Which of the following organisms appear first in the fossil record?
Why is it challenging to study bacterial fossils and determine if the fossils are members of the domain archaea, rather than bacteria?
- Bacteria lack rigid structures, thus do not form fossils.
- Bacteria have rigid structures, but their fossil impression is scarce.
- Fossils of bacteria are rarely found because bacteria were not abundant in the past.
- A fossil of bacteria changes overtime due to the presence of new bacteria living on them.
Pictured are two cells along with their radius. What does cell B likely have when compared to cell A?
- smaller surface area and larger volume
- larger surface area and smaller volume
- smaller surface area-to-volume ratio
- larger surface area-to-volume ratio
Consider the shapes. The diameter of the sphere is equal to 1mm and the side of the cube is also equal to 1mm. What is the ratio of the surface to volume ratios for the sphere and the cube?
Which of the following is true regarding the surface-to-volume ratios of the cube and the sphere?
- The sphere will have a higher surface area than the cube.
- The sphere will have a higher volume than the cube.
- The sphere will have a higher surface area-to-volume ratio than the cube.
- Their surface area-to-volume ratios will be equal.
- The sphere will have a lower surface area-to-volume ratio than the cube.
What is the major consideration in setting the lower limit of cell size?
- The cell must be large enough to fight the pathogens
- The cell must be large enough to attach to a substrate.
- The lower limit should be small enough, for the cell to move in the fluid efficiently.
- The cell size must be small as to fit all the processes and structures to support life.
Which of the following structures has the same general structure in Archaea, Bacteria, and Eukarya, pointing to a common origin?
- cytoplasmic membrane
- Golgi apparatus
Why does the structure of the cytoplasmic membrane point to a common ancestor?
- The presence of a cytoplasmic membrane in every organism does not point to a common ancestry.
- The similar arrangement of phospholipids and proteins points to common ancestry.
- The lipid nature of the membrane makes it the most primitive trait.
- The similar effect of temperature on the membrane makes it the ancestral trait.
Which organelles would be present in high numbers in the leg muscles of a marathon runner?
Macrophages ingest and digest many pathogens. Which organelle plays a major role in the activity of macrophages?
You are looking at a sample under a light microscope and observe a new type of cell. You come to the conclusion that it is a bacterium and not a eukaryotic cell. What would you observe to come to this conclusion?
- the cell has a cell wall
- the cell has a flagellum
- the cell does not have a nucleus
Thiomargarita namibiensis is a large single cell organism, which can reach lengths of 700μm. The cell is classified as a bacterium. What is the main argument to justify the classification?
- This organism shows simple diffusion for the uptake of nutrients and is thus classified as a bacterium.
- This organism does not show presence of any cell organelles, and thus is classified as a bacterium.
- the existence of these organisms in long chains and pearl appearance
- The organism demonstrates characteristics of gram-negative bacteria, and thus is classified as a bacterium.
Radioactive amino acids are fed to a cell in culture for a short amount of time. This is called a pulse. You follow the appearance of radioactive proteins in the cell compartments. In which organelles and in what order does radioactivity appear?
- endoplasmic reticulum - lysosomes - Golgi body - vesicle - extracellular region
- endoplasmic reticulum - vesicles - Golgi body - vesicles - extracellular region
- Golgi Body - vesicles - endoplasmic reticulum - vesicles - extracellular region
- nucleus - endoplasmic reticulum - Golgi body - vesicle - extracellular region
With which cellular structure does the extracellular matrix interact?
- smooth endoplasmic reticulum
Which structure or structures allow bacteria to move about?
- fimbriae only
- flagella only
- flagella and fimbriae
- plasmid and capsule
Cells lining the intestine absorb a lot of nutrients. How did those cells adapt to their function?
- Cells use cilia to move nutrients to their surface.
- Cells grow much larger than adjacent cells to increase intake
- Cells are flat and thin to absorb more nutrients.
- Membrane folds called microvilli increase the surface area.