Some components of cells are listed.
Cytoplasm
Nucleus
Chloroplasts
Cell Wall
Cell membrane
Which of the components could be observed using a microscope in a prepared slide of leaf epidermal cells, but not in a prepared slide of human cheek cells?
a
Components 3 and 4 only
b
Components 1, 2, and 3 only
c
Components 1 and 5 only
d
Components 2 and 3 only
The correct answer is d) Components 2 and 3 only.
Components 2 and 3, which are the nucleus and chloroplasts, can be observed in a prepared slide of leaf epidermal cells using a microscope. However, these components are not present in human cheek cells, so they cannot be observed in a prepared slide of human cheek cells.
Components 1 (cytoplasm), 4 (cell wall), and 5 (cell membrane) can be observed in both leaf epidermal cells and human cheek cells using a microscope.
Glucose is needed by all cells in order to do cellular respiration. How does glucose, a large molecule, enter cells without using cell energy?
a
using proteins pumps and ATP
b
osmosis moving against the concentration gradient
c
via channel proteins using facilitated diffusion
d
by employing active transport
The correct answer is c) via channel proteins using facilitated diffusion.
Glucose, being a large molecule, requires the help of transporter proteins to enter cells. These transporter proteins are called channel proteins and they facilitate the diffusion of glucose across the cell membrane. This process is known as facilitated diffusion and does not require the cell to use energy (ATP).
Human red blood cells contain 0.9% sodium chloride as a component of their cytoplasm. What would happen if an IV solution containing 1.5% sodium chloride is introduced into a person?
a
The red blood cells will first lose water across their cell membrane, then absorb water across their cell membrane.
b
Their red blood cells would lose water across their cell membrane and begin to shrink.
c
Their red blood cells would absorb water across their cell membrane and begin to swell.
d
The red blood cells would first absorb water across their cell membrane, then lose water across their cell membrane.
The correct answer is b) Their red blood cells would lose water across their cell membrane and begin to shrink.
When the IV solution containing 1.5% sodium chloride is introduced into a person, it creates a hypertonic environment compared to the cytoplasm of the red blood cells, which contains 0.9% sodium chloride. In a hypertonic solution, there is a higher concentration of solute (sodium chloride) outside the cells compared to inside the cells.
As a result, water will move out of the red blood cells (osmosis) to equalize the concentration of solutes on both sides of the cell membrane. This leads to the loss of water from the red blood cells, causing them to shrink or crenate.
Which of the following is NOT an example of homeostasis?
a
During rigorous exercise the heart rate increases to deliver more blood to the cells.
b
When blood glucose is high, the hormone insulin reduces blood glucose.
c
When body temperature rises, nerve impulses cause sweat glands to release more sweat.
d
As humans age, they become more susceptible to disease and cancer.
The correct answer is d) As humans age, they become more susceptible to disease and cancer.
Homeostasis refers to the body's ability to maintain a stable internal environment despite external changes. It involves processes that enable the body to regulate various physiological parameters within a narrow range. Options a), b), and c) all describe examples of homeostasis because they involve specific mechanisms that maintain stability in heart rate, blood glucose levels, and body temperature, respectively.
On the other hand, option d) does not describe an example of homeostasis. Rather, it describes a general trend that occurs as humans age, where their susceptibility to disease and cancer increases. While homeostasis helps regulate various aspects of the body, it does not prevent all diseases or the effects of aging.
If a red blood cell is placed in a HYPOTONIC solution, what will most likely happen to the cell?
a
water moves into the cell causing it to burst.
b
salt moves into the cell causing it to burst.
c
water moves out of the cell causing it to shrink.
d
salt moves out of the cell causing it to shrink
The correct answer is a) water moves into the cell causing it to burst.
When a red blood cell is placed in a hypotonic solution, it means that the solute concentration outside the cell is lower than inside the cell. In this case, water moves into the cell through the process of osmosis to equalize the concentration of solutes on both sides of the cell membrane.
As water moves into the cell, it causes the cell to swell and potentially burst, known as hemolysis. Hypotonic solutions have a higher water concentration compared to the cytoplasm of the red blood cell, resulting in an influx of water and potential bursting of the cell.
Suppose a white blood cell destroys invading bacteria by phagocytosis. Which statement best describes this process?
a
The white blood cells are using active transport, and therefore are using energy.
b
The white blood cells are using passive transport and therefore are not using energy.
c
The white blood cells are using osmosis and therefore are using energy.
d
The white blood cells are using diffusion and therefore are not using energy.