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A journey into our body
Transcript of A journey into our body
Here we go!
YUm! this lunch is delicious! I wonder how the food i eat gets broken down and how it is used throughout my body?
i bet Ms.Frizzle knows the answer!
Too bad, she's gone on vacation this winter break. Shes gone to Hawaii, she's probably enjoying the sun!
I should call Liz, Maybe he can lend be the magic school bus, so that i can find the answer!
Hey Liz, Can i borrow the magic school bus for a journey into the body!
You are one of Ms.Frizzle`s best
students! HAve Fun on your trip!
There are 3 processes from the point when food enters the body to when it leaves the body:
i)digestion-breakdown of food into small pieces either physically or chemically
ii)absorption-process of taking molecules into the body
ii) elimination- removal of undigested solid material, excretion
When I ate my sandwich, my mouth mechanically processed it by chewing and also by the digestive enzyme Salivary amylase.
Salivary Amylase is produced by salivary glands and the pH is neutral.
As I swallowed, a bolus was formed by my mouth,teeth,tongue and saliva from the glands.
The esophagus moves the bolus into the stomach by
which is the rhythmic contraction of the esophagus, intestine and stomach. The bolus is pushed in one direction.
Here are some major digestive enzymes located in our body
In the stomach, gastric juices breakdown compounds by the use of water(hydrolysis). They also kill any bacteria on the food. Food becomes semi liquid mass (acid chyme)
Pepsin is produced by the gastric glands which have a pH of 2 (acidic) which breakdown proteins and then produce peptides.
Is approx. 6 m in length and 3 cm in diameter and first 15 cm is the duodenum.
It produces the enzymes: lactose, peptidase,maltase, nulceosidases.
Absorption is the most important function
The structure has highly convoluted walls to increase the surface area. It is also covered with villi (for more SA). The more surface area, more absorption can then happen. Absorption takes place in the columnar cells. Sugar and amino acids are absorbed by capillaries. Glycerol and fatty acids are absorbed by lymph lacteals.
Comes after the small intestine, it includes the colon and rectum.
Colon: reabsorbs water and some salts
Has a large population of E. coli bacteria which digests indigestible material and produces gases, amino acids, and vitamins
Wow! From looking inside the body and seeing what happens, I have learned so much already!
That is how the digestive system works but there are also 3 accessory organs:
i) Pancreas-produces trypsin,pancreatic amylase,and nuclease. Pancreatic juice enters at the duodenum. and the sodium bicarbonate are important since they neutralize stomach acid to make it slightly basic. Also produces hormones like Insulin and Glucagon which regulate blood glucose levels in blood.
ii)Liver-bile is secreted from the gall bladder to the duodenum. It emulsifies fat (breaks fat droplets into tiny droplets). Breakdown fluid of hemoglobin in RBCs. Also, increase surface area of the fat droplets for Lipase to work on.
iii)Gall bladder-plays an important role of storing bile (which is produced in the pancreas) until its needed for digesting fatty foods in the duodenum of the small intestine.
Seeing how the digestive enzymes like pepsin and salivary amylase work really fascinated me, I want to see how enzymes work in more precision and detail and I also want to know what kinds of factors affect them? The digestive system relates to enzymes since it has enzymes helping in the digestive process.
Here we go!
A protein which speeds up a chemical reaction without being used up and reduces activation energy.
They are highly specific, each enzyme speeds up 1 reaction.
enzyme catalyzed reaction:
S=substrate (reactant) which binds to active site
ES=enzyme substrate complex where chem. rxn. occurs
P= new product that is formed
Is a smaller non protein required to make an enzyme active ie. vitamins.
Causes reactions to proceed fast enough for life.
holds reactant molecules together long enough for them to react
stress bond of a substrate assist in breaking apart
controls metabolic pathways.
types of models
I)Lock and Key model- where substrate is shaped like active site and binds perfectly
II) Induced fit model- where substrate and active site do not have the same shape therefore the active site alters it shape and when the product leaves, the active site returns to its original shape.
Factors affecting enzyme activity
i)Inhibitor- a molecule that mimics the substrate and binds on the active site. Also slows the reaction rate.
ii) Non competitive inhibitor- binds to another place on enzyme and not on the active site. Slows rate.
iii) pH- too low pH and high pH kills enzymes (denature). Neutral pH is optimum and the fastest rate
iv)Temperature- low temp causes slow reactions, high temperatures over 40 degrees C causes enzymes to denature, and 37 degrees C is the optimum temp. for human enzymes for the fastest rate possible.
v) Substrate Concentration- more substrates helps KMT and goes faster but at a point it goes at a steady state when active sites are full
vi) Enzyme Concentration- adding more enzymes helps KMT (faster) but if substrates deplete then the product production stays at a steady state
Enzymes are a cell process and application similar to transport proteins in the cell membrane. Most enzymes are proteins therefore transport proteins used in active transport also require enzymatic activity to work.
Lets go see how transport in the cell membrane is run!
Here we go!
transport across the cell membrane
Semi permeable membrane- only small and non charged particles can enter and pass through ie. O2, CO2
Selectively Permeable Membrane- larger,noncharged, charged partciles enter or leave the cell ie Na+, Cl-,aa, glucose(noncharged), hormones.
Like enzymes, proteins in the selectively permeable membrane help make the reaction faster
6 ways membrane selects what moves across the membrane
i) diffusion- particles move from high to low concentration.
ii)osmosis- net movement of water molecules from high to low concentration
iii) facilitated and passive transport- particle movement from high to low concentration with no energy but moved by carrier proteins and also moves towards concentration gradient
iv)active transport- movement from low to high concentration with energy and carrier proteins and against concentration gradient
v)endocytosis-taking in of molecules by forming a vesicle, it uses energy ie. phagocytosis (large particles ) and pinocytosis (small particles)
vi)exocytosis-reverse of endocytosis but also uses energy,dumps content outside
-(high) to (low)
-with concentration gradient
-no energy used
-(low) to (high)
-against concentration gradient
-Na, K pumps
Transport through the membrane is so interesting its just like how I am transporting around in the magic school bus!
Proteins help in the membrane for transportation but now I would like to see how proteins are synthesized. Lets go!
Here we go!
OUR final stop!
RNA-genetic material of some viruses and is necessary for protein synthesis to occur
RNA consists of nucleotides, the 3 subunits are:
a) 5-Carbon Sugar
b) Phosphate group
c) nitrogeneous bases ( A,U,C,G)
RNA has uracil and is single stranded with no double helix
RNA is produced by DNA from
Mrna- takes message from dna to ribose
trNA-transfers aa to ribosomes
rRNA- along with protein, makes up ribosome
codon-3 nucleotides, a triple unit of an mrna molecule
triplet-3 letter, 3 nucleotide unit
-genetic (minor, only nucleotide changed)
-point and frameshift (change in aa-lethal)
crash course video on protein synthesis
The digestive system is related to the central concept of protein since protein is digested into the body producing peptides which then produces amino acids. Digestive enzymes are involved in breaking down the protein for example pepsin in the stomach, and trypsin in the pancreas.
As mentioned earlier, enzymes relate to the central idea of protein since there are different types of enzymes which are specifically made to break down protein into peptides. Also, some enzymes are proteins which help the overall speed of a reaction by making it faster.
Transport Across Cell Membrane
Transport across the cell membrane relates to the idea of protein because in active transport, protein carriers and ATP are required in order for a reaction to work efficiently and effectively. Transport proteins then make transportation across a cell membrane much faster.
RNA & Protein Synthesis
RNA & Protein Synthesis relates to protein because RNA is the genetic material of some viruses and it is necessary in all organisms for protein synthesis to occur. The synthesis starts from DNA to mRNA and eventually to protein because of synthesization through transcription (DNA to mRNA) and translation (mRNA to protein).
That was a spectacular journey through the body! I learned so much about the digestive system, enzymes, transport across the membrane and RNA/protein synthesis. I also learned that all four of these topics are related to one central and common concept, protein.
Thanks for joining me! See you next time!