Unit 2: Cell structure and function

Cell/plasma membrane

• the boundry for the cell

• Selectiely permiable

• under cell wall in plants

• in every cell

• made out of phospholipids

  • Tails together

  • heads out

Which organelles have their own nucleic acid

• Ribosomes

• Mitochondria

• Chloroplasts

Glycoproteins vs glycolipids

• Both are used for cell to cell communication and identification

• seperates the internal and external environments for the cell

• Glycoprotein

  • A protein with a carbohydrate attached

• Glycolipid

  • A lipid with a carbohydrate attached

endosymbiotic theory

• the theory that mitochondria and cyanobacteria were absorbed by eukaryotic cells and then stayed there and duplicated with them since it benefitted both of them

• Mitochonria went in first since all cells have mitochonri

Cell area to volume ratio and cell size

• When cells are too large, they have negatives that cause cell efficiency to be bad

• When a cell grows, the surface area to volume ratio decreases, which is bad

• Cons

  • Too large cell volume for transport from out of cell to center of cell

  • Plasma membrane not big enough to support transport needed

  • Cytoplasm needs too many nutrients, which is not sustainable

• SURFACE AREA TO VOLUME RATIO SHOULD BE HIGH

• Microvilli are good for increasing surface area

What can go through the plasma membrane without a protein/assistance

• small hydrophobic (nonpolar)w molecules

  • o2

  • oc2

• small uncharged polar molecules

  • even tho polar is small enough to go through

  • h20

what can not go through plasma membrane without assistance

• larger polar hydrophilic moleucels

• ions

simple diffusion

• Passive

• No energy

• Small non polar molecules with the concentration gradient

Facilitated diffusion

Passive

No energy

small polar molecules going through a transport protein with the concentration gradient

active transport

• energy involved

• Bulky molecules or molecules traveling against the concentration gradient

endo/exocytosis

active transport

Moving bulk items or large quantities into or out of the cell

osmolarity (types)

• The concept of dealing with water osmosis

• isotonic

  • A solution is isotonic when there is equal movement of water going in and out of the cells

  • Cells remain the same size

• hypertonic

  • When the solute concentration outside of the cell is larger than inside the cell, this causes the water in the cell to rush out, causing it to be flaccid

  • smaller cell

• Hypotonic

  • When the solute concentration inside the cell is larger than outside the cell

  • This causes water to rush into the cell causing it to grow and potentially burst

Water potential

• Water potential energy is the energy water has because of two main things:

  • How pure it is (if there’s stuff like salt in it, the energy goes down)

  • Pressure on it (if you squeeze or push water, the energy goes up)

• 👉 If something has more water potential than another thing, it means it has more free energy to move — water will want to leave it.

  👉 If something has less water potential than another thing, it has less free energy — water will want to enter it.

endoplasmic reticulum

• makes up more than half of the total membrane structure in many cells

• network of membranes and sacs whose internal area is called the cisternal space

• Smooth ER

  • synthesis of lipids

  • detoxification of drugs and posions

• Rough ER

  • Has associated ribosomes on it that make it rough under the microscope

  • proteins made in the rough ER are usually secreted by the cell

  • These proteins are put into transport vesicles and move to the Golgi
    

nucleous vs nucleolus and what are they in

🔹 Nucleus

• The big central organelle in a cell.

• Holds DNA (your genetic info).

• Controls everything the cell does (like the brain of the cell).

• Found in eukaryotic cells (plant and animal cells).

🔹 Nucleolus

• A small dense spot inside the nucleus.

• Makes ribosomes (which build proteins).

• Kind of like a factory inside the “brain.”

Only in eukaryotic cells

nucleoid

• genetic info place in prokaryotics

golgi apparatus

• stores, modifies and sends proteins that come from the rough ER

• cis face recieves and trans face sends

cytoskeleton

• network of protein fibers that run throughout the cytoplasm where it is responsible for support, motality and regulation

• three types

  • Microtubules

    • made of tubulin

    • largest

    • shape, support, and a railway for motor proteins

    • separate chroatids

  • microfilaments

    • made of actin

  • Intermediate filaments

    • Maintain shape

sodium potassium pump

• Sodium out of cell and potassium in

• needed for nerve transmission