Topic 1 Cell Biology MPC Flashcards
If a Sequoia sempervirens tree is 100 m tall and a drawing of it is 100 mm tall, what is the magnification of the drawing?
x0.001
Which of the following structures does Escherichia coli have?
I. Ribosomes
II. Pili
III. Nucleus
I and II: Ribosomes and Pili
What feature do plant cells have but not animal cells? A. Plasma membranes B. Mitochondria C. Cell walls D. 80S ribosomes
C. Cell walls
Cells in the adrenal gland produce the hormone epinephrine and store it in vesicles. To release epinephrine these vesicles are carried to the plasma membrane and fuse with it. What process is occurring? A. Expulsion B. Exchange C. Excretion D. Exocytosis
D. Exocytosis
Define exocytosis
a process by which the contents of a cell vacuole are released to the exterior through fusion of the vacuole membrane with the cell membrane.
Define endocytosis
When substances are brought into the cell. The material to be internalised is surrounded by an area of cell membrane, which then buds off inside the cell to form a vesicle containing the ingested material.
What is cytokinesis?
the cytoplasmic division of a cell at the end of mitosis or meiosis, bringing about the separation into two daughter cells.
During which stage of the cell cycle are the numbers of mitochondria increased in a cell?
Interphase
What is the principal mode of division for the prokaryote Escherichia coli ?
Binary Fission
Where can 70S ribosomes be found?
Prokaryotes
Why do crop plants dry out when a field is irrigated with water contaminated by sea water?
The plants lose water by osmosis.
What is proportional to a cell’s surface area?
A. Rate of exchange of materials
The following events occur in mitosis.
X: Attachment of spindle microtubules to centromeres
Y: Movement of sister chromatids to opposite poles
Z: Supercoiling of chromosomes
What is the correct sequence of events?
Z → X → Y
Which process requires channel proteins?
A. Simple diffusion
B. Facilitated diffusion
C. Binding of hormones
D. Exocytosis
B
What feature of cell membranes allows endocytosis to occur?
Fluidity of phospholipid bilayer
Which substance is used for structure in plants?
Cellulose
Which characteristic of stem cells makes them useful for treating Stargardt’s disease?
A. They can differentiate into retinal cells.
What is the endosymbiotic theory?
Eukaryotic cells are believed to have evolved from early prokaryotes that were engulfed by phagocytosis
What organelles are suggested to have arisen via endosymbiosis?
Mitochondria and chloroplasts
Which evidence falsifies the Davson–Danielli model?
I. The presence of globular proteins within the phospholipid bilayer
II. Non-polar amino acids cause proteins to remain embedded in membranes
III. Membrane proteins remain in a fixed position inside a membrane
I and II only
Which organism has DNA located in three organelles?
A fern
What is a role of cholesterol in animal cells?
It controls membrane fluidity
Cell theory (3 beliefs)
- All living things are composed of cells
- The cell is the smallest unit of life
- Cells only arise from pre-existing cells
How does striated muscle fibres question the cell theory?
- Larger (30mm)
- Several hundred nuclei
- Cells may not function independently
