Cell Structure Flashcards
All cells have? (PCDRH)
- A plasma membrane
- Cytosol (fluid)
- Genetic material/DNA
- Ribosomes
- A high surface area:volume ratio
As cell size increases, surface area:volume ratio…
decreases
A cell size is determined by?
Limits
Lower limit: must have enough space to have DNA and all the macromolecules needed to function and survive
Upper limit: Due to the exchange of materials through the plasma membrane
What are the two fundamental classes of cells?
Prokaryotes and Eukaryotes
What are the similarities between Prokaryotes and Eukaryotes
They both have ribosomes, plasma membrane
For prokaryotes, DNA is centralized in?
The nucleiod
What are some differences between Prokaryotes and Eukaryotes?
Prokaryote: DNA is in the nucleiod, most have a rigid cell wall,
Eukaryote: Endoplasmic recticulum (rough and smooth er), Cytoskeleton, lysosome, Golgi, Nuclear envelope, nucleolus
Do prokaryotes have a cell wall on the outside of their plasma membrane?
Yes
Do prokaryotes have membrane-bound organelles?
No
What is the cell wall made up of for a Prokaryote?
Peptidoglycan
What is the protective coating made up of glycoproteins and glycolipids found in prokaryotes?
Glycocalyx
Throughout the cytoplasm are (blank) that make proteins via translation (both Prokaryotes and Eukaryotes)
Ribosomes
What is the size of a prokaryote?
1-5 um
Where is DNA centralized in Eukaryotes?
The nucleus, membrane bound by the nuclear envelope
Do Eukaryotes have cell walls?
SOME do (ex. plants and fungi)
Animals do not
What is the cell wall of a Eukaryote made up of? plant and fungi
Cellulose (plants)
Chitin (fungi)
What provides structure and support in a Eukaryote?
The cytoskeleton
Do Eukaryotes have membrane-bound organelles?
Yes
What is the size of a Eukaryote?
10-100um
What is the cytosol of a Eukaryote?
The part of the cytoplasm that is not held by an organelle (liquid)
What is the cytoplasm of a Eukaryote?
The materiam within a living cell excluding the nucleus (all the spaces between the plasma membrane and nuclear envelope)
Where did Eukaryotes come from?
Eukaryotes evolved from prokaryotes about 1.6-2 billion years ago from an archaea and bacterium
What is the endomembrane theory?
What we believed happen to create the endomembrane system
- Eukaryotes came from a heterotrophic prokaryotic cell
- The plasma membrane of a prokaryotic cell began invaginating into the cytoplasm (began folding in on itself)
- Those folds eventually separated from the plasma membrane and surrounded the DNA to form a nucleus
Differences between animal and plant Eukaryotic cells
Animal:
lysosome
microvilli
centrosome
flagellum
cytoskeleton
Plant:
cell wall
plasmodesmata
chloroplast
central vacuole
What are examples of Eukaryotic cells?
Animal cells, Fungi cells, Plant cells, Unicellular Eucaryotes (aka chlamy)
What does the nucleus contain?
DNA
What is the largest feature of the cell?
The nucleus (5um)
What surrounds the nucleus, what is it made of, what regulates the going in and out?
Nuclear envelope
Made of a double membrane of lipids
Nuclear Pores
The outer membrane of the nucleus is continuous with?
The rough ER
What is the inner membrane lined with?
The nuclear lamina, helps the nucleus retain shape, protein filaments that look like a net
What is DNA wound up into?
Chromatin (DNA + histones)
What is euchromatin?
Partially wound DNA (accessible for DNA replication and trascription (active genes)
What is Heterochromatin?
Fully wound DNA (inaccessable inactive genes)
What is inside the nucleus?
- Storage DNA
- Transcription of genes for that individual cell
What is prominent in a non-dividing nucleus?
The nucleolus
What is the nucleolus?
A spherical structure found in the cell’s nucleus whose primary function is to produce and assemble the cell’s ribosomes
What does the nucleolus produce?
Ribosomal RNA
Are ribosomes organelles?
No. They aren’t membrane-bound
Do prokaryotes have a membrane bound nucleus?
No. They have a nucleoid
What does a nucleoid contain?
Plasmids. Nonessential DNA that aids in cell function
What do both prokaryotes and eukaryotes have in common?
Ribosomes, DNA, Cell wall(for plants), plasma membrane, cytoplasm
What are transcription factors?
Switch on the transcription of other genes (turns them on and off)
