Cell as basic unit of life lesson 3 (2 webinars )): lectures 5 and 6 Flashcards
what is the nucleolus?
dark structure inside nucleus .
where are plastids present ?
bacteria and plant cells . in plats it is responsible for photosynthesis.
is blue green algae eukaryotic or prokaryotic ?
it is prokaryotic
what are some differences between animal and plant cells ?
Golgi body in plant cell is small and formed of many units while in animal cells its a complex single unit .
plant cells lack centrosomes and centriole ( which play an important role in cell division of animal cells .
do fungi have a cell wall?
yes.
what are the main structures of bacterial , plant , and fungi cell wall?
bacteria : peptidoglycan
fungi :chitin
plant : cellulose
what is the cell membrane made out of ?
phospholipids , proteins , carbohydrates , and cholesterol (
what are the ways molecules move across cell membrane ?
diffusion :molecules moving from high concentration to low concentration across the concentration gradient across the plasma membrane , without using any energy
osmosis: movement of water across semi permeable membrane from low solute concentration to high solute concentration .(according to concentration of solute )
active transport : if cell is larger and requires energy to move across plasma membrane
phagocytosis : cell eating ( solid molecules being engulfed by cell )
pinocytosis : cell drinking ( cell engulfing fluid )
exocytosis : cell secreting its product.
who described the fluid mosaic model of the plasma membrane ?
singer and Nicolson (1974)
discuss the fluid mosaic model .
plasma membrane is formed of phosphate bilayer. phosphate head will be pointing outwards and fatty acid tail will be pointing inwards .
the phosphate heads are not fixed , they can move , they are fluid.
proteins are embedded randomly as peripheral or integrated portion of bilayer
which part of the phospholipid is hydrophilic and which are hydrophobic ?
phosphate heads are hydrophilic (polar structure )
fatty acid tail is hydrophobic
drugs are made to be fatty/ lipid soluble.
..
what does integrated and peripheral protein mean?
peripheral proteins are proteins only associated on the surface of the bilayer
integrated proteins are proteins that are across both the outer and inner layer of the bilayer
what is the function of cholesterol in the bilayer ?
it stabilizes the cell membrane .
WEBINAR 2->
FROM THIS POINT ONWARDS
why is cystic fibrosis caused?
abnormalities of one abnormal protein in phospholipid bilayer that is responsible for chlorine transportation
how does cystic fibrosis affect the teeth?
they look blue due to deposition of chlorine.
what is the protoplasm ?
living substance in cell that contains all vital products including cytoplasm and nucleus
what are the none living cell inclusions in cytoplasm ?
ergastic substance and cytoskeletal elements
what’s the cytoplasm without cell organelles called?(only fluid)
cytosol
what is the nucleus surrounded by?
double layered porous (structures can leave or enter nucleus through these pores)nuclear membrane
what is the fluid inside the nucleolus called?
karyolymph (nucleoplasm )it contains chromatin and nucleolus
what are the 2 parts of the karyolymph ?
structureless phase : nuclear sap that is made up of phospholipids , proteins , and enzymes
structural phase: is composed of chromatin network and nucleolus .
when does the chromosome take on the X shape?
when cell is in resting state it contains a thread of line (or rod)called chromatin .when the cell is dividing , in metaphase it condenses and takes on the X shape because it now has 2 sister chromatids.
what are the dark stained and light stained areas on the chromosome called?
the dark stained area is called heterochromatin . it is more condensed . it is inactive and doesn’t have a lot of genes .
the faint part is called euchromatin , it is less condensed and is genetically active
what does chromatin contain ?
DNA , histone , and some RNA
how many nucleoli does each nucleous contain ?
2-3
what is responsible for forming the nucleolus ?
nuclear organizer chromosomes .They organize themselves in such a way that the RNA of the chromatin will be condensed together and visible as nucleolus .
*which is why the main function of the nucleolus is formation of RNA
what is the main function of the nucleolus ?
synthesis of RNA
