Cell structure Flashcards
Cell wall and cell membrane
Forms outer layer on Plants, fungi and bacteria. Cell wall is the most outer part
Cytoplasm / Cytosol
Contains organelles
Nucleus
Bounded by nuclear membrane, contains chromosomes
Cell membrane
Animal cells
What is plants cell wall made of?
Cellulose, a polysaccharide
What is bacterias cell wall made of?
Peptidoglycan, peptido refers to protein and glycan to sugar, so cell walls are made of protein and sugar
What is fungis cell wall made of?
Chitin, chitin is a polysaccharide that’s similar to cellulose
What is cell membrane made of?
Lipids, proteins
Aqueous
Water-based, inside of the cell
What does selectively permeable mean in cell membrane?
It passes some things in and out and restricts other
What are four ways that substances can cross the cell membrane?
Simple diffusion, Facilitated diffusion, Active transport, Bulk transport
What means simple diffusion?
When substances can flow naturally according to its concentration gradient. Cell membrane is lipid bilayer, simple diffusion works only if the substance in question is lipid soluble(hydrophobic) and can interact with oily barrier. Examples: oxygen, carbon, dioxide, steroid hormones and cholesterol
What means facilitated diffusion
Similar to simple diffusion, except that the molecules that cross are not hydrophobic and therefore cannot interact with the oily barrier and cannot simply cross the membrane. They need help of the proteins that make up the cell membrane to move substances across the lipid bilayer. Helper proteins form specialized channels across the membrane, the channels are highly specifis for particular substance
What means active transport?
In active transport, cell must expend energy to move something across the membrane. It can move substance across the cell membrane from are of low concentration to are of high concentration. That’s why it needs energy. It moves substances againt their concentration gradient. Active transport also relies on membrane proteins to move substances, doesnt matter if substance is hydrophobis or hydrophilic
What means bulk transport?
Implies to movement of large, bulky items across the cell membrane.
Two ways: endocrytosis(into the cell) and exocytosis(outside from the cell).
In endocytosis, the cell takes in a particle by surrounding and engulfingit within a pocket known as vesicle. Two examples of endocytosis are phagocytosis: cell eating, for example an amoeba surrounding particle of food with its pseudopods; a white blood cell ingesting a pathogen and pinocytosis(cell drinking)
Exocytosis is exact oppiste: a particle in a cell(in a vesicle) is released to the outside by fusing the vesicle with the cell membrane so the particle is spit out
In bulk transport, which way Endocytosis moves items and how ?
Into the cell, by a vesicle with phagocytosis or pinocytosis
In bulk transport, which way exocytosis moves items?
Out from the cell
Osmosis
Movement of water accross a cell membrane, down its concentration gradient. Thing to remember, waters concentration gradient is oppiste to the solutes(dissolved particles) concentration gradient
Hypertonic: cell shrinks
Hypotonic: cell swells and may burst
Isotonic: Stays the same
What does hypertonic mean?
cell placed into a solution more concentrated than the cells cytoplasm; more particles outside the cell than inside so there is less water outside the cell than inside. Water will move down its gradient from inside the cell to outside the cell and the cell will shrivel up as the water flows out.
What does hypotonic mean?
Cell placed into a more dilute solution than the cells cytoplasm. There are now fewer particles outside the cell than inside, so there is more water outside the cell than inside. Water will move down its gradient; from outside the cell to inside the cell and the cell will swell up and may burst
What does isotonic mean?
If the cell is put into a solution that is exactly the same concentration as the cell itself, cell stays the same
What is function of vacuole?
Storage of wastes and other material
What is function of Ribosomes?
Sites of protein synthesis, not bound by membrane
What is function of Smooth endoplasmic reticulum(smooth ER)
System of membrane and tubes that transports substances around the cell
