Cells and Tissues
Cells are composed of their cytoplasm, which includes the cytosol and organelles; the nucleus and the surrounding plasma membrane. You should know that the plasma membrane is a double layer of phospholipid molecules and that these molecules have a hydrophilic end and a hydrophobic end. The plasma membrane contains proteins including the ATPase (the sodium-potassium pump) which moves sodium ions out of the cell while moving potassium ions into the cell.
You should know the names and function of some of the organelles. For example you should
know that mitochondria produce ATP and that ribosomes synthesise proteins from amino acids. You will become familiar with the names of many cells. Often a word can be recognised as the name of a cell because it ends in “-cyte” or, if it is an immature cell, by ending in “-blast”. Four major types of tissue are identifi ed in the body:
epithelial, connective, muscle and neural tissues. Of course there are many subtypes within these categories. For example epithelial tissue may be squamous, cuboidal, columnar or glandular. Muscle may be skeletal, smooth or cardiac. Connective tissue is quite varied and you should be aware of the many different
examples of tissue that are categorised as “connective”. For example, blood, bone, dermis, cartilage and tendon are all connective tissue.
Martin Caon
Examination Questions and Answers in Physiology
Multiple Choice Questions
- What are the major types of tissue in the body?
A. nervous, muscle, epithelial, connective.
B. squamous, cuboidal, columnar, transitional.
C. osteocytes, chondrocytes, leucocytes, adipocytes.
D. protein, adipose, cartilage, osseous.
Answer is A: choice C refers to cell types; B is a list of epithelial tissue. Protein is applied to molecules. - Which of the following is NOT one of the organelles within a cell?
A. desmosome
B. endoplasmic reticulum
C. mitochondrion
D. golgi apparatus
Answer is A: desmosome (despite having the suffi x “-some”) are not within the cell. They are structures that join adjacent plasma membranes to each other. - Which list contains the main body tissue types?
A. glandular, connective, osseous, nervous
B. epithelial, nervous, connective, muscle.
C. endothelial, connective, muscle, cartilaginous
D. epithelial, cartilaginous, muscle, glandular
Answer is B: the terms osseous, glandular and cartilaginous disqualify the other choices. - The process of “diffusion” through a membrane may be described by which of the following?
A. the movement of ions and molecules away from regions where they are in high concentration towards regions where they are in lower concentration.
B. the use of energy from ATP to move ions and small molecules into regions where they are in lower concentration.
C. the plasma membrane engulfs the substance and moves it through the membrane.
D. the use of energy from ATP to move water molecules against their concentration gradient.
Answer is A: the choices with ATP are nonsense. While choice C refers to endocytosis. - The process of “active transport” through a membrane may be described by which of the following?
A. the movement of ions and small molecules away from regions where they are in high concentration.
B. the use of energy from ATP to move ions and small molecules into regions where they are in lower concentration.
C. the plasma membrane engulfs the substance and moves it through the membrane.
D. the use of energy from ATP to move ions and small molecules against their concentration gradient.
Answer is D: energy (ATP) is required to force molecules against their concentration gradient. - Which of the following is the smallest living structural unit of the body?
A. atom
B. molecule
C. organelle
D cell
Answer is D: the cell is smallest structural unit that is deemed to be alive. - Which of the following enables ions such as sodium to cross a plasma membrane?
A. phospholipid bilayer
B. peripheral proteins
C. integral proteins
D. desmosomes
Answer is C: one function of integral protein in the PM is to form channels to allow for the passage of ions. - Cell membranes can maintain a difference in electrical charge between the interior of the cell and the extracellular fl uid. What is this charge difference called?
A. excitability
B. the membrane potential
C. the action potential
D. the sodium-potassium pump
Answer is B: the inside of a cell is negative while the exterior side of the membrane is positive. This difference in charge constitutes a difference in electrical potential (or voltage), known as the resting membrane potential. An action potential is generated when the membrane is stimulated and the potential reversed. - The resting membrane potential of a cell is the consequence of which of the following concentrations of ions?
A. High K + and Cl − outside the cell and high Na + and large anions inside the cell.
B. High K + and Na + outside the cell and high Cl − and large anions inside the cell.
C. High Cl − and Na + outside the cell and high K + and large cations inside the cell.
D. High Ca 2+ and Na + outside the cell and high K + and large cations inside the cell.
Answer is C: These ionic species are largely responsible for the membrane potential (cations are negative ions). While there is a higher concentration of Ca outside the cell than inside, there are fewer Ca than Cl ions. - What is one function of mitochondria? To
A. produce enzymes to break down molecules
B. produce molecules of ATP
C. hold adjacent cells together
D. allow passage of molecules through the plasma membrane
Answer is B: Mitochondria are organelles within which ATP is made. - Membrane proteins perform the following functions EXCEPT one. Which One?
A. form the glycocalyx
B. act as receptor proteins
C. form pores to allow the passage of small solutes
D. behave as enzymes.
Answer is A: the glycocalyx refers to molecules in the plasma membrane that have a carbohydrate chain attached (prefi x “glyco-”). - Facilitated diffusion differs from active transport because facilitated diffusion:
A. requires energy from ATP
B. moves molecules from where they are in lower concentration to higher concentration
C. moves molecules from where they are in higher concentration to lower concentration.
D. involves ions & molecules that pass through membrane channels.
Answer is C: diffusion always refers to movement from high to low concentration (without energy expenditure). Facilitated refers to the assistance provided by a transport molecule that is designed for the purpose. - Which of the following is NOT a connective tissue?
A. blood
B. mesothelium
C. fat
D. tendon
Answer is B: mesothelium is simple squamous epithelium that is found in serous membranes. - The cells that are found in tendons are called:
A. osteocytes
B. adipocytes
C. haemocytoblasts
D. fibroblasts
Answer is D: Simple Squamous. A single layer of fl at (squashed) cells so diffusion through the layer takes place easily. Lines heart, lymph & blood vessels (known as endothelium). Called mesothelium when in serous membranes. - Which one of the following terms best describes the structure of the cell membrane:
A. fl uid mosaic model
B. static mosaic model
C. quaternary structure
D. multilayered structure
Answer is A: “fl uid” implies the structure can move and change (not like a brick wall); mosaic refers to the presence of proteins scattered among the glycolipids. - Which one of the following terms best describes a phospholipid. It consists of a:
A. polar head and polar tail
B. non-polar head and a polar tail
C. polar head and non-polar tail
D. non-polar head and a non-polar tail
Answer is C: polar = hydrophilic head of phosphate (which can dissolve in the aqueous extracellular solution because water molecules are polar); non-polar = hydrophobic tails of lipid, which being non-polar, cannot dissolve in aqueous solutions. - One of the functions of integral proteins in cell membranes is to:
A. maintain the rigid structure of the cell
B. support mechanically the phospholipids
C. interact with the cytoplasm
D. form channels for transport functions
Answer is D: some proteins form channels which allow molecules and ions to enter the cell. - Which one of the following best describes what a cell membrane consists of?
A. lipids, proteins, ribosomes
B. lipids, cholesterol, proteins
C. cholesterol, proteins, cytoplasm
D. lipids, proteins, cytoplasm
Answer is B: these are the three major constituents. Ribosomes and cytoplasm are found inside the cell. - Which one of the following organelles is considered as the “energy producing”
centre of the cell?
A. rough endoplasmic reticulum
B. Golgi apparatus
C. mitochondria
D. ribosomes
Answer is C: mitochondria are where ATP molecules are produced from glucose. - What is the major function of lysosomes? They:
A. package proteins
B. detoxify toxic substances
C. catalyse lipid metabolism
D. digest unwanted particles within the cell
Answer is D: the prefi x “lys-” refers to the ability to alter molecules by dividing them into smaller pieces. - What is the purpose of the “sodium/potassium pump”
A. to perform endocytosis.
B. to move sodium and potassium by facilitated diffusion.
C. to perform bulk transport through the plasma membrane.
D. To produce a concentration gradient for sodium ions
Answer is D: a concentration gradient is set up by the use of energy to move Na ions to where they are in greater concentration. This requirement for energy means choice B is wrong. - Which of the following is NOT a type of cell?
A. ribosome
B. haemocytoblast
C. neutrophil
D. phagocyte
Answer is A: a ribosome is a cell organelle, not a cell type - What is the name of the mechanism that ensures that there is a higher concentration of sodium ions in the extracellular fl uid than in the intracellular fl uid?
A. Facilitated diffusion
B. The sodium-potassium pump
C. Secondary active transport
D. Osmosis
Answer is B: the “pump” exchanges Na for K and uses energy from ATP to function. - What is the name given to the type of transport where glucose or an amino acid binds to a receptor protein on the plasma membrane, which then moves the molecule into the cell without the expenditure of energy?
A. facilitated diffusion
B. bulk transport
C. secondary active transport
D. active transport
Answer is A: the membrane protein facilitates the entry into the cell. No energy is expended so it is not active transport. - What is the name given to the movement of glucose or amino acids from the gut into the cells lining the gut, when they bind to a transport protein that has also bound a sodium ion. The sodium ion is entering the cell along its concentration gradient.
A. facilitated diffusion
B. the sodium potassium pump
C. active transport
D. secondary active transport
Answer is D: the sodium ion was transported out of the cell with the use of energy in order to set up the sodium concentration gradient. This gradient then allows other molecules to enter the cell along with sodium’s re-entry. This is active (because energy used), but secondary as it occurs as a result of the previous active transport event. - Mitochondria produce which of the following?
A. ATP
B. DNA
C. RNA
D. proteins
Answer is A: adenosine triphosphate (ATP) - Why does the plasma membrane of a cell present a barrier to the movement of electrolytes through it?
A. There are no channels in the membrane for the passage of electrolytes.
B. Electrolytes are not soluble in the lipid of the membrane.
C. Electrolytes are too large to pass through membrane channels.
D. Membrane proteins electrically repel charged particles.
Answer is B: electrolytes, being charged particles are not able to dissolve their way through the lipid plasma membrane (which is non-polar). Hence it is a barrier to them. - Which of the following statements about “leak channels” in the plasma membrane is correct?
A. Proteins that form these channels bind to solutes to allow them to pass into the cell.
B. They are passageways formed by proteins to allow water and ions to move passively through the membrane.
C. They allow small ions and molecules to move between adjacent cells.
D. They are formed by glycoprotein and proteoglycans to allow hormones to enter cells.
Answer is B: this is the defi nition of leak channels. They may be “gated” which means shut until stimulated to open. J refers to facilitated diffusion. - What are the primary types of body tissue?
A. connective tissue, blood, muscle tissue, nervous tissue, epithelial tissue.
B. muscle tissue, osseous tissue, epithelial tissue, nervous tissue, blood, connective tissue.
C. nervous tissue, epithelial tissue, muscle tissue, connective tissue
D. epithelial tissue, connective tissue, adipose tissue, muscle tissue, nervous tissue.
Answer is C: These are the four primary types. Blood is not a “type’ of tissue. - Epithelial and connective tissue differ from each other in which of the following characteristics?
A. epithelial tissue contains fi bres but connective tissue does not.
B. connective tissue is avascular but epithelial tissue is well-vascularised.
C. cells in epithelial tissue are closely packed, whereas in connective tissue they are not.
D. connective tissue includes tissue that makes up glands, but epithelial tissue does not occur in glands.
Answer is C: The other choices are not correct. - Which of the following is a component of the plasma membrane of a cell?
A. plasma
B. glycolipid
C. plasma proteins
D. cholesterol
Answer is D: despite the term “plasma” A & C are wrong. And it is phospholipids, not glycolipids that occur in the membrane. - What term is used to describe the movement of dissolved particles along (or down) their concentration gradient?
A. endocytosis
B. active transport
C. osmosis
D. diffusion
Answer is D: Following the concentration gradient is a passive process. Choice C applies only to water molecules. - Which of the following molecules cannot pass through the plasma membrane?
A. water molecules
B. non-polar molecules
C. amino acid based hormones
D. fat-soluble molecules
Answer is C: These hormones are not lipid soluble and too large to pass through channels. - Which of the following is a connective tissue?
A. pancreas
B. spinal cord
C. muscle
D. blood
Answer is D: blood contains cells separated by a liquid matrix. Choices A & B are epithelial and nervous tissues. - Which of the following is an epithelial tissue?
A. adipose tissue
B. the adrenal gland
C. the heart
D. blood
Answer is B: the adrenal gland is glandular epithelial tissue. - What is the major component of the plasma membrane of a cell?
A. phospholipid
B. glycolipid
C. integral protein
D. cholesterol
Answer is A: cholesterol and proteins are also present in the plasma membrane but as more minor components. - Which one of the following is NOT a function of membrane proteins?
A. they form a structure called a glycocalyx
B. they attach cells to each other
C. they form passageways to allow solutes to pass through the membrane
D. they from receptors which can bind messenger molecules
Answer is A: the glycocalyx is thought of as membrane carbohydrates. - Facilitated diffusion through a membrane involves which of the following scenarios?
A. the diffusion of water through a selectively permeable membrane along its concentration gradient.
B. the movement of a molecule against its concentration gradient with the expenditure of energy
C. the plasma membrane surrounding (engulfi ng) the molecule & the molecule moving into the cell.
D. a molecule binding to a receptor which moves the molecule through the membrane without the expenditure of energy
Answer is D: facilitation is by binding to a membrane protein. - The diffusion of water through a membrane is referred to as
A. secondary active transport
B. bulk transport
C. osmosis
D. endocytosis
Answer is C: osmosis is a word that is reserved for the movement of water through a membrane. - What is the tissue that covers the body surface and lines internal tubes called?
A. epithelial tissue
B. connective tissue
C. glandular epithelium
D. muscle tissue
Answer is A: epithelial tissue has one surface “open” to the exterior or to the contents of the tube. - Which of the following is true for connective tissue?
A. it consists of cells, a basement membrane and intercellular matrix
B. its cells are closely packed and held together by protein fi bres.
C. it has a high rate of cell division and no blood supply
D. it is made of cells, protein fi bres and ground substance
Answer is D: Connective tissue includes fi bres and cells which are not closely packed. - The cell membrane’s resting potential (about −70 mV inside with respect to the
outside) is due mainly to which of the following mechanisms?
A. The sodium potassium pump.
B. The diffusion of cations and anions through the membrane along their concentration gradients.
C. The diffusion of sodium and potassium across the cell membrane.
D. The presence inside the cell of anions too large to passively cross the cell membrane.
Answer is A: The ATPase pump shifts 3 Na + out of the cell and 2 K + into the cell. This disparity in positive charge is the major infl uence on the resting potential.