CH 3: Cell Biology

cell

basic unit of life

three basic parts of a cell (CNC)

CELLS HAVE THESE COMPONENTS

• Nucleus

• Cell Membrane

• Cytoplasm

organelles

SPECIFIC STRUCTURES that PERFORM UNIQUE FUNCTIONS

• Typically in EUKARYOTES

  • e.g, mitochondria, ribosomes, Golgi body, ETC

cell membrane

This is OUTER LAYER of the cell that REGULATES WHAT GOES IN/OUT of the cell

• There’s a PHOSPHOLIPID BILAYER, meaning that certain molecules can diffuse or use different proteins to go in/out

• It DETERMINES WHAT GOES IN/OUT OF THE CELL

cell membrane structure

• Made of Lipids and Proteins

• Phospholipid Bilayer

• GLYCOCALYX (a combination of glycolipids and glycoproteins)

  • Glycolipids are fats that contains sugar molecules (carbohydrates) which are attached to a lipid component

  • Glycoproteins are proteins attached to the lipids outside the cell memebrane

function of cholesterol in the cell membrane

It’s used to STABILIZE THE AND HOLD THINGS TOGETHER WITHIN THE CELL MEMBRANE

• Since there are many things that happen within the cell membrane (like many cells going in/out), the cell membrane is very destabilized. In order to keep things from going crazy, the cholesterol molecule (a steroid — lipid) would help and hold things together within the cell membrane

cytoplasm

The liquid WITHIN THE CELL MEMBRANE that SUSPENDS THE ORGANELLES, ALLOW MOVEMENT of organelles and material, and MAINTAINS CELL SHAPE

leak channels

These are CHANNELS that are ALWAYS OPEN and ALLOWS SPECIFIC SUBSTANCE TO ENTER THROUGH CONSTANTLY

• e.g, K+ leak channels are always open to K+ ions (but it’s not going to allow other types of molecules to enter through because it’s specific to one substance)

ligand-gated channels

These are channels that ONLY OPENS/CLOSES WHEN LIGAND BINDS to it

• lock and key motion

• e.g, insulin-glucose ligand channel

  • insulin is the ligand that needs to bind to the channel in order for glucose to enter through the channels

    • If there’s no ligand that attaches to the protein, it’s not going to open and let things in

ATP powered pumps

These are pumps that NEED ATP to MOVE IONS/MOLECULES AGAINST CONCENTRATION GRADIENT

• e.g, Na+/K+ pumps

  • these pumps are used to maintain a certain concentration on the outside and inside of the cell in order to stay in equilibrium

  • when there’s ATP, Na+ and K+ bind to the pumps because the pumps CHANGED SHAPES, and 3 Na+ goes OUT of the cell (making the outside more electronegative) while 2 K+ goes IN the cell (making the cell more electropositive)

carrier protein

Type of proteins that ALLOW SPECIFIC MOLECULES TO ENTER THROUGH MEMBRANE based on their shape

• REGULATES WHAT GOES IN/OUT

endomembrane system

These are many organelle systems that WORK TOGETHER to CREATE, CHANGE, AND EXPORT CELL PRODUCTS

• Different organelles within the system:

  • ER

  • Golgi

  • Mitochondria

  • Nucleus

ER

This is like an EXTENSION OF THE NUCLEUS that’s INVOLVED IN PROTEIN/LIPID PRODUCTION. It contains CISTERNAE which are CANALS WITHIN THE ER

• The cisternae allows ribosomes to move through the ER

rough ER

appears rough because of ribosomes; functions in the synthesis and transport of proteins

• There’s going to be A LOT OF ROUGH ER IN THE MUSCLES because muscles need proteins

smooth ER

no attached ribosomes; functions in the transport of lipids and DETOXIFICATION

• lots of smooth ER in the liver because it’s more involved in detoxification

ribosomes

function in protein synthesis; found in cytoplasm and ER; composed of protein and RNA; help produce proteins; made in the nucleolus

golgi apparatus

This RECEIVES, MODIFIES, SORTS, AND PACKAGES the PROTEINS and ships it off somewhere else

• Proteins either stay inside the cell and get used OR it gets shipped out of a cell (through a transport vesicle) to get used somewhere else

mitochondria (image)

ATP MAKER; Contains the OUTER MEMBRANE, INNER MEMBRANE (with the CRISTAE and MATRIX)

• Cristae are the INFOLDINGS of the mitochondria

• Matrix are the spaces inside but between the cristae

nucleus

CONTAINS DNA; CONTROL CENTER (directs and control the cell on what to do)

• The CHROMOSOMES ARE INITIALLY CHROMATIN BEFORE CELL DIVISION

  • Chromatin would CONDENSE and turn into different chromosomes

    • NUCLEOSOMES would wrap and condense the chromatin into chromosomes

nucleolus

CREATES RIBOSOMES

chromatin

Substance IN CHROMOSOME THAT HAS DNA AND PROTEINS

concentration gradient

MOVEMENT OF ENERGY (from high to low)

endocytosis

Molecules are EATEN INTO THE CELL

exocytosis

Molecules are SECRETED OUT of the cell

• Typically going out through a vesicle

pinocytosis

LIQUID GOES IN

phagocytosis

SOLIDS GOES IN

receptor-mediated endocytosis

the cell USES SPECIFIC RECEPTORS to detect whether there are molecules in the receptor. When there are molecules that bind, it FORMS A VESICLE and takes it in 

• Receptors detects specific molecules, it surrounds the receptor and molecule into a vesicle and eat it

cell cycle

SERIES OF CHANGES a cells goes through until it reproduces

mitosis

two identical daughter cells produced

interphase (name and describe the 4 phases)

period of growth and reproduction of DNA; synthesizes

• G1 phase - CREATION OF NEW ORGANELLES TO INCREASE PROTEINS

• S phase - DNA REPLICATION HAPPENS

• G2 phase - CONTINUATION OF CELL GROWTH AND DIVISION

• G0 phase - MAINTENANCE PHASE (Cells DON’T REPLICATE in this phase)

prophase

• CHROMATIN TURNS INTO CHROMOSOMES

• SPINDLE FIBERS GROW FROM CENTRIOLES

• CENTRIOLES MOVE TO OPPOSITE SIDES/POLES OF THE CELL

metaphase

ATTACHMENT OF SPINDLE FIBERS TO CHROMOSOMES

• The CHROMOSOMES LINE UP IN THE MIDDLE OF THE CELL

anaphase

spindle fibers shorten and pSEPARATION OF CHROMOSOMES and PULLS SISTER CHROMATIDS IN OPPOSITE SIDESull chromatids apart

telophase

CREATION OF NEW NUCLEAR ENVELOPE AROUND SEPARATED CHROMOSOMES

cytokinesis

division of the cytoplasm