W1-lecture 2: Structure and function Flashcards
What are the properties of all cells?
Metabolism Growth Evolution
What are the properties of some cells?
Differentiation Communication Genetic exchange Motility
T or F : There is an advantage of being small because your surface-to-volume ratio is higher.
T
What are the building units of the cytoplasmic membrane
constructed from either phosphoglycerol diethers, which have C20 side chains (called a phytanyl group) or diphosphoglycerol tetraethers (C40 side chains, called a biphytanyl group)
What stabilize the membrane in : animal cells, fungi and plant cells (and protozoans)
Animal : Cholesterol Fungi : Ergosterol Plan cells and some protozoans: Stigmaterol
T or F : In bacteria and archaea, sterols are almost always absent.
T, the membrane is stabilize by hopanoids in bacteria
What stabilize the membrane in bacteria
hopanoids (sterol life structure)
in procryotes, the ribosomes subunits are : ___S and ___S
30 + 50 = 70S
in eucaryotes, the ribosomes subunits are : ___S and ___S
40 + 60 = 80S
What is the difference between a cell wall and a membrane?
The main difference between cell wall and cell membrane is, cell membrane is present in all cells but cell wall is only present in plants, bacteria, fungi and algae. It is not present in the Protozoa and animal cell. Cell wall covers the cell membrane, which is a partially permeable membrane.
What are the differences between the layer of the archea and the bacteria?
1- the hydrophobic lipid in archaea is not a fatty acid it is repeated units of isoprene 2- the link between the hydrophobic part anf the glycerol is an ether in the case of archaea instead of an ester 3- Can form a bi-layer or a mono-layer in the case of archaea
What is the name of the major phospholipid found in bacteria?
Phophatidylethanolamine
What type of linkage link the phosphoglycerol and the hydrophobic portion (phyntanyl)
ether linkage as opposed to a ester linkage in the case of bacteria and eukaryotes
What are the three functions of the membrane?
1- Permeability barrier 2- Protein anchor 3- Energy conservation (for archae and bacteria)
What is composed the lipid portion in the bi-layer of archaea?
Isoprene units (5 carbons)
How many carbons is there in a phyntanyl group?
20Carbons
What are the three types of phosphoglycerol that you can find in the membrane of archaea?
1- Phosphoglycerol diether 2-Diglycerol tetraethers 3-Crenarchaeol
T or F : protozoan’s cell wall is made of cellulose.
F, the protozoans don’t have a cell wall.
T or F : animal’s cell wall is made of polysaccharides
False, they don’t have a cell wall (extralayer over the cell membrane)
What is made the cell wall of :
1- Plants, algea :
2- Fungi :
1- Plants, algea : cellulose (polymers of glucose)
2- Fungi : cellulose or chitin (polymers of n-acetylglucosamine).
What is the universal hallmark of the eukaryotic cells?
presence of a enclosed nucleus
What is the heterochromatin?
Densely packed, low level of transcription way of compacting compacting the nucleosomes (4 histones and the DNA strand around it)
What is the euchromatin?
Loosely packed, actively transcribed way of compacting the nucleosomes (4 histones and the DNA strand around it)
What is the name of the ribosome rich part of the nucleus?
nucleolus
What is the name of the organelle that is a network of membranes continuous with the nuclear membrane?
the endoplasmic reticulum
What is the function of the golgi body?
The Golgi body is a set of membrane compartments involved in further processing of proteins and their distribution. Proteins are packaged in vesicles and transported to where they are required.
What is the name of the invagination of the membrane in the mitochondria?
Cristea.
What is the equivalent of the mitochondria in phototrophic eukaryotes
The chloroplast.
Where are contains the enzymes and pigments that harvest light energy and the membrane-bound ATPases that uses this energy to producde ATP
Thylakoids inside the chloroplast
Where is the site of the calvin cylce, the assimilation of CO2 and biosynthesis in the phototrophic eukaryotes (be precise)
The stroma of the choloroplasts.
Where are found the proteins that harvest light energy in the photosynthetic prokaryotes?
They are found in the cytoplasmic membrane.
T or F : the choloplast and the mitochondria came from the engulfing of archaea a long time ago. (endosymbiotic theory)
False, it came from the engulfing of the bacteria.
Name three structure of the cytoskeleton in eukaryotes
- microtubules
- actin filament
- intermidiate filaments
What are the single proteins that make the microtubules?
alpha and beta tubulin
What are the single proteins that make the actin filaments?
actin
What are the single proteins that make the intermidiate filament?
keratin, desmin and vimentin
name the cytoskeleton parts
What is the role of the microtubules?
- Serves has highway for the transport of organelles
- Maintain the cell shape by resisting compression (push)
- Assist formation of cell plate during plant cell division
- Moves cells via flagella and cillia.
what is the name of the proteins that makes the link between the microtubules and the transport vesicles
kinesin and dynein.
What is the function of the actin filaments
- Maintain cell shape by resisting tension
- move cells via muscle contraction or cell crawling
- Divide cells into two
- move organeles and cytoplasm in plants fungi and animals
What are the functions of the intermidiates filaments?
- Maintain the cell shape by resisting the tension
- Anchor nucleus and some organelles
How many microtubules is contained in a flagella or cilia?
9 pairs around a central pair of microtubules. 20 microtubules in total.
What is the protein that uses ATP and drives the motility in the flagella and cilia.
Dynein
