Cell Types

• Prokaryote

  • No membrane bound organelles

  • Different sections do different things but not super organized

  • Genetic information is free floating in the cytoplasm

  • Circular DNA

    • Plasmids contain genes that can be passed between individuals

  • Usually smaller than eukaryotes

  • Only bacteria and archaea are prokaryotes

• Eukaryotes

  • Contains membrane bound organelles

    • Endosymbiotic theory explains how organelles arose

      • Large prokaryotes swallowed smaller prokaryotes and formed symbiotic relationship

      • Mitochondria, nuclei, and chloroplasts are cited as evidence

      • Mitochondria and chloroplasts have their own DNA, smaller ribosomes * like bacteria) and double membranes

    • Help compartmentalize cell

    • Allows increased surface area for some processes and keeps them from competing
      Stuff inside only Eukaryotes

    • Nucleus- Contains genetic information

      • Contains DNA and RNA

      • Core is called the nucleolus

      • Outside of the nucleus is called the nuclear envelope

        • Nuclear envelope has pores (holes) that allow stuff in and out

• Endoplasmic Reticulum- 

  • Used to synthesize macromolecule

  • Made from nuclear envelope

• Rough E.R.- closest to the nucleus

  • Covered in ribosomes

  • Synthesizes proteins (RIBOSOMES MAKE PROTEIN!!!!!!!!!!!!!!!!!)

  • Does not protect the nucleus

• Smooth E.R.

  • No ribosomes (smooth)

  • Synthesizes lipids

  • Used in detoxification

• Golgi- 

  • Modifies and packages proteins

  • Made from E.R.

  • Made of flattened sacs

• Lysosome- 

  • Used in digestion and to break down things inside the cell

  • Made from the golgi

  • Hollow except for hydrolytic enzymes (enzymes that do hydrolysis)

• Vacuole-

  • Membrane-bound sacs that have a variety of uses

  • Most prominent is the large vacuole found in plant cells

• Mitochondria

  • Where ATP is made in eukaryotes

  • Double membrane

  • Exterior membrane is smooth and allows stuff in and out

  • Interior membrane is very folded! (cristae)

    • Increases surface area for electron transport chain

    • Interior fluid is where krebs cycle occurs (intercellular matrix)

  • Evidence for endosymbiotic theory

• Cilia and Flagella

  • Used for movement

  • Powered by ATP made by cellular respiration

  • Flagella- a swimming tail

  • Cilia- “fur” covering the outside of the cell that wiggle to move the cell

• Plant Cells

  • Have all the above parts and two additional organelles

  • Also have defined shape unlike animal cells

• Chloroplast

  • Where photosynthesis occurs

  • Used to make glucose for the plant from the sun

  • Full of the pigment chlorophyll

  • Two membranes

  • Thylakoids look like pancakes

    • Stacks are called granum

    • Location of light dependant reactions

  • Stroma- fluid inside the inner membrane

    • Location of light independent reactions

• Cell Wall (made of cellulose)

  • Found outside of the cell membrane

  • Used to provide structure and support to the cell

  • Does not control what enters and leaves the cell

• Organelles ALL cells have

• Ribosomes- 

  • Where translation occurs

  • Is an evidence of evolution 

    • Since all cells have ribosomes then they share a common ancestor 

  • Prokaryotes have a smaller ribosome than eukaryotes

• Cell Membrane

  • Allows stuff into and out of the cell

  • Made of phospholipids and proteins

    • Phospholipids have hydrophobic tails and hydrophilic heads

  • Small, non-charged particles pass freely through the membrane

  • Large and/or charged particles need help from a protein to pass through

• Cell Transport

  • Several factors impact how and how quickly things move across a membrane

    • Surface area- increase in surface area/volume ratio increase the rate of diffusion

      • Volume increases faster than surface area

      • This limits cell size

    • Polarity-

      •  Large polar molecules can’t get through a membrane without a protein

      • a-helixes can spiral through the membrane

• Concentration

  • Large differences in concentration lead to faster diffusion

  • Concentrations want to reach equilibrium

• Fluid mosaic model

  • Phospholipid bilayer acts like a “sea” of phospholipids

  • Proteins float in the membrane like icebergs

  • Phospholipids can change positions with each other and are not static

  Types of Transport

• Passive transport

  • DOES NOT USE ENERGY

  • Always moves from high concentration to low concentration

  • Osmosis and facilitated diffusion are examples

    • Osmosis is the movement of water across a membrane

      • Osmoregulation allows cells to maintain homeostasis

      • Aquaporins are tubes that allow water to diffuse faster

    • Facilitated Diffusion is passive transport that uses a protein

      • Non-polar parts of protein fit in non-polar part of the phospholipd

      • Polar parts of proteins stick to polar heads of phospholipids

• Active transport

  • Transport uses energy (ATP) AND a protein

  • Goes from low concentration to high concentration (against the concentration gradient)

    • Sodium-Potassium pump- 

      • loses 3 Na+ and gains 2 K+

      • lets the cell maintain an overall (-) environment

      • Much higher concentration of K inside the cell than outside the cell 

  • Endocytosis- absorbs large things into the cell

  • Ectocytosis- removes large things from a cell

• Tonicity

  • How much stuff is dissolved in a solution

  • Tell you how water moves

  • Hypertonic

    • Water moves INTO the solution

      • Plant cell will shrivel but keep its shape (plasmolysed) 

      • Animal cell will shrivel up

  • Hypotonic

    • Water moves OUT of the solution

      • Plant cells become turgid (full and rigid)

      • Animal cell will explode

  • Isotonic

    • Water moves INTO and OUT of the solution at the same time, no net change

• Water Potential

  • 𝛙=𝛙s+𝛙p  

  • 𝛙= Water Potential

    • Pure water is 0 everything else is negative

  • 𝛙p = Pressure potential

  • -For your test will be equal to 0 unless they say it isn’t

  • 𝛙s= Solute potential - How much stuff is dissolved in water. 

    • Adding more stuff makes it  more negative

• Solute Potential

  • Ψ s = -iCRT

    • i= the number of ions the solute breaks into (when put in water)

      • NaCl=2 

      • Sucrose=1 (doesn’t ionize in water)

    • C= molar concentration of the solution 

    • R= .0831,  (gas constant) 

    • T= Temperature in Kelvin (oC + 273)