A) the negatively charged carbohydrate chains that protrude into the cytosol from glycolipids and integral glycoproteins
B) the negatively charged carbohydrate layer on the outer cell surface
C) the layer of anions aligned on the cytosolic surface of the plasma membrane
D) the large glycogen stores found in “fast” muscles
E) a mechanism of cell–cell attachment
2. Messenger RNA (mRNA)
A) carries the genetic code to the cytoplasm
B) carries activated amino acids to the ribosomes
C) is single-stranded RNA molecules of 21 to 23 nucleotides that can regulate gene transcription
D) forms ribosomes
3. Which of the following statements is true for both pinocytosis and phagocytosis?
A) Involves the recruitment of actin filaments
B) Occurs spontaneously and non-selectively
C) Endocytotic vesicles fuse with ribosomes that release hydrolases into the vesicles
D) Is only observed in macrophages and neutrophils
E) Does not require ATP
4. In comparing two types of cells from the same person, the variation in the proteins expressed by each cell type reflects
A) differences in the DNA contained in the nucleus of each cell
B) differences in the numbers of specific genes in their genomes
C) cell-specific expression and repression of specific genes
D) differences in the number of chromosomes in each cell
E) the age of the cells
5. Micro RNAs (miRNAs)
A) are formed in the cytoplasm and repress translation or promote degradation of mRNA before it can be translated
B) are formed in the nucleus and then processed in the cytoplasma by the dicer enzyme
C) are short (21 to 23 nucleotides) double-stranded RNA fragments that regulate gene expression
D) repress gene transcription
Questions 6–8
A) Nucleolus
B) Nucleus
C) Agranular endoplasmic reticulum
D) Granular endoplasmic reticulum
E) Golgi apparatus
F) Endosomes
G) Peroxisomes
H) Lysosomes
I) Cytosol
J) Cytoskeleton
K) Glycocalyx
L) Microtubules
For each of the scenarios described below, identify the most likely subcellular site listed above for the deficient or mutant protein.
6. Studies completed on a 5-year-old boy show an accumulation of cholesteryl esters and triglycerides in his liver, spleen, and intestines and calcification of both adrenal glands. Additional studies indicate the cause to be a deficiency in acid lipase A activity.
7. The abnormal cleavage of mannose residues during the post-translational processing of glycoproteins results in the development of a lupus-like autoimmune disease in mice. The abnormal cleavage is due to a mutation of the enzyme α-mannosidase II.
8. The observation that abnormal cleavage of mannose residues from glycoproteins causes an autoimmune disease in mice supports the role of this structure in the normal immune response.
Questions 9–11
A) Nucleolus
B) Nucleus
C) Agranular endoplasmic reticulum
D) Granular endoplasmic reticulum
E) Golgi apparatus
F) Endosomes
G) Peroxisomes
H) Lysosomes
I) Cytosol
J) Cytoskeleton
K) Glycocalyx
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