Autotrophic species – self feeders, photosynthetic organisms or producers.

Organisms are differentiated into two types:

1. Chlorophyll bearing – with green pigment.

2. Non chlorophyll bearing – absence of chlorophyll.

Autotrophs Plants Some Protists Some Bacteria Nearly all Archaea

• Heterotrophs– Animals– Fungi– Most Protists– Most Bacteria

• Heterotroph1. Saprophytes – mushrooms, bread molds and

decay bacteria.

2. Parasites – depend on other organisms for survival.

Why do we see green? Green color from white

light reflected NOT absorbed

Chloroplast: organelle responsible for photosynthesis

Chlorophyll: located within Chloroplast

Green pigment

Photosynthesis – physico-chemical process by which plants use the energy from sunlight to produce sugar which cellular respiration converts into ATP.

In plants and simple animals, waste products are removed by diffusion. Plants, for example, excrete O2, a product of photosynthesis.

2 Phases Light reaction Dark reaction

Light reaction: converts light energy into chemical energy; produces ATP molecules to be used to fuel light-independent reaction

Dark reaction: uses ATP produced to make simple sugars.

LIGHT Reaction Requires light Occurs in chloroplast (in thylakoids) Chlorophyll (thylakoid) traps energy from

light Light excites electron (e-)

Kicks e- out of chlorophyll to an electron transport chain

Electron transport chain: series of proteins in thylakoid membrane

Bucket brigade

LIGHT Reaction Energy lost along electron transport chain Lost energy used to recharge ATP from ADP

NADPH produced from e- transport chain Stores energy until transfer to stroma Plays important role in light-independent

reaction

Total byproducts: ATP, NADP, O2

LIGHT Reaction2 types:1. Photolysis/Hill reaction – compound is

broken down by light.2. Photophosphorylation – creating ATP

by using a Proton gradient created by the Energy gathered by sunlight.

Dark Reaction Does not require light Calvin Cycle

Occurs in stroma of chloroplast Requires CO2

Uses ATP and NADPH as fuel to run Makes glucose sugar from CO2 and Hydrogen

Soil is composed of minerals, organic matter, water, air, and organisms

Soil is full of microorganisms that break down and recycle organic debris

Most roots of plants are found within the topsoil Topsoil – a mixture of minerals, living

organisms and humus (partly decayed organic matter)

Only minerals that are dissolved in water are available for uptake by roots

Approximately one half of the soil volume is occupied by spaces known as pores, which may be filled with air or water

Water held in small pores is readily available to plants

Plants require 9 macronutrients and 7 micronutrients Macronutrients – used by plant in large

quantities Micronutrients – used by plant in trace

amounts Carbon, oxygen, hydrogen, nitrogen

(essential for amino acids), potassium, calcium, magnesium (the center of the chlorophyll molecule), phosphorus, and sulfur

Carnivorous plants have modified leaves adapted for luring and trapping prey

Prey is digested with enzymes secreted from specialized glands

Pitcher plants (common in northeast bogs) – have pitcher-shaped leaves with cavity filled with digestive fluid

Venus flytrap – (grows in bogs in North and South Carolina) – has 3 sensitive hairs on each side of leaf that, when touched, trigger the two halves of the leaf to snap together Once the prey is enfolded within a leaf,

secreted enzymes from leaf surfaces digest the prey

Sundews – secrete sticky mucilage, which traps small animals, and digestive enzymes

Epiphytes – an organism that grows upon, or attaches to a living plant

Most commonly refers to higher plants, but can also include bacteria, fungi, lichens, mosses, and ferns

“Air plants” – do not root in the soil Obtain moisture from the air or from

dampness (rain and cloud moisture) on the surface of their hosts

http://www.flickr.com/photos/pierre_pouliquin/74397619/

The human digestive system is a marvel of nutritional storage and acquisition!

Process of nutrition1.Ingestion – process of taking food into the body.2.Digestion – process of converting complex food into simple forms.Mechanical and Chemical Digestion3. Absorption – nutrients are taken into the cells.

4. Assimilation – utilizing nutrients for various functions.5. Egestion – process of excreting unusable or undigested material from cell or digestive tract.

Animals are classified on how they obtain food:Herbivores are animals that eat plants exclusivelyCarnivores are animals that eat other animalsOmnivores are animals that eat both plants and other animals

Animals are classified on how they obtain food:Scavengers are animals that eat dead animals.Insectivores are animals that feed on insects.

Types of digestion1.Intracellular 2.Extracellular

- Series of tubelike organs that convert food into energy and convert waste into excretable materials.

Ingested food may be stored or first subjected to physical fragmentation

Chemical digestion occurs next, which breaks the food down into subunit molecules

Food particles then pass through the gut’s epithelial lining into the blood (absorption)

Wastes are excreted from the anus

Digestive Tract – tubular passage of mucous membrane and muscle extending about 8.3 meters from mouth to anus.

Mouth, pharynx, esophagus, stomach, small and large intestines and anus.

MouthAccessory Organs1. Teeth – hard bonelike

structures in the jaws.1.1 Temporary teeth –

primary teeth (20)1.2 Permanent teeth –

(32) after the age of 6.

MouthIncisors – front four teeth. Canines – longest and

most stable teeth.Premolars – transitional

teeth between canine and molar.

Molar – large and flat surface.

Tongue – fleshy, movable, muscular organ attached to the floor of the mouth.

Papillae – raised protrusions where majority of the taste buds are located.

4 types of papillae:1.Fungiform – slightly mushroom shaped located at the apex.2.Filiform – thin, long V-shaped cones without taste buds.3.Foliate – ridges and grooves at posterior part of tongue.4.Circumvallate – 3-14 in number present at the back of the oral part of the tongue.

Pharynx – passageway for air and food.3 parts:1.Nasopharynx – nasal cavities 2.Oropharynx – palatine tonsils3.Laryngopharynx – esophagus

EsophagusStraight muscular tube connecting the oral cavity to the stomach.4 basic layers:1.Mucosa – mucous2.Submucosa – mucous secreting gland (papillae)3.Muscularis – upper part4.Adventitia – outermost layer.

StomachMuscular J – shaped organ that lies between esophagus and small intestine.Sphincter – located between esophagus and stomach.Pyloric valve – between stomach and small intestine.

Secretes:Gastric juices and

gastrin (hormone)3 general areas:1. Fundus – upper

portion2. Body – middle3. Antrum – pyloric

sphincter.

Small IntestineLongest portion (22-25ft)Digestion and nutrient absorption is completed.

3 parts:1. Duodenum –

receives partly digested food, bile and other enzymes.

2. Jejunum – mid section

3. Ileum – final portion

Large IntestineExpanded tube which serves as temporary storage of waste product.

Accessory digestive organs Liver – largest organ in body; produces bile

which emulsifies fat Gallbladder – stores and concentrates the

bile Pancreas – produces pancreatic juice which

contains digestive enzymes Bile and pancreatic juice are secreted into

the small intestine

Liver – chemically modifies substances absorbed from the digestive tract before they reach the rest of the body Removes toxins and carcinogens,

converting them to less toxic forms Regulates levels of steroid hormones

(makes them more water soluble) Produces most proteins found in blood

plasma

Digestive Glands – produce secretion needed for conversion of complex food to simple substance.

A. Salivary Glands – produces SalivaSaliva – contains 99% of waterMucin – present in saliva which helps in

lubrication.Salivary Amylase (ptyalin) digests starch

into simple substance.

3 major glands that secrete saliva:1. Parotid – between the ear and back of

lower jaw.2. Submaxillary – lower side of the jaw.3. Sublingual – floor of the mouth near the

chin.

Liver – largest gland on the upper ride of abdomen.

Secretes: Bile juice and bile salts – helps in neutralization

Bilirubin and Biliverdin – greenish yellow pigment in bile juice.

Bile juice – removes wastes from blood stream.

Bile salts – emulsification of fats

Functions of Liver:Digestion of fatsConverts glucose to glycogen in controlling blood sugarDeamination of amino acidsStorehouse of fats, glucose, vit. A,D,E,K, iron and copperStores water

Functions of Liver:Produces RBCs in embryoDestroys old RBC in adultsProduces heparin (clotting factor)Metabolizes toxic chemicalsProduces 80% cholesterol of human body.

Pancreas- Long, yellowish, irregularly shaped gland

beneath the stomach and connected to small intestines.

- Secretes digestive enzymes and hormones.- Neutralizes chyme and break down

proteins, fats and starch.- Secretes insulin and glucagon in blood

stream.

Gastric glands – branched, tubular glands in the mucosa of the fundus and body of stomach.Secretes:HClZymogen (produces pepsin)Mucous cells(mucus)

Intestinal glands – simple tubular glands located in the mucous membrane of the intestine.Secretes: SucraseMaltaseEndo and exopeptidasesSecretory cells

In general, carnivores have shorter intestines for their size than herbivores

Herbivores ingest a large amount of plant cellulose, which resists digestion; these animals have a long, convoluted small intestine

In the mouth, food is physically broken down by teeth (mastication) Similar in function to the gizzard of birds

and worms Salivary glands excrete saliva

Antibacterial agents, mucin production Breaks down starch into glucose Controlled by the nervous system;

tasting, smelling, or even thinking about food stimulates salivation

Vertebrate teeth are adapted to their food source

Carnivorous teeth are pointed that lack flat grinding surfaces

Herbivores have large, flat teeth suited for grinding cellulose cell walls of plant tissues

Humans (omnivores) have carnivore-like teeth in the front and herbivore-like teeth in the back

Swallowing is initiated by voluntary action, but is continued under involuntary control

When food is ready to be swallowed, the tongue moves it to the back of the mouth

In mammals, the soft palate elevates, pushing against the back of the wall of the pharynx

Elevation of the soft palate seals off the nasal cavity

Pressure against the pharynx triggers the swallowing reflex

Bolus (food)

The uvula is the projection from the posterior edge of the middle of the soft palate

Not to be confused with the epiglottis

Plays a key role in the articulation of sound

Initiates the gag reflex Can contribute to

snoring

The esophagus actively moves a processed lump of food (bolus) through muscular action

Swallowing stimulates successive, uni-directional waves of contraction that move food along the esophagus into the stomach peristalsis

The stomach is a sac-like portion of tract Has convoluted surface, allowing

expansion Stores food (functions as crop of other

animals) Contains an extra layer of smooth

muscles for churning food and mixing it with gastric juice – an acidic secretion of the tubular gastric glands of the mucosa

Parietal cells of stomach secrete hydochloric acid (HCl)

Chief cells secrete pepsinogen (inactive), which becomes pepsin (active) at low pH (~2)

2 liters of HCl and other secretions is produced by human stomach every day!

The low pH of the stomach helps denature proteins

Acidity of stomach also kills most bacteria ingested with food

Overproduction of gastric acid can lead to ulcers, a hole through the wall of the stomach

The mixture of partially-digested food and gastric juice is called chyme; chyme leaves the stomach and enters the small intestine

Site of terminal digestion of carbohydrates, lipids, and proteins

Site of absorption of products of digestion (amino acids, glucose, fatty acids, etc)

Efficient digestion takes time, and so only small amounts of chyme may be introduced into the small intestine at any one time

Longest part of the digestive tract Up to 6 meters in humans

Consists of duodenum, jejunum, and ileum Duodenum – first 25 cm; site of most digestion,

receives enzymes from the pancreas and bile from the liver and gallbladder

Jejunum and ileum – site of absorption

• Very large surface area (3200 ft2) – folds, villi and microvilli– Similar to function of mycorrhizae

From liver

Gallbladder

Pancreaticduct

PancreasCommonbile duct

Duodenum

cell

cell

Pancreatic islet(of Langerhans)

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The large intestine concentrates and stores wastes

Much shorter than the small intestine, but larger diameter

Small intestine empties directly into the large intestine at a junction where 2 vestigal structures remain The cecum and appendix

No digestion occurs Absorption of water, remaining

electrolytes and vitamin K (products of bacterial metabolism)

Many bacteria live and reproduce within the large intestine; excess bacteria are incorporated into the feces

Feces are moved along by peristalsis and exit the body through the anus

Animals lack the enzymes necessary to digest cellulose, the structural component of the primary cell wall of green plants

However, the digestive tracts of some animals contain bacteria and protists that convert the otherwise undigestable cellulose into substances that the host can absorb

The activities of the gastrointestinal tract are coordinated by the nervous system and the endocrine system

The nervous system stimulates salivary and gastric secretions in response to sight, smell, and consumption of food

When food arrives in the stomach, proteins in the food stimulate the secretion of gastrin, which triggers the release of HCl and pepsinogen from the gastric glands

After a carbohydrate-rich meal, the liver and skeletal muscles remove excess glucose from the blood and store it as glycogen

During fasting or exercise (low levels of glucose), an increased secretion of glucagon by the pancreas promotes the breakdown of glycogen and release glucose (glycogenolysis)

Type 1 diabetes – insulin-dependent diabetes, common in children Too much glucose, little or no insulin

(mutation, no insulin made or non-functional), glucose excreted in urine

Type 2 diabetes – insulin-independent diabetes, adult onset Normal or elevated levels of insulin, but

cells no longer respond to the insulin Insulin is the only hormone that

decreases glucose in the body