3 Flashcards
Bio macromolecules
Carbohydrates
Lipids
Proteins
Nucleic acids
Triglyceride
Glycerol+3 fatty acids
Structure of a phospholipid
Glycerol+ 2 fatty acids+ phosphate -linked head group
Which fatty acid is liquid at room temperature
Unsaturated
Two regions of phospholipids
Hydrophilic head,
Hydrophobic tail
Function of phospholipids
Make cell membrane and membranes around organelles and vesicles
What does it mean for the cell membrane to be semi-permeable
Only lets certain things go through
Where do heads of phospholipids point?
Outward, head is charged.
Things that are charged are going to stick to or be repelled by
Importance of phospholipids
Lets you carry out different reactions in various compartments
Channel proteins
Facilitate transport across cell membrane.
Don’t require ATP
How do channel proteins work?
They get signal,
Tunnel opens up. When signal stops, they close.
Can allow electrolytes and other charged substances to move down their gradient across phospholipid bilayer
Second most abundant component in cell membrane is
Proteins
Which region of phospholipid bilayer prevents charged molecules from passing through?
Hydrophobic
What is the hydrophilic region?
Head is charged
Which substances don’t move through cell membrane easily?
Charged. Need channel proteins
Which substances move easily through cell membrane?
Uncharged small, neutral .
Pass through concentration gradient
Cholesterol role
Membrane stabilizer.
Phospholipid raft
Group of cholesterol stabilizers in one group.
Moves through membrane.
Peripheral protein
Any protein that sticks to the interior or exterior of the cell membrane.
Integral membrane protein
Completely spans the phospholipid bilayer
Ex are channel proteins
Glycoprotein
Protein with carbohydrate attached
Name tag of cell, lets immune system recognize this cell as self. Bacteria have different glycoproteins that label them as non-self
Glycolypid
Lipid with carbohydrate attached
Passive transport
Movement down the concentration gradient across the cell membrane that does not require energy.
Small uncharged particles move down concentration gradient until there’s equilibrium on both sides of plasma membrane
Cytoplasm
Cytosol+organelles inside of cell
Cytosol
Gel-like solution that houses organelles , vesicles and proteins
Steroids movement in target receptor cells
Moves down concentration gradient through cell membrane
Facilitated transport
Down concentration gradient
Uses channel proteins
Changes shape
Examples of channel proteins
Voltage gated calcium channels
Voltage gated sodium channels
Ligand gated sodium channels
Voltage gated potassium channel
Osmosis
Passive transport
Way that vast majority of water is moved in the human body.
Water moved to higher impermeable solute concentration to balance the amount of solute concentration so that concentrations are equal on both sides
Tonicity
Ability to cause a net flow of water across a semi-permeable membrane
Hypertonic solution
High concentration outside
Water leaves cells and goes into solution
Isotonic solution
Concentration is same in cells and outside
Hypotonic
Solution has less concentration than cell . Water will go to cell to dilute it and cell will burst
Example of isotonic solution
0.9 saline solution
Filtration
Passage of a solvent and dissolved substances through a membrane or filter
Transcytosis
Sequence of endocytosis
Vesicular transport through the cell and exocytosis on the other side
Active transport
Requires ATP Because it goes against the gradient
NaK pump
Resets neuron so it can be used again after hyperpolarization.
Need high Na in ECF to signal action potential so it goes in the cell to depolarize cell.
K must be high on inside and low outside.
Sodium potassium ATPase pump
Resets the concentration gradient after hyper polarization.
Pumps 3 Sodium out and two potassium in
Embedded in phospholipid bilayer
ATPase
Enzyme that breaks off potassium and releases energy. Helps pump use energy to move cations back and forth
What percentage of calories are burned by sodium potassium pumps?
25%
Types of active transport
NaK pump
Endocytosis
Exocytosis
Endocytosis
Extracellular molecules or particles enter cells
Types of endocytosis
Phagocytosis
Pinocytosis
Receptor mediated endocytosis
Phagocytosis
Cell eating
Engulfs foreign materials from extracellular fluid
Part of membrane surrounds a body
Difference between primary active transport and secondary active transport
Primary active transport directly uses energy, usually in the form of ATP, to transport molecules across a cell membrane, while secondary active transport uses the energy stored in an electrochemical gradient to drive the movement of molecules.
Pinocytosis
Cell drinking,
Cell pulls in ECF and electrolytes, nutrients
Receptor mediated endocytosis
Engulfed particles attach to receptors on membrane before endocytosis occurs.
When enough receptors are bound, it makes a vesicle
Why does Endocytosis require ATP?
Needs energy to make and move the vesicle
How do vesicles move?
Towed along cytoskeleton by motor proteins (myosins kine sins)
Need energy to tell vesicles where they need to go
Exocytosis
Substances move from cell interior to cell exterior via secretory vesicles
Active because it uses motor proteins to do things
Primary active transport
Directly uses ATP to move against concentration gradient
Secondary active transport
Move chemicals against gradients using energy but doesn’t use ATP. I stead it uses downhill gradient from ion or molecule . Uses downhill gradient from one ion or molecule to drive uphill movement of another substance
How do vesicles move along tubulin?
Myosins and kinesins change shape after receiving energy from ATP.. look like walking across tubulin of cytoskeleton. Acts like highway
Pancreatic acinar cells
Make digestive enzymes that get released into duodenum.
Help breakdown food that is partially broken down.
Make vesicles with digestive enzymes that got released into the duodenum.
Timing is important
Nucleus
Extra rich environment for the DNA. Has chromatin
Surrounded by nuclear membrane
What happens when chromatin is unwound?
Chromatin is unwound because the cell is actively transcribing genes into messenger RNA
Then
Translating mRNAs into protein
Nucleolus
Rich, nonmembrane bound region called nucleolus. Has a lot of RNA used for other processes in cell
Rough endoplasmic reticulum
Where proteins are synthesized
As proteins are synthesized, they bud off and move towards golgi apparatus
Golgi apparatus
Set of pancake structure
Modifies proteins. Folds proteins. Packages proteins for their destinations (inside or outside cell)
Free Ribosomes
Make proteins that are going to stay in cell. In cytosol or norganelles
Smooth endoplasmic reticulum
No ribosomes on surface. Makes lipids and complex carbohydrates. Detoxification reactions in cells. Especially important in hepatocytes of liver
Vacuoles
Small in animal cells, larger in plant cells. Sequester substances and waste products that we don’t want the cell exposed to.
Microfilaments
Thinnest elements of the cytoskeleton . Cell motility and changes in cell shape.
Biconcave shape of rbcs
Cytoskeleton
Cell skeleton made of structural proteins running through cytosol
Intermediate filaments
thicker than actin but thinner than microtubules. Protein filaments. Resist mechanical stress and connect other elements.
Overall shape and structure
Microtubule
Acts as highway for proteins to transport vesicles. Organize cytoskeleton. Made of tubulin
Peroxisomes
Similar to lysosome
But specialize in digesting long chain fatty acids.
Have lots of catalase which breaks down hydrogen peroxide (made by many reactions)
Lysosomes
Recycling unit of cell
Cocktail of digestive enzymes
Proteases, lipases, nucleases, amylases, very low acidic pH.
If one accidentally bursts, it can kill entire cell
Lysosomes
Centrosome
Important when cell undergoes mitosis.
Contains paired organelles called centrioles
Mitochondria
Aerobic respiration occurs. Make the majority of ATP
Have it’s own DNA. Encodes for 35+ genes
Mitochondria divide through
Binary fission. Divide like bacteria inside of the cell
Ribosomal RNA
Makes up ribosomes
Function of ribosomes
Take mRNA and call in appropriate tRNAwith right aminoacid. To build aminoacid sequence. To translate aminoacid sequence into final protein.
Made proteins usually go to golgi apparatus for final processing before they leave.
Cis face of Golgi apparatus
Faces nucleus
Trans face of Golgi apparatus
Faces away from nucleus
What happens at golgi apparatus?
1.There is transport vesicle. Buds off endoplasmic reticulum .
To cis face of golgi.
- Transport vesicles bring molecules from rough ER
- Molecules fuse with membrane & are sorted based on destination
- Molecules undergo remodeling & modifications in cisternae.
4.modified molecules are secreted out of cell or to another organelle.
Endomembrane system
Incorporates organelles that work together . The membranes for the organelles are continuous. Includes, nucleus ,ER, golgi apparatus, secretory vesicles, lysosomes and nuclear envelopes
Invagination process
Cell membrane folded in on itself to make cavities for organelles
Endosymbiotic hypothesis
Theory of how mitochondria and chloroplasts got in cell. Bacteria were pulled into eukaryotic cells and developed a symbiotic relationship over time.
Prokaryotes
No nucleus
Eukaryotic cells
Have nucleus and specialized organelles
Post-translational modifications
Modifications that happen after translation of mRNA. Help make associationd
Importance of surface area of mitochondria
Make more ATP through aerobic cellular respiration.
Parts of mitochondria membrane
Inner membrane folds called cristae
Cristae function
Give a lot more surface area for protein complexes that are important for electron transport chain
How do cristae help make more ATP?
Highly folded. Give a lot more surface area for protein complexes in the electron transport chain
- Take intermediate creations in cellular respiration process and harvest the energy off electrons that we added energy to the bonds. Collect energy and make proton gradient.
- Use energy to make H+ gradient to add a P to ADP
Where does concentration of protons build up?
Inter membrane space
Matrix
Site of oxidative phosphorylation, where ATP is produced from ADP . Inside of mitochondria
Hydrolitic enzymes
Proteins that break things down
Phagolysosome
Lysosome combined with phagocyte. Breaks down the contents of the phagocyte
Anything that involves remodeling uses this organelle
Lysosome
Tay sachs
Lysosomes are missing one type of lipase.lysosomes in brain fill up with a lipid they can’t break down
Double phospholipid bilayer
Nuclear membrane
Nuclear pores
mRNA exits the nucleus through
Cisterna
Folds in rough endoplasmic reticulum
Increases surface area for ribosomes to carry out a lot of translation and create a lot of proteins. Connected to nuclear membrane
What happens as RBCs mature
Nucleus and almost all of mitochondria are ejected as the red blood cell matures
How long do RBCs live and why?
120 days
Can’t direct own repairs. Carry O2 around body. Get worn and can lead to clots and capillaries
Body invests lots of energy in doing what to RBCs
Pulling and screening RBCs as well as making them
How much hemoglobin does one RBC carry per cell?
250 million copies
Why is oxygen needed in cells
To act as the final electron acceptor in cellular respiration
Explain the parts of cell division
Mitosis and cytokinesis
Cytokinesis
Division of cytoplasm
Mitosis
Nuclear division
Gap 1
Increase amount of cytoplasm and organelles
Grows
Synthesis
Doubles amount of DNA in prep for mitosis.
G2
Makes sure that there’s enough proteins and cytosol.. Makes sure there’s enough cellular machinery to carry out mitosis and cytokinesis
G0
Some cells freeze cell cycle and wait for a signal before entering cell cycle again. Sometimes they receive a signal that there’s problems with the cell cycle and they terminate the cell line.
Sister chromatics are created after
S-phase.
Two copies of chromosomes from mom and two copies of chromosomes from dad.
Explain cell division
Mitosis+cytokinesis
Prophase
- Nuclear membrane dissolves,chromosomes condense.
- Spindle fibers emerge from centrososmes
- Nuclear envelope breaks down
- Centrososmes move toward opposite poles
Centrosome contains
2 small organelles that start to make mitotic spindle.
Mitotic spindle function
Pulls chromosomes apart
Metaphase
Chromosomes line up at the metaphase plate,
Each sister chromatid is attached to a spindle fiber originating from opposite poles
Anaphase
Pulling chromosomes apart.
Sister chromatids become chromosomes are pulled apart.
Spindle fibers begin to elongate the cell.
Telophase
Chromosomes arrive at opposite poles and they begin to decondense
The nuclear envelope surrounds each set of chromosomes
The mitotic spindle breaks down
Spindles continue to push poles apart
Cytokinesis
A cleavage furrow separates the daughter cells or a plant plate in plant cells
Mitosis results in
2 identical daughter cells
Which proteins help drive the cell cycle
Cyclin
Signal end of one part and beginning of another
What do checkpoints in the cell cycle do
Tell cell to die through apoptosis
Check to make sure things are being made approximately
G1 restriction
Makes sure cell has grown enough to begin doubling of DNA
Checkpoint 2
Makes sure all DNA was copied appropriately
Mitosis checkpoint
Make sure chromosomes got pulled apart equally
Apoptosis
Programmed cell death
Helps eliminate unwanted cells and prevents faulty cells from replicating
Uncontrolled cell division
Cancer
Types of genes that can mutate to produce cancer
Protoncogene
Tumor suppressor gene
Cell checkpoints don’t work and cell can pick up additional mutations
Tumor suppressor gene
No tumor suppression, no brake for cancer
Protoncogene
Too activated
Tells cell cycle to go forward..gas pedal stuck down
P53
One of the most important tumor suppressor genes in body
Has multiple defense mechanisms
Pados paradox
Larger animals have more copies of p53 gene which lowers their risk of developing cancer. Does not matter if elephants have one faulty p53 because they have many that can still prevent mutations.
Li-fraumeni syndrome
Carry one good copy of p53, 90% risk of cancer. Dominant mutation
Stem cells
Unspecialized cells
Totipotent. Can become one of 200+ types of cells found in adults
Differentiated cells
Cell becomes specialized
Pluripotent cells
Can become a limited number of cells
Multipotent cells
Can become just couple of cell types
CAMS
1.Cell adhesion molecules
2. Almost on every cell in body
How do cams work?
1.Molecular Velcro that cells use to anchor themselves to other molecules in extra cellular space
2. Act as arms that help cells move against one another
3. Rally wbcs to infected or injured area
4. Transmit info about changes in extracellular matrix to cell. Bring a variety of responses like cell migration, proliferation, specialization
Function of CAMS
Embryonic development and wound repair
(Important where cell mobility is important)
Centrososmes
A region near the nucleus that contains paired organelles called centrioles
Interphase
From the formation of the cell to cell division. has three parts G1, S and G2
Progenitor cell
more specialized than embryonic stem cells but less specialized than fully differentiated cells in body. Give rise to specific types of cells within a particular tissue or organ
Totipotent cells
Can create all types of cells required for body including embryonic tissues
Pluripotent cells
Can make all cells in body except embryonic tissues
RAS
Most frequently mutated genes in human cancer.
family of genes that regulate cell growth and division. mutations can cause cancer
MYC oncogene
MYC Protoncogene protein is a transcription factor. regulates the expression of genes involved in the cell cycle.
