell.
A)True
B)False
13
Many more mitochondria are found in the ovum (egg cell) compared to sperm; and contain a more primitive form of DNA molecules that can transmit genetic defects from mother to child.
A)True
B)False
14
Most, if not all, organelles in the cell have a limited life span, and thus must be continuously destroyed and replaced.
A)True
B)False
15
Smooth endoplasmic reticulum would be abundant in cells that are active in protein synthesis and secretion, such as those of many exocrine and endocrine glands.
A)True
B)False
16
The phenomenon of "tolerance" to certain substances such as alcohol and certain drugs may be accompanied by increased amounts of the rough endoplasmic reticulum, particularly in liver cells.
A)True
B)False
17
Mitochondria may be able to reproduce themselves, especially in cells that require greater than normal energy outputs.
A)True
B)False
18
Small molecules may pass through the nuclear pore complexes located along the nuclear envelope by simple diffusion, but movement of larger protein and RNA molecules is a selective, energy-requiring process.
A)True
B)False
19
The expression of genes occurs in two sequential stages: first, genetic transcription and then, genetic translation.
A)True
B)False
20
Nucleoli are dark regions within the nucleus that contain DNA and code for the production of ribosomal RNA (rRNA).
A)True
B)False
21
Although DNA is the largest molecule in the cell, it has a simpler structure than that of most proteins.
A)True
B)False
22
According to the law of complementary base pairing, the number of purine bases in DNA molecules is greater than the number of pyrimidine bases in DNA.
A)True
B)False
23
Although composed of only four different types of bases, a gene extends several thousand nucleotides in length.
A)True
B)False
24
DNA is double-stranded helix, meaning there are two chains of DNA that twist about one another to form a molecule resembling a spiral staircase.
A)True
B)False
25
DNA strands spool around negatively charged histone proteins in the nucleus to form larger chromatin particles called nucleosomes.
A)True
B)False
26
Acetylation of chromatin is necessary for inactivating transcription by compacting the chromatin.
A)True
B)False
27
All types of RNA are formed from the information contained in the DNA within the nucleus.
A)True
B)False
28
Like DNA, RNA is also double-stranded.
A)True
B)False
29
The synthesis of RNA molecules from DNA is called genetic translation.
A)True
B)False
30
In the synthesis of RNA, the enzyme RNA polymerase is required to "unzip" a section of the paired DNA bases by breaking the weak hydrogen bonds and transcribing only one exposed strand of DNA.
A)True
B)False
31
The genes from DNA in the nucleolus located within the nucleus of the cell code for the specific production of transfer RNA (tRNA).
A)True
B)False
32
In humans, a pre-tRNA is produced that must be modified within the nucleus before it can enter the cytoplasm as tRNA and direct protein synthesis.
A)True
B)False
33
Segments of DNA scattered along a gene that do not participate in transcription of the genetic code, are called introns
A)True
B)False
34
Arriving in the cytoplasm, the mRNA can pass through a number of ribosomes to form a "string-of-pearls" structure called a polyribosome, or polysome, for short.
A)True
B)False
35
The sequence of three bases (a base triplet) in mRNA is called a codon, while the complementary triplet in tRNA is called an anticodon.
A)True
B)False
36
Proteins that are to be used within the cell are produced by the polyribosomes that float freely in the cytoplasm region of the cell.
A)True
B)False
37
Proteins that are synthesized for specific functions within a particular cell possess a hydrophobic leader sequence that permits the entry of these proteins into the cisterna of the rough endoplasmic reticulum.
A)True
B)False
38
The hormone, insulin is a good example of a protein molecule that is easily synthesized at the ribosome, processed by the endoplasmic reticulum, and secreted directly from the cell.
A)True
B)False
39
A stack of several flattened sacs that receive, modify, and repackage proteins into new vesicles best describes the endoplasmic reticulum of the cell.
A)True
B)False
40
"Semiconservative" means only one of the two DNA strands is needed to synthesize pre-mRNA during transcription.
A)True
B)False
41
DNA helicase is responsible for unwinding the DNA molecule prior to DNA replication.
A)True
B)False
42
The non-dividing cell exists in a part of its life cycle known as interphase - which is subdivided into G1, S, and G2 phases.
A)True
B)False
43
The "S" phase of the cell cycle refers to the secretory phase of the cell.
A)True
B)False
44
A group of proteins known as the cyclins are active during different phases of the cell cycle.
A)True
B)False
45
One very important oncogene is known as p53.
A)True
B)False
46
Apoptosis refers to cell death during which the cell swells, ruptures its membranes, and burst.
A)True
B)False
47
Necrosis refers to cell death during which the cell swells, ruptures its membranes, and burst.
A)True
B)False
48
Capsases are enzymes that when activated stimulate apoptosis within a cell.
A)True
B)False
49
At the end of the G2 phase of the cell cycle, each chromosome consists of two strands called chromatids which are joined together by a centromere.
A)True
B)False
50
In anaphase of mitosis, the chromosomes line up single file along the equator of the cell.
A)True
B)False
51
The division of the cytoplasm during telophase is called cytokinesis.
A)True
B)False
52
During mitosis, the centrosomes organize contractile filaments that consist of actin and myosin that attach to the cell membrane and help pinch the mother cell into two identical daughter cells.
A)True
B)False
53
Growth due to an increase in cell number as a result of mitotic cell division is called hypertrophy.
A)True
B)False
54
Polycythemia is defined as an abnormal increase in the number of circulating red blood cells and therefore would be an example of hypertrophy.
A)True
B)False
55
Meiosis is also known as reduction division since the daughter cells contain twenty-three rather than forty-six chromosomes.
A)True
B)False
56
Due to random shuffling of homologous pairs (one from mom and one from dad) and to crossing over that occurs during metaphase I, the gametes that are formed by meiosis have undergone genetic recombination.
A)True
B)False





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