In animal cells, hydrolytic enzymes are packages to prevent destruction of cellular components. Which of the following organelles function in this compartmentalization?
Which of the following factors would tend to increase membrane fluidity?
a great proportion of unsaturated phospholipids
Which of the following cell components is not directly involved in synthesis or secretion?
A biologist ground up some plant cells then centrifuged the mixture. She obtained some organelles from the sediment in the test tube. the organelles took up CO2 and gave off O2. The organelles are most likely
Cells can be described as having a cytoskeleton of internal structure that contributes to shape, organization, and movement of the cell. All of the following are part of the cytoskeleton except
the cell wall
Microfilaments are well known for their role of which of the following?
contracting of muscle cells, formation of cleavage furrows, ameboid movement
According to the fluid mosaic model of membrane structure, proteins of the membrane are mostly
embedded in a lipid bilayer
Ions can travel directly from the cytoplasm of one animal cell to the cytoplasm of an adjacent cell through
Which of the following is not a known function of the cytoskeleton?
to maintain a critical limit on cell size
Large numbers of ribosomes are present in cells that specialize in producing which of the following molecules?
A cell has the following molecules and structures: enzymes, DNA, ribosomes, plasma membrane, and mitochondria. It could be a cell from
a plant or animal
Which type of organelle is primarily involved in the synthesis of oil, phospholipids, and steroids?
smoother endoplasmic reticulum
Carbohydrates generally have a molecular formula
in which carbon, hydrogen, and oxygen are present in a ratio of 1:2:1.
Of the following, which is probably the most common route for membrane flow in the endomembrane system?
rough ER -> vesicles -> Gogli -> plasma membrane
Which structure is the site of the synthesis of proteins that may be exported from the cell?
Which of the following relationships between cell structures and their respective function is NOT correct?
chloroplasts: chief site of protein synthesis
Celery stalks that are immersed in fresh water for several hours become stiff and hard. Similar stalks left in a salt solution become limp and soft. From this we can deduce that the celery stalks are
hypertonic to fresh water but hypotonic to the salt solution
Which of the following types of molecules are the major structural components of the cell membrane?
phospholipids and proteins
The movement of a substance across a biological membrane against its concentration gradient with the help of energy input is which of the following?
What membrane-surface molecules are thought to be most important as cells recognize each other?
Which of the following statements is CORRECT about diffusion?
it is a passive process in which molecules move from a region of higher concentration to a region of lower concentration
The presence of cholesterol in the plasma membranes of some animals
enables the membrane to stay fluid more easily when cell temperature drops
Glucose diffuses slowly through artificial phospholipid bilayers. The cells lining the small intestine, however, rapidly move large quantities of glucose from the glucose-rich food into their glucose-poor cytoplasm. Using this information, which transport is most probably functiong in the intestinal cells?
Which of the following adheres to the extracellular surface of animal cell plasma membranes?
fibers of the extra cellular matrix
IMAGE Initially, in terms of molarity, the solution in side A with respect to that in side B is