bio101- cell structure and organelles Questions
and Answers (100% Correct Answers)
Light Microscope (LM)
Ans: An optical instrument with lenses that refract (bend) visible light to magnify
images and project them onto a viewer's eye or onto photographic film
*Used to study living cells.
*Cannot give the details of an object's structure
*Can effectively magnify objects about 1000 times
*Different types of light microscopy can make the cell structures look 3D, or can be
used to specify each structure.
Magnification
Ans: The increase of an object's size compared to its actual size.
Resolution
Ans: The clarity of an object. The ability to distinguish two nearby objects as
separate.
EX. one star being seen as two stars
Cell Theory
Ans: The theory that all living things are composed of cells and that all cells come
from other cells
Electron Microscopes (EM)
Ans: Types of microscopes where beams of electrons go through a specimen onto its
surface.
*Used only on dead specimen
*High resolution allows biologists to study the internal structures of the cells
*Uses electromagnets as lenses to bend the path of electrons, magnifying and
focusing the image onto a monitor
Scanning Electron Microscope (SEM)
Ans: Studies the details of cell surfaces
, 2 Inquire through: | Professional | Confidential Support
*Electron beam scans the surface of a cell that has been coated in a film of gold.
Electrons on the surface are excited by the beam, which is detected by a device that
translates the pattern into an image
*Image looks 3D
Transmission Electron Microscope (TEM)
Ans: Studies the details of the internal structure of the cell
*Electron beam is aimed at a section of a specimen, which is stained with atoms of
heavy metal. Electrons are scattered to the more dense parts in the cell, and an image
is created by the pattern of transmitted electrons
Prokaryotic Cells
Ans: A type of cell lacking a membrane enclosed nucleus (nucleoid) and other
membrane enclosed organelles. Found in Bacteria and Archaea.
*Smaller with simple structures
*Evolutionarily older
*Outside the plasma membrane is a cell wall with a rigid structure (helps maintain
the shape). Outside the cell wall is the capsule (helps glue cell to other surfaces or
other cells)
Organelles
Ans: A membrane enclosed structure (phosphoplipid bilayer with proteins) with a
specialized function within a cell
Nuclear Envelope
Ans: A double membrane that encloses the nucleus
*Function: The envelope is perforated with pores that regulate traffic (entry and exit
of large molecules) with the cytoplasm
-Is also connected with the endoplasmic reticulum
Nucleolus
Ans: *Location: A structure within the nucleus
*Function: Ribosomal RNA is made here and then assembled with proteins imported
from the cytoplasm to make ribosomal subunits
-These subunits go back to the cytoplasm and form functional ribosomes to be apart
of protein synthesis.