Biology 20 Biochemistry
Where do chemical reactions occur in the body?
Within water of the cells and tissues
When is a solution neutral?
When hydrogen ions equal hydroxide ions
When is a solution Acidic?
When there are more hyrdrogen ions than hydroxide ions
When is a solution basic?
When the number of hydroxide ions is greater than the number of hydrogen ions
What different levels of acidity are in the human body?
pH 2.5-3.0 -> Stomach acid
pH 8 -> intestines
What happens when the pH of the body is changed and why?
Cellular functions need a specific pH to work, and when this is changed they cannot carry out their necessary tasks
What are OH- and H+ receptors in the body?
They act as "buffers" within the body to regulate pH changes by absorbing excess acid or base
What is the difference between netralization and buffers?
Neutralization is changing an acid or base to neutral
Buffers maintain a specific acid or base level and don't change it
What are the four essential macromolecules?
1)carbohydrates
2)Lipids
3)Proteins
4)nucleic acids
What is the element that makes up the framework of all macromolecules and why?
Carbon, because it has four places to bond with other molecules/atoms
What are organic molecules?
Molecules within the body containing carbon
What are inorganic molecules?
Molecules in the body not containing carbon
What is Anabolism?
the formation of larger molecules from smaller ones
Needs energy to work
What is Catabolism?
The breaking down of larger molecules into smaller ones
Releases energy
What is the medium for metabolism?
Water because of its solvent properties
What is the body's most important source of energy?
Carbohydrates
What are carbohydrates made of?
Oxygen, hydrogen, and carbon
How do humans get carbs?
Cannot make them ourselves, rely on plants
What are the two forms carbs can take?
single sugar units or polymers of many sugar units
What is a monosaccharide?
A single sugar unit containing oxygen, hydrogen, and carbon in a 1:2:1 ratio
What is the difference between an isomer and a polymer
isomer - one single unit of sugar
polymer - multiple conjoined sugar units
What is a Disaccharide?
Double or two conjoined sugar units
how are polymers (disaccharides and polysaccharides) formed
Through a condensation reaction which takes water out of the molecules to allow them to join
What are examples of Disaccharides?
maltose, sucrose, lactose
What are polysaccharides?
polmers made from condensation of 3 or more sugar units
starch is an example
What is starch?
present in plant cells
long chains of carbs
comes in two forms - amylose and amylopectin
starch is stored in seeds and used as energy until plant can photosynthesize
What is glycogen?
what is the difference between starch and glycogen?
glycogen contains more chains of glucose
What is hydrolysis?
breakdown of Polysaccharides to Monosaccharides - takes in one water molecule
What is cellulose?
storage molecule for plants
made up of chains of glucose attached by hydrogen bonds
these bonds make the plant's cell wall stiff and tirgid
this is a structural molecule
cannot be broken down by mammals
Why are starch and glycogen good energy molecules
Can easily undergo condensation or hydrolysis to store or use as energy
Why are polysaccharides always storage molecules?
Because of their larger size they are relatively insoluble
starch and glycogen are examples of this
they hold many bonds that 'store' energy until it is needed
How do you calculate the number of hydrogen bonds in a polysaccharide?
Number of monomers = n
Number of bonds = (n-1)
Cellulose (2)
Source: Plant
Subunit: B-glucose
Bonds: 1-4
hydrogens are opposite and staggered in chain
shape is linear and parallel
Starch (2)
Amylose
Source: plant
Subunit: a-glucose
bonds: 1-4
No branches
hydrogens are on same side as one another, no gaps
shape is helical
Amylopectin
Source: Plant
Subunit: a-glucose
bonds: 1-4 and 1-6
Branching (about every 20 subunits)
Shape is branching but not super compact
Glycogen (2)
Source: Animal
Subunit: a-glucose
Bonds: 1-4 and 1-6
Branching (about every 10 subunits)
Shape is branched and very compact
Function of Alpha glucose?
- used to build starch and glycogen
- energy molecule
Function of beta glucose?
- Used to build cellulose
- energy molecule
Function of D-Ribose?
- component of genetic material RNA (ribonucleic acid)
Function of Deoxyribose?
- component of DNA (deoxyribonucleic acid)
Function of Maltose?
- intermediate in the digestion of starch
- used as sweetener and found naturally in peaches and pears
Function of Sucrose?
- source of energy
- used as the most common sweetener
Function of Lactose?
- energy providing nutrient
- "milk sugar" produced by lactating mammals
Function of starch (amylose)?
- storage
- more difficult for humans to digest compared to amylopectin
- low glycemic index - slow rise is blood sugar
Function of starch (amylopectin)?
- storage
- easier for humans to digest compared to amylose
- high glycemic index (fast rise in blood sugar)
Function of glycogen?
- storage in muscles and livers of mammals
Function of Cellulose?
- Structure inplant cell wall
What are the characteristics of a Lipid?
- non-polar
- insoluble inpolar solvents
- hold more energy per unit than both carbs and proteins (9Kcal/g)
- Composed of two structural units (glycerol and fatty acid)
What is a phospholipid?
- hydrophobic tail (fatty acids) and hydrophilic head (phosphate and glycerol)
Why do phospholipids make up the most of a cell membrane?
They keep the inside of the membrane dry due to their bilayer configuration keeping the heads submerged in water and the tails dry and compacted next to one another
What are the polar differences between the head and tail of the phospholipids?
head - polar
tail - non-polar
What are the three types of lipids?
- tryglycerides
- phospholipids
- steroids and waxes
What are the two types of fatty acids?
Saturated and unsaturated
Characteristics of saturated fatty acids
- solid at room temp
- single bond between carbons (no double or triple bond and no bend in molecule)
- denser and more harmful formations than unsaturated fats
Characteristics of Unsaturated fatty acids
- liquid at room temperature
- more doble bonds -> lower melting point
- the double bonds of the carbons allow molecule to bend and form less dense formations
What are the two types of unsaturated fats?
Cis -> hydrogens attached to double bond are on same side -> more bends in molecule
Trans -> hydrogens are on opposite sides -> creates unatural linear shape that is the most unhealthy for you
How are trans fatty acids made?
industrial process of hydrogenation -> adding hydrogens for longer shelf life
What state are cis vs. trans fatty acids in?
cis -> liquid
trans -> solid
What are the characteristics of triglycerides?
- most common and largest class of lipids
- stored in animals as solids
- stored in plants as liquids
- formed when condensation reaction occures between three fatty acids and one glycerol molecule
What are the functions of triglycerides?
- long-term energy storage
- thermal insulators to body temperature in our habitat
Functions of lipids (5)
1) phospholipids make up cell membrane and some lipids act as hormones
2) lipids have twice the energy content of carbs and proteins
3) heat insulation in animals
4) storage molecule - doesn't require water
5) for protection of exposed internal organs
What are some characteristics of proteins?
- structural components of all cells
- composed of hydrogen, carbon, oxygen, AND nitrogen (sometimes sulphur)
- made up of amino acids
- has a central carbon atom
What are the components of an amino acid?
- carboxyl group
- amino group
- hydrogen atom
- R group - specific to 20 different amino acids
What determines if an amino acid is polar or non-polar?
- depends on the side chains of the amino acids
- non-polar -> non-polar side chains (R groups)
- polar amino -> polar side chain (R group)
Number values of amino acids
20 total
12 of them created naturally
8 of them through diet (essential amino acids)
Characteristics of Nonpolar side chains
- hydrophobic
- no overall charge or unequal distribution of electrons on R group
- only change is the R group, which gives different chemical properties
- there is no oxygen in nonpolar side chains
Characteristics of Polar side chains
- hydrophilic
- partial or unequal distribution of electrons in R group
- contains oxygen and sulfur
Characteristics of Electrically charged side chains
- hydrophilic
- polar
full gain or loss of electrons resulting in complete charge
- contains NH+ if positive
- contains O- if negatively charged
Steps to identifying properties of an amino acid?
1. is it an amino acid? Do you see an amine group, a carboxyl group, and an alpha carbon?
2. Find the R group, do you see an oxygen atom?
a. NO.. amino acid is non-polar
b. YES.. do you see a charge?
i. NO.. amino acid is polar
ii. YES..amino acid is an ion
What is a peptide bond?
Amino group of one AA links with the Carboxyl group of another, they undergo a condensation reaction and a water molecule is removed, linking them together
What is it called when multiple peptide bonds are linked together?
Polymerization
What is a polypeptide?
3 or more amino acids
What is a protein made up of?
one or more polypeptides
The functions of a protein?
1. transport
2. contraction of muscles
3. enzymes
4. hormones
5. antibodies
6. structural proteins
7. storage
8. plasma proteins
9. receptors
what is entropy?
measure of the unusable energy within a system
what are energy systems?
involve energy input, energy conversions, and energy output
where do energy conversions occur?
Within cells.
what are metabolic reactions?
are reactions that occur within the cells of plants and animals
what is activation energy?
energy required to initiate a chemical reaction
what are reactions that release energy called?
Exergonic
What are reactions that need a constant stream of energy?
Endergonic
what are metabolic pathways?
a series of steps from a starter molecule or precursor toward a final end product
How do enzymes contribute to metabolic reactions?
1) speed up reactions in the form of biological catalysts
2) control metabolism within all organisms
3) lower the amount of activation energy necessary for a metabolic reaction, therefore less energy is needed for the goal to be reached
What are catalysts?
chemicals which regulate the rate of chemical reactions without themselves being altered
What are the energy requirements for all reactions?
1) reactants need to have bonds broken
2) molecules need to re-orient
3) new bonds need to be formed
What will enzymes do in a catabolic reaction?
Will break apart a substrate into two or more pieces
What will enzymes do during a anabolic reactions?
They will join two or more substrates together into one product
How do substrates and enzymes join?
Substrates can only fit into very specific enzymes, but because they are both in abundance within the body random collisons ensure that they will join together
What is an enzyme-substrate complex?
When the two components are bonded together
What determines the shape of an enzyme and the type of substrate it can take on?
The folding of its amino acids within the protein
What are the components of an enzyme?
Pocket/Active site
Enzyme body
Allosteric inhibitor site
What are the two different theories surrounding substrate-enzyme complexes?
Lock and Key model
Induced fit model
Describe the induced fit model
When the active site of the enzyme shifts in shape slightly to accomodate the substrates entering it and changing them during the reaction. The substrates will be changed after this, but the enzyme will return to its original shape and can be used again.
What are the factors that affect enzymes?
- temperature
- pH
- enzyme concentration
- substrate concentration
What will happen to an enzyme if its not in the proper conditions
It will denature, meaning that its folds will loosen and the active site will no longer fit the correct substrate
Describe temperature in relation to enzymes
- reaction rate increases as temperature increases
- this is because temperature increases the number of collisons
- temperature cannot be too high or low or it will denature (too low and no movement, too high and too much movement as well as denaturation)
What is the optimal human body temperature?
about 37 degrees celcius
Describe pH in relation to enzymes
- different parts of the body function at different pH's, and therefore the enzymes within those parts will have different optimums
- a pH too low or high will denature an enzyme
Describe how concentration of substrate molecules can affect enzymes?
- the greater the number of substrate molecules the greater the number of collisons and substrate-enzyme complexes formed
- this will increase until the number of enzymes becomes a limiting factor
(this is the same for enzyme concentration)
What is allosteric regulation of enzymes?
changing of an enzymes capabilities or activity due to an outsider molecule called an effector
this binds to a part of the enzyme other than the active site
this is reversible
What is the difference between positive and negative allosterism?
positive:
- improves binding affinity
- example is oxygen in haemoglobin
negative:
- reduces binding affinity
- can also be called non-competitive inhibition as it is reducing binding capabilities but not in direct competition with substrates for the active site
What are the three factors which contribute to how well an enzyme can moderate metabolism
1) the rate of enzyme production and breakdown
- this has to be somewhat balanced in order for the continued functionality of metabolic reactions
2) enzyme interactions with substrates
- have to be constant and numerous
3) presence of inhibitors
- will seriously inhibit or stop ability to bind with substrates
What are competitive inhibitors?
when substances other than the substrate bind directly with the active site in order for the substrate to not gain access
An example of this is carbon monoxide taking the place of oxygen in an enzyme due to the fact they have the same compound shape and therefore the enzyme cannot tell the difference
What are statins?
competitive inhibitors purposely used to lower cholesterol, as it blocks the active site of the enzyme
What are non-competitive inhibitors?
An inhibitor affects the enzyme by binding to a site other than the active site and reducing its ability to bind with a substrate
Unlike competitive types, this cannot be solved by increasing the amount of substrate available to move the inhibitor
What is end-product inhibition?
The use of an allosteric inhibitor (non-competitive) as a way to turn an enzyme "on" and "off" when necessary
In this way, the inhibitor can be the final product and can stop the enzyme from completing earlier steps in the metabolic pathway that are no longer necessary
What is end product inhibition a form of?
Negative feedback
What is irreversible enzyme inhibiton?
- mechanism based inhibition
- when an allosteric inhibitor irreversibly binds to an enzyme, making sure no other substrate can reach it and harming the organism
What is the krebs cycle an example of?
intracellular enzyme-catalyzed reactions
What is digestion a form of?
extracellular enzyme-cactlyzed reactions
What are the five processes of the digestion system?
- ingestion -> taking in of necessary nutrients
- digestion -> the breakdown of complex molecules into smaller pieces with more surface area
- absorption -> the nutrients into the blood
- assimilation -> nutrient transport to the cells of the body
- egestion -> matter leaves digestive tract (not excretion)
What is the difference between physical and chemical digestion?
physical - the actual physical breakdown without any molecule changes
done so more surface area is created to act on, as well as fit through the digestive tract
The parts responsible for this: teeth, tongue, muscle movements
chemical - macromolecules are broken down chemically by enzymes
chemically breaks bonds on molecular level
What are the components of the walls of the intestinal tract?
Lumen
Villi
Mucosa
Sub-mucosa
Longitudinal muscle
Circular muscle
(amount of villi depends on whether the specific part must do a lot of absorption or not)
What is the difference between endocrine and exocrine glands?
endocrine:
- secretes hormones directly into the blood, closed system
exocrine:
- secretes hormones or enzymes into a duct, eventually releasd from body
What is the first stage of digestion?
1) digestion in the mouth
Physical digestion in the mouth
- teeth and tongue
- increases surface area for enxymes to work
- food is mixed with saliva produced by the submaxilliary and sublingual glands
chemical digestion within the mouth
- salivary amylase within the saliva starts to break down carbohydrates
this is initiated by a nerve reflex when the mouth tastes or smells food
What are the contents of salive?
- water
- mucous
- salts (to balance pH)
- salivary amylase
What is the function of saliva?
-lubrication
-dissolves food particles
-cleans mouth of debris
-begins digestion of carbohydrates
What is peristalsis?
It is the movement of the longitudinal and circular muscles of the esophagus after the swallowing of food through the larnyx that allows for the food to continuously move downwards without the risk of it coming back up
What is the 2nd stage of digestion?
Digestion in the stomach
- is a j shaped organ below the ribs
- bag shaped and filled with liquid, so ended with sphincters
cardiac sphincter
- stops gastric juice from entering the esophagus
- allows new food to enter the stomach
pyloric sphincter
- stops acidic chyme from entering the small intestine
- allows small amounts of food to pass through
How are gastric secretions controlled?
made up of:
-mucous
- acid
-enzymes
controlled by the enzyme GASTRIN which circulates the blood and prolongs the production of gastric juices
What are the cells within the wall of the stomach, and what do they secrete?
mucous cells - secrete muscous as a protective coating for the stomach wall
parietal cells - secrete HCL to lower pH of stomach to allow enzymes to work, but also helps physical and chemical digestion and the killing of harmful microbes
chief/peptic cells - secrete pepsinogen, which then turns into the active enzyme pepsin in contact with HCL to start the digestion of protein
What are ulcers, how are they caused, and how are they treated?
Ulcers are when damage is caused to the lining of the stomch, causing the stomach wall to be vulnerable to harmful enzymes and bacteria.
One cause of stomach ulcers are the bacteria H. Pylori, which is a bacteria which secretes muconase, an enzyme which breaks down mucous and therefore leaves the stomach lining vulnerable to attack. - this happens over many years as most (50-70 percent) of adults have this type of bacteria.
- two types of treatments - antibiotics and medications (competitive inhibtors) to slow down HCl production
What is the primary function of the stomach?
to begin digestion
to absorb alcohol, water, and monosaccharides already present in food (straight sugar)
What are the three parts of the intestine, how big are they, and what are their roles?
- duodenum - first 25-30 cm and is the source of major digestion
- jejunum -next 20-30 cm and is a transitional area for nutrients
- Ileum - remaining 6 m and is the major absorption area
How do liver secretions enter the small intestine?
- common bile duct from liver
- cystic duct from gallbladder
How do pancreatic secretions enter the small intestine?
pancreatic duct
What are the three major secretions into the small intestine?
Liver secretions (bile), pancreatic secretions, and intestinal secretions
What does the liver produce and where is it stored
Bile stored in the gall bladder
What hormone controls bile?
Cholecystokinin or cck
What hormone is secreted from the stomach wall in the presence of highly fat foods?
Enterogastrone
What are the three components of bile?
Bile pigments, sodium bicarbonate, bile salts
What is the function of bile pigments
- broken down haemoglobin or dead red blood cells that need to be excreted through feces
What is the function of sodium bicardonate from bile
- neutraizes stomach acid to reach the proper ph for the duodenum which is around 8
What is the purpose of bile salts?
- emulsify fats and turn them into tiny droplets to increase surface areas for lipases
What hormone controls pancreatic secretions?
- secretin
- passes through the bloodstream to the pancreas
What are the major components of pancreatic secretions?
- sodium bicarbonate
- pancreatic amylase
- pancreatic lipase
- trypsinogen
- nucleases
What does pancreatic amylase do?
- turns long chain polysaccharides into short chain polysaccharides
What does pancreatic lipase do?
- turns lipids into fatty acids and glycerol
What is trypsinogen?
- the inactive form of trypsin, which is activated by enterokinase
- continues the digestion of protein
- long polypeptides - short polypeptides
What are nucleases?
- turn nucleic acids into nucleotides
How are intestinal secretions released?
- stimulated in the presence of food in the small intestine
- many are immobilized/inactive enzymes that need food to work
What are the components of intestinal secretions?
- mucous
- sodium bicarbonate
- enterokinase
- erepsins
- intestinal carbohydrases
What does mucous do in the duodenum?
- lubricates and protects intestinal lining from proteases
What does enterokinase do in the duodenum?
- acts on trypsinogen to produce trypsin
What are the two types of erepsins and what do they do?
- they turn short chain polypeptides into amino acids through targeting different ends of the polypeptide chains
- aminopeptidases attack the amino side
- carboxydases attack the carboxyl side
What are the three types of intestinal carbohydrases?
- maltase
- sucrase
- lactase
What has happened to all nutrients after digestion (but not absorption) is complete?
- carbohydrates have been converted into soluble monosaccharides
- Proteins have been converted to amino acids
- lipids are either emulsified droplets or glycerol and fatty acids
- vitamins and nutrients have been released from the food
How are digested nutrients absorbed into the bloodstream?
- through the Ileum
- all except for water, alcohol, and some monosaccharides
How is the Ileum adpated for its job?
- long and folded internally
- thin, moist lining
rich blood supply
- surface area covered by villi and microvilli
- each villi has a capillary network and a lacteal
Microvilli?
- ruffling of epithelial membrane which further increases surface are
How does rich blood supply help the Ileum?
- dense capillary network helps absorb nutrients right into the bloodstream
What is the single layer epithelium?
- minimizes diffusion distance between blood and nutrients
Lacteals
-absorb lipids from ileum to lymphatic system
intestinal glands
- exocrine pits, release digestive juices
membrane proteins
- facilitates movement of nutrients into blood stream
What is the mnemonic for intestinal adaptations
MR SLIM
How are glucose and amino absorbed into the bloodstream?
- absorbed into blood capillaries through either simple diffusion or facilitaed diffusion
- facilitated if hydrophilic
- simlpe if hydrophobic
How are fatty acids and glycerol absorbed?
- into lacteals via simple diffusion
How are lipoproteins and fat droplets absorbed?
- endocytosis/pinocytosis through the lacteal
How are minerals and vitamins absorbed?
- active transport
What is the role of the liver?
- regulates blood glucose levels
- synthesizes plasma proteins
- blood components
- detoxifies blood
- demaminates amino acids into urea (removes NH4 by removing N) (urea is then drained through kidneys)
- converts haemoglibon into bile pgments by emusifying fat
- breaks down alcohol, drugs, etc
- prodices cholesterol
- stored vitamins and minerals
What is the function of the large intestine?
- indigestible food, cellulose, dead cells, bile pigments, and water pass through
- this is a thin liquid called chyle
- main secretion is mucous
- has lots of gut flora which is a symbiotic relationship
- water is reabsorbed and what is left is excreted out as feces
What is the nasal cavity?
air filled space behind nose and in the skull, warms and humidifies air
nostrils
antryway for nasal cavity, lined with hair and mucous
pharynx
opening in upper back of throat, behind the uvula
epiglottis
flap that prevents anything but air from entering trachea
larynx
voice box, air passes through to create sound, located in the trachea
cartilage
strong flexible tissue, structural support
trachea
windpipe, passage for air, warms air, lined with cillia to avoid debris
bronchus
passage for air into lungs
lung
contains part of the bronchi, bronchioles, and alveoli, function to permit gas exchange
bronchioles
further branches of bronchi
pleural cavity
fluid filled space around the lungs, without which would tear
thoracic cavity
- contains respiratory and heart
diaphragm
band of muscles that separate thoracic cavity and predicts the movement of air through relaxation and contraction
Alveoli
air spaces where gas exchange happens
Capillary network
small blood vessels which surround each aveoli
oxegenated blood vs deoxygenated blood
blood that carries a high concentration of oxygen vs blood that carries a low concentration of oxygen (relative to the amount of coarbon dioxide)
What makes lungs more effective?
when they are permeable, thin, moist, and have a large surface area
What are the features of the lungs that allow for efficient gas exchange?
- single layer of flattened cells for small diffusion area
- dense capillary network tht maintian a concentration gradient
- high volume of spherical aveoli clumped together to maximize surface area
- cells in lining secrete fluid called surfactant for lubrication, allowing gases to dissolve from gas to liquid, and to prevent tearing/ripping
- branched network of bronchi allowing for more alveoli
What are type 1 pneumocytes
thin epithelial cells within the alveoli that exchange gases efficiently through their flattened shape and therefore increased surface area
What are type 2 pneumocytes
Granular, cube shaped epithelial cells within the alveoli that produce surfactant to prevent tearing
Describe surfactant
prevents the moist layer surrounding alveoli from increasing in surface tension and causing tearing and collapsing -it does this through moving with the alveoli when it is expanding- this also causes different sizes to inflate at roughly the same rate, easier for oxygen to diffuse through dissolution,
Why do bigger animals need a bigger respiratory system?
Because as an organism gets bigger, the volume between its outer cells and system gets bigger, and therefore more surface area is necessary to supply enough oxygen
What causes inhalation and exhalation
pressure differences within and outside the system
- in - pressure in chest is less than outside
- out - pressure in chest is greater than outside
diaphragm regulates this
What muscles control inhalation and exhalation?
are antagonistic - internal and extrenal intercostals - and dictate how the diaphragm moves
in - eternal intercostals flatten diaphragm and increase the volume of the thoracic cavity
They pull the ribs up and outwards and contract the diaphragm
out - internal intercostals dome the diaphragm and decrease the volume of the thoracic cavity
They pull the ribs down and in
What dictates changes in ventilation, and how?
excersize and physical acitivty
more ATP is needed, produces more CO2, CO2 receptors sense this, demand for gas exchange increases
this will increase the frequency of breaths (ventilation rate) and tidal volume or depth of breaths
How is ventilation measured
observation
chest belt and pressure meter
spirometer
Different types of breathing rates
tidal volume - normal
ERV - breath in normally and out as much as possible
IRV - how much breath can be inhaled - is only calculable
Vital Capacity - biggest inhale and exhale possible
how is breathing regulated?
sensors in the brain and ph changes
central chemoreceptors?
sensitive to acidity in blood, which is directly linked to the concentration of CO2 in blood, (due to reaction of CO2 and H20), repiratory will then stimulate intercostals and diaphragm to increase breathing rate and capacty (to expel CO2)
Peripheral chemoreceptors?
in the walls of cartoid and aortic arteries and are sensitive to changes in blood ph, also regulate O2 levels in blood and change breathing rates accordingly - too low and they increase breathing rate, but this is secondary to CO2 receptors
How do high altitudes affect breathing rate?
oxygen decreases as altitude increase, which is why the O2 receptors are important, and as such the depth of breath will increase (people living in high altitudes will have greater tidal volumes)
Carbon monoxide poisoning
reduces oxygen levels through direct competition, can be solved through interacting with more oxygen
How is oxygen transported across the epithelial membrane to the blood?
The haemoglobin has four bonding spots for oxygen on each side, this creates a gradient where the oxygen bonds increasingly fast until it slows down when there are no spaces left to bond, the same thing happens when carbon dioxide leaves into the aveoli
What are the three types of muscle
cardiac
smooth
skeletal