Lecture 6 Flashcards
What is the simplest collection of matter that can be alive?
cells
True or False: all cells are related by their descent from earlier cells
True
What are the common features that all cells have?
Plasma membrane, Semifluid substance called cytosol, DNA (includes genes), and ribosomes
Where is cytosol?
In the cytoplasm
Describe prokaryotes compared to eukaryotes(5).
Eubacteria and archaea, smaller, less complex, no true nucleus, singular circular chromosome
Describe Eukaryotes compared to Prokaryotes (6).
Single-celled or multicellular
larger
more complex
true nucleus
linear chromosomes
membrane-bound organelles
What is a plasma membrane?
a selective barrier that allows sufficient passage of oxygen, nutrients, and waste to service the volume of every cell
What determines the size of a cell?
metabolic requirements set the upper limits on the size of cells
What happens as a cell increases in size?
its volume grows proportionally more than its surface area
What does the inside of a eukaryotic cell have?
internal membranes that divide the cell into compartments (the organelles)
How can you visualize cells?
Through a microscope
How does a light microscope work?
visible light is passed through a specimen and then through the glass lenses
The lenses refract the light so that the image is magnified
How can you view things smaller than a cell?
Electron Microscope
Who was June Almeida?
gifted electron microscopist
first to produce the image of a coronavirus
studied rubella, hep B, and HIV
pioneered using the electron microscope to diagnose viral diseases
Study cell structure image
.
What is contained in the nucleus?
most of the cells genes
What is the function of the nuclear envelope?
encloses the nucleus, separating it from the cytoplasm
What is the structure of the nuclear envelope?
double membrane; each membrane consisting of a lipid bilayer
DNA + Protein=____
chromatin
Where is the nucleolus located?
within the nucleus
What is the function of the nucleolus?
ribosomal RNA synthesis and ribosome assembly
What are ribosomes made up of?
ribosomal RNA (rRNA) and protein
What is the function of ribosomes?
carry out protein synthesis (take instructions from mRNA and turn into protein) in two locations
Where are ribosomes located?
in the cytosol (free ribosomes)
on the outside of the endoplasmic reticulum or the nuclear envelope (bound ribosomes) (Rough ER)