Digestive System part II Chemistry and Cells

Digestive System part IIChemistry and Cells

Atoms• Three major parts.

– Protons: Positive Charge. Inside Nucleus– Neutrons: Neutral Charge. Inside Nucleus: – Electrons: Negative Charge. Outside Nucleus

• 2 electrons in first shell• 8 electrons in the second shell• Eight is Great! Will not React with other

atoms.• If the outer shell is not full it will react.

Combining Chemicals

• Compound: When two or more different elements combine.

• Hydrogen Bond: H2O – When hydrogen bonds with another atom. Creates a polar

molecule.• Covalent bond: CO2

– When atoms on the same side of the chart (same size) bond. Share electrons.

• Both Hydrogen and Covalent bonds form molecules, ionic bonds do not. Ionic/

Covalent Bonds

Periodic Table

Bonding

Combining Chemicals continued

• Ionic Bonds: When atoms on different sides of the chart (different size) bond. Steal electrons. Create Ions. Make teeth and bones.

• Ion: Charged particle either negative or positive. NaCl = table salt– Electrolytes: Ionic compounds that breaak into

cations and anions when dissolved. (Salt)• Free Radical: Electrically charged ion with an

unpaired electron in its outer shell.

Antioxidants, What are they?

• Substances that inactivate oxygen derived free-radicals

• Slows damage from free-radicals• Examples: Selenium, Zinc Beta-carotene,

Vitamins C & E

Acai Berry

Free Radicals

Ph Scale• Measured on grams of Hydrogen (H+)

– pH of 1= 1g of H+, pH of 2= .01g of H+• Acid: form hydronium ions (H+)

– pH of less than 7 ( 1 to 6.9)• Base: form hydroxide ions (OH-)

– pH of more than 7 (7.1 to 14)• Acid + Base: salt & water, the solution is

neutral with a pH of 7. – NaOH + HCL = H2O + NaCl with a pH of 7

What is a Buffer?

• Chemical substances that neutralizes small amounts of an acid or base added to a solution.

• Why are these important to your body?• three main buffers in the body:

– bicarbonate buffer system: in the blood and stomach to neutralize acids

– protein buffer system: inter and extra cellular buffering used with hemoglobin and blood

– phosphate buffer system: used in the urinary system to remove H+ ions and make urine acidic

Metabolism: All chemical reactions necessary to maintain life

• Catabolism - substances broken down, energy released and captured to make ATP

• Anabolism - larger molecules built from smaller ones

• Question: Why are they called anabolic steroids?

Metabolism: What do we eat?

• Carbohydrates (glucose) - broken down to make ATP

• Fats - build cell membranes, myelin sheaths, insulate, ATP

• Proteins - structural materials hoarded by body cells, ATP

Organic Compounds:contain C-H bonds

• Carbohydrate: fast energy–made of Carbon, Hydrogen, and

Oxygen. 1:2:1 proportion. Sacchar = sugar• Monosaccharides:C6H12O6,

glucose and fructose• Disaccharides: 2 sacchar’s: Sucrose,

table sugar• Polysaccharides: Many sacchar’s:

Cellulose (wood) and starch.

Carbohydrates

Dietary Sources of Major Nutrients - Carbohydrates

• From plants except lactose and glycogen in meats

• sugar - fruit, sugar cane, milk• starch - grains, legumes, root vegetables• cellulose - most vegetables

Carbohydrate Metabolism

• Carbs - preferred fuel to produce ATP from glucose (blood sugar): energy from bonds broken binds phosphate to ADP to make ATP

• Fastest energy: simple carbs• Fast but steady energy: complex carbs• Carbon atoms leave as CO2 and hydrogen combines

w/ oxygen to make water

• Question: Why do we breath out CO2?

Carbohydrate Metabolism - Homeostasis of blood glucose

• Hyperglycemia - high levels; excess stored as glycogen and converted to fats

• Hypoglycemia - low levels; liver breaks down stored glycogen and releases glucose to blood

Organic Compounds: C-H bonds• Lipids: long term energy, very few oxygen

atoms–Cholesterol: LDL & HDL

• (HDL is heart healthy)–Saturated fats: All C bonded to H. Lard, and

butter. Don’t eat Transfats (they have been hydrogenated)

–Unsaturated fats: C is double bonded to itself. Oil. Currently considered healthier.

LipidsTrans fats

Lipids

• Neutral fats: saturated in animal products, unsaturated in seeds, nuts, vegetable oils

• Cholesterol - egg yolk, meats, and milk• Phospholipids: the plasma membrane

• PS What organelle in the cell makes lipids?

• Answer: Smooth ER

Lipid Metabolism

• Liver - make ATP, synthesize lipoproteins, clotting protein and cholesterol for membranes or steroid hormones

• Form myelin sheaths and fatty cushions around organs

• Most concentrated form of energy• Liver makes Bile ships it to the Gallbladder. Bile

emulsifies fats. The bilirubin in bile turns feces brown.

Lipid Metabolism

• To be used for ATP synthesis, it must be broken down into acetic acid; when not enough glucose, acetone accumulates in blood making it acidic (acidosis/ketosis)– no carb diets, diabetes, and starvation

– People smell of keytones when they get diabetes, why?

Lipid Metabolism

• Liver - make ATP, synthesize lipoproteins, clotting protein and cholesterol for membranes or steroid hormones

• Form myelin sheaths and fatty cushions around organs

• Most concentrated form of enegy

Organic Compounds:All organic compounds contain Carbon.

• Protein: the working molecule –50 or more Amino Acids make a

protein–Types of Proteins

• Muscle• Enzymes: Control chemical reactions

and can be re-used like a key in a lock• Hair

Protein

Proteins

• Animal products, eggs, milk• Amino acid polymers• legumes, nuts, and cereals are low in one or

more essential amino acids

Protein Metabolism

• Proteins - bulk of cell structures; broken down into amino acids for enzymes, membranes

• Cells use ATP to actively transport amino acids (8 of the 20 are not made by cells - essential amino acids)

General Metabolic Function

• Albumin - most abundant protein; holds fluids in bloodstream– insufficient albumin causes fluid to go from blood to

tissues (edema)– Synthesize amino acids and detoxify ammonia

Protein Metabolism

• Amino acids make ATP when protein is in excess or no fats or carbs– amine groups are removed as ammonia which is toxic so

it combines w/ CO2 to form urea

Central Role of Liver

• Manufactures bile, detoxifies drugs and alcohol, degrades hormones, makes substances vital to body, metabolism– This process uses many enzymes: Speed up

chemical reactions and reduce activation energy.– Most enzymes are Proteins some are RNA

• We have more liver tissue than needed, so if damaged, it regenerates rapidly and easily

General Metabolic Functions

• Liver maintains blood glucose levels• After high carb meal, glucose is removed from

blood and converted to glycogen (glycogenesis) and stored in liver

General Metabolic Functions

• As body cells remove glucose from blood, liver breaks down stored glycogen (glycogenolysis)

• gluconeogenesis - make glucose from fat and protein

Organic Compounds:All organic compounds contain Carbon.

• Nucleic Acids: pg. 37 DNA and RNA–Made of nucleotides: Sugar,

Phosphate, and X• ATP: energy cells run on.

What is a calorie?

• Energy value measured in kilocalories (kcal) or Calories (C

Vitamins: the last of the Organics

• Organic nutrients, small amounts• No one food contains all required vitamins, need

balanced diet• Most function as coenzymes: act w/ enzymes for

Minerals

• Requires adequate supplies of 7: Ca, P, K, S, Na, Cl, and Mg; trace amounts of others

• Fats/sugars have none, cereals and grains poor sources

• In veggies, legumes, milk, meats

Metabolism: All chemical reactions necessary to maintain life

• Catabolism - substances broken down, energy released and captured to make ATP

• Anabolism - larger molecules built from smaller ones

Metabolism

• Carbohydrates (glucose) - broken down to make ATP

• Fats - build cell membranes, myelin sheaths, insulate, ATP

• Proteins - structural materials hoarded by body cells

What are the two forms of cell transport?

• Active Transport: uses energy (ATP) to move molecules against the concentration gradient or to move large things.

• Passive Transport: uses NO energy to move molecules with the concentration gradient.

What types of Passive transport does the body use?

• Diffusion: When molecules move from high to low or with the concentration gradient.– Perfume, food coloring, etc. all do this.

• Osmosis: a specialized form of diffusion which moves water from high to low across the plasma membrane.

What types of Passive transport does the body use?

• Facilitated Diffusion: Uses carrier proteins to move substances without energy with the concentration gradient.

• Filtration: water and solutes are forced through a plasma membrane. Happens in the Kidneys.

What types of Active transport do you use?

• Solute Pumping: Require protein carriers and energy to move sugars, Amino Acids, and ions against the concentration gradient. (Sodium Potassium pump used in Nerve cells)

More Active Transport…

• Bulk Transport: Substances too big to pass through the plasma membrane. – Exocytosis: Large things exit the cells– Endocytosis: Large things enter the cell

• Phagocytosis: Cells that eat- white blood cell• Pinocytosis: Cells drink- intestine and kidneys

• Chromosomes: Tightly wound DNA. Resemble an X because two chromatids are held together.- Supercoiled.

• Centromere holds the chromosomes (Two sister Chromatids) together.

• Chromatid: A single tightly wound strand of DNA.

DNA in all of its fine forms:

Homologous Chromosomes

And last but not least…• DNA is your genetic information. In the

shape of a double helix. The nucleotide pairs are: (Hydrogen bonds)– Adenine= Thymine– Cytosine:. Guanine

• DNA is broken into segments called genes which code for proteins.

• Genes give you your physical characteristics.

Is DNA the final say?

• Epigenetics may play a role.

Epigenetic EffectOn DNA

EpigeneticMovie

Before Eukaryotic Cells Divide…

• Its chromosomes are replicated.• Happens through the process of DNA

Replication. DNA Replication DNA needs enzymes (protein) to copy or replicate itself.• Double helix unwinds using DNA Helicase. • DNA Helicase breaks the hydrogen bonds.• Where the DNA breaks apart is called the

replication fork. DNA polymerase (another enzyme) adds nucleotides at this point.

How many Chromosomes do humans have?

• Each somatic cell or body cell has two copies of 23 chromosomes.

• One copy of the chromosomes (sex cells or gametes) have 23 chromosomes and are called haploid or n = 23.

• Two copies of the chromosomes (somatic cells) have 2n = 46.

There are two types of Chromosomes.

• Autosomal Chromosomes: or autosomes are not sex chromosomes.

• Sex Chromosomes: determine the sex of the individual. The male of the species determines the sex of the offspring. Women only have one X chromosome. Males have an X or a Y.

• XX is a girl• XY is a boy

Karyotypes: Pictures of your DNA. • Why do we take pictures? To find mistakes

The 5 stages of the Cell Cycle 6-2

• G1: Cell Growth and Metabolism• S: DNA is copied• G2: Cell prepares for division.• Mitosis: Nucleus divides, cell parts separate.• Cytokinesis: Cytoplasm divides

When control of the Cell cycle is lost: Cancer is the outcome.

• Cancer: uncontrolled cell division or death.• Read pg 66: Common Disorders

Hit the Cancer BiologyDocumentary Link

Mitosis The Basic Steps:6:3

• Prophase: DNA forms chromosomes. Nuclear envelope disappears. In Animals spindle fibers form.

• Metaphase: Chromosomes move to the center of the cell- pulled by spindle fibers.

• Anaphase: Chromosomes are separated into chromatids. Spindles shorten pulling chromatids to opposite ends of the cell.

• Telophase: Nucleus reforms. Chromatids turn back into Chromatin. Spindles disappear. The Jazzy

Version ofMitosis

After Mitosis: Pg. 131,132

• Cytokinesis: Cytoplasm divides in half. • Animals: The plasma membrane pinches in

half= Furrow.• Plants: A cell wall grows between the two

new cells. Cell Plate.

Cell Cycle Movie/Game

Basal Metabolic Rate• Carbs & proteins yield 4 kcal/g, fats yield 9 kcal/g• Basal metabolic rate (BMR) - amount of heat

produced by body per unit time at rest; energy supply for breathing, heartbeat, and kidney function

Basal Metabolic Rate• Avg. adult has BMR of 60-72 kcal/hr; influenced by

surface area, gender, age, and thyroxin production (more thyroxin produced by thyroid gland, higher O2 consumption and ATP use and metabolic rate)

Basal Metabolic Rate• Hyperthyroidism - excessive rate, lose weight

despite increased hunger and food intake, bones and muscles weaken

• Hypothyroidism - slow rate, obesity, diminished thought process

Total Metabolic Rate

• When active, more glucose must be oxidized to provide more energy for activities

• Total Metabolic Rate (TMR) - total amount of kcal body must consume to fuel all activities

• When total calories = TMR, weight is constant• If eat more, excess calories appear as fat deposits• If active w/o enough food, break down fat

reserves and even tissues to satisfy TMR