Bio Exam Review

What is an autotroph?

Harness light to build organic molecules (ex: plants)

What is a heterotroph?

Obtain chemical energy from food (ex: animals)

Definition of bioenergetics?

the overall flow and transformation of energy in an animal (autotrophs and heterotrophs)

What is metabolic rate?

sum of all energy used by an animal over time

How is metabolic rate measured?

Heat loss and oxygen consumption

What is the difference between Basal and Standard metabolic rate?

BMR is for warm blooded or endotherms. SMR is for cold blooded or ectotherms

How is mass related to BMR?

The smaller the animal, the less energy needed to feed it, but the smaller animals eat more than its body mass than large animals.

What are the 3 things that consist of an animal's diet?

Chemical energy, Organic building blocks, and essential Nutrients

What is ATP?

carbohydrates, fats and proteins

What are building blocks?

sugars and protein amino acids

What are essential nutrients and why are they essential?

They are vitamins, minerals, and trace elements. They are essential because our body cannot make them on our own.

What is considered ingestion?

Bulk, filter, fluid, and substrate feed

What is digestion?

Mechanical chewing and grinding of food and breaking down food via chemical processes.

What does the pancreas do?

Protein digesting enzymes are secreted from the pancreas into the small intestine

What does the liver do?

Regulates distribution of amino acids into body

Why do we chew our food?

To break food into smaller pieces to increase surface area. Also the enzyme amylase in saliva breaks down starches.

Order for digestion

Oral cavity -> Pharynx -> Esophagus

What happens during chemical digestion?

Stomach has HCL (hydrochloric acid), is very acidic pH, and unfolds proteins to allow pepsin enzyme to attack bonds

What's the duodenum?

beginning of s.i. where product of stomach mixes with enzymes from pancreas, liver and gallbladder

What is villi?

folds on the small intestine lining that increase the surface area to facilitate the absorption of nutrients

Where does the most digestion occur?

Small intestine

What is in the large intestine?

Includes Colon, cecum and rectum. Cecum is important for fermentation of plant material. Colon aids in recovery of water

What is in the small intestine?

Jejunum and ileum

What is gastrovascular cavity?

Only one opening for digestion. Cells within cavity secrete digestive enzymes. (Think of a starfish)

What is an alimentary canal?

More advanced, unidirectional than a gastrovascular cavity. Food is stored in crop, mechanically digested in gizzard

What is rumination and are examples of ruminants?

regurgitation and remastication of undigested fibrous material from rumen, which is then swallowed again. (cattle, sheep, camels, and goats)

What is a rumen?

\- Large fermentation vat filled with bacteria and protozoans that break down cellulose.

What is a reticulum do?

Further fermentation after rumen

What does the omasum do?

absorb volatile fatty acids and digests protozoans

What does the abomasum do?

secretes digestive enzymes and where true digestion takes place

What are pseudo-ruminants?

Modified digestive tracts with compartments that contain microorganisms. Some have enlarged and modified stomachs to accommodate fermentation; others have cecum, which is a large pouch from the lower intestine (site of fermentation)

Describe the avian digestive system

They do not have teeth so they swallow the food, store it in a place called the crop, release digestive enzymes called proventriculus, and grind the food in the gizzard.

How do we regulate food intake? (there are three)

Blood sugar level, we 'feel' full when our stomach is filled, and the hypothalamus part of the brain tells us when we need to eat

Describe single circulation

Has a single pump (atrium and ventricle), Single circuit, Slower pace of circulation, includes Fishes (bony and cartilaginous fishes)

Describe double circulation

2 circuits - systemic and pulmonary (or pulmocutaneous). Right side heart pumps blood to lungs. Left side pumps O2 blood to body

What is a myogenic?

A pacemaker. Includes the sinoatrial and atrioventricular node

What is the difference between an artery and vein?

Arteries are thick, strong, and elastic. They accommodate high blood pressure and regulate blood flow. Veins have thinner walls and return blood at lower pressure

What is a capillary?

Smallest site for diffusion. Includes every cell in close proximity

What is in plasma and what is its function?

Ions and proteins. Plasma helps with osmotic regulation, transport, defense, and buffer pH changes

In addition to plasma, what else is in blood?

Platelets, red blood cells, and white blood cells

What is blood coagulation?

Important to prevent loss of blood from ruptured vessel. Loss is prevented by vessel constriction and coagulation.

What is an enzyme cascade?

allows clotting to take place quickly but with a considerable safety margin to prevent spontaneous coagulation!

What is an excitable cell?

Responds to defined stimulus by altering electrical properties of cell membrane.

What does the nervous system do?

Nervous systems evolved to permit organisms to absorb information, process it, and respond rapidly. The basic component of all nervous systems is the neuron or nerve cell.

What is an afferent neuron?

sensory neurons connected to receptors; occur in the peripheral nervous system

What is an efferent neuron?

motor neurons connected to effectors (such as muscles or glands) in the peripheral nervous system

What are interneurons?

connect neurons to other neurons; lie almost entirely within the central nervous system

What is the membrane resting potential for nerve cell function?

\-50 to -80 mV. During this time, membrane is selectively permeable to potassium

Describe membrane resting potential

Because of concentration differences, K+ will diffuse out of cell, leaving a net positive charge on outside of cell and a net negative charge on inside (Cl- cannot accompany K+ across membrane).

Describe action potentials

large brief changes in membrane voltage that are propagated along an axon, sometimes over a long distance without decrement. Membrane becomes permeable to Na+ Membrane Potential changes from rest (approximately -70 m) to +35 to +55mV

Definition of all or none response

A stimulus causes either a full strength action potential or none at all

What is conductance without decrement?

Because the action potential results from the local concentrations of ions, it spreads along the axon without change in magnitude.

Which two animals have giant axons?

Squid and cockroaches

What is myelin?

Vertebrates do not have giant axons; instead they have axons that are wrapped in myelin. Myelin acts like insulation so that current can pass virtuously instantaneously from node to node.

What is saltatory conduction?

The rapid transmission from node to node

Define diffusion

Most important process in the movement of oxygen from the external medium to the cells is diffusion

Describe tracheae or insect respiration

Insects have a hard cuticle covered with wax, which is often highly impermeable to gases and water. Gas exchange takes place through a system of air-filled tubes, the tracheae, which connect to the outside by openings known as spiracles. The tracheal system delivers oxygen directly to the tissues and takes up carbon dioxide. Respiration is independent of blood and the circulatory system.

What is a gill and the three types of gills?

Outfolding of body surface and has a high surface area Tufted, Filament, and Lamellar

What is ventilation?

movement of water over gills

What is alveoli?

Mammalian lung is finely divided up into small sacs, known as alveoli, that vastly increase surface area available for gas exchange.

What are surfactants?

prevent alveoli from collapsing under surface tension

Order of air going through the mammalian respiratory system

Nasal cavity & pharynx, trachea, bronchi, bronchioles, alveoli (site of gas exchange), and capillaries

The lung volume of a mammal constitutes about __ % of the body volume, irrespective of body size

5%

Describe bird respiration

Lungs are small and compact, and they connect to thin-walled air sacs that are distributed throughout body Birds do not have alveoli, but rather small tubes known as parabronchi that permit through passage of air.

Describe the type of gas exchange for fish, birds, and mammals in order

Countercurrent, crosscurrent, and uniform

Why is the ventilation of the lungs adjusted by carbon dioxide concentration in the lungs and not oxygen?

Because of the high availability of oxygen in atmosphere, a decrease in oxygen is not particularly deleterious (21% --> 16% has little effect) . However, a small increase in CO2 (1%) has a significant physiological effect - it increases carbonic acid by 25%!

Define osmosis

Regulating chemical composition of body fluids. Balancing uptake and loss of water and solutes

What is osmotic pressure?

pressure created by osmosis between two solutions separated by a semipermeable membrane.

Osmolarity

Solute concentration (moles/liter)

Isoosmotic

having body fluids with same osmotic pressure as the medium in which the animal lives.

Hyperosmotic

having body fluids that are more concentrated than the surrounding medium.

Hypoosmotic

having body fluids that are less concentrated than the surrounding medium.

Osmoconformer

organism whose body fluids conform with that of the surrounding medium. Always isoosmotic

Osmoregulator

organism that maintains/regulates its osmotic concentration independently of external concentration changes.

Euryhaline

animals that tolerate wide variations in salt concentrations in which they live.

Stenohaline

animals that have a limited tolerance to variations in salt concentrations in which they live.

What is the osmoregulation of marine invertebrates?

Most marine invertebrates are osmoconformers and thus do not have to cope with osmotic movement of water. However, this does not mean that their blood and other body fluids have same solute composition as seawater!

What is the osmoregulation of marine teleost fish?

Hypoosmotic. Excess salt is eliminated by active transport at the gills

What is the osmoregulation of marine elasmobranchs (sharks and rays?)

Elasmobranchs still rely on extensive ionic regulation; sodium excretion is handled by kidney, rectal gland, and gills. Elasmobranchs maintain salt concentrations in their body fluids at about 1/3 the level of seawater, but they maintain osmotic equilibrium (slightly hyperosmotic) using urea and other organic compounds (e.g., TMAO). Therefore, elasmobranchs are osmoconformers and strong ionic regulators!

What is the osmoregulation of freshwater animals and freshwater teleost fish?

Freshwater animals are all hyperosmotic regulators

How do marine air breathing vertebrates get rid of excess salt?

All marine birds have paired nasal salt glands that, through a duct, connect with the nasal cavity. The salt glands are inactive and start secreting only in response to osmotic stress.

Describe excretion

Nitrogenous waste reflects habitat. Most metabolic wastes are dissolved in water for excretion. Significant component is nitrogenous breakdown products of proteins and nucleic acids

Describe the excretory process for insects step by step

Malpighian tubules remove nitrogenous wastes and do osmoregulation. Filtration step absent for insects. Immersed in hemolymph. Salt, nitrogenous wastes, and water enter tubules and are passing into the rectum

Describe the excretory process for vertebrates

Kidneys function in both osmoregulation and excretion. Pair kidneys > urine exits through ureter > drain into urinary bladder > exits through urethra

What is the nephron? How does this fit into the function of kidneys?

Nephron is a single long tube and ball of capillaries (glomerulus) surrounded by Bowman's capsule. Filtrate is fluid forced from blood into Bowman's capsule. Processed as filtrate passes through proximal tubule, loop of Henle, and distal tubule. Collecting duct receives filtrate

What does each part of the collecting tube from the kidneys do?

Filtrate in Bowman's capsule contains salts, glucose, amino acids, vitamins and other small molecules. Proximal tubule-->recapture ions, water and nutrients. Descending Loop of Henle --> recapture water. Ascending Loop of Henle --> removal NaCl from filtrate. Distal tubule --> regulation of K and NaCl --> Collecting duct --> process into urine

Synapse

the point where an axon makes contact with another neuron.

Electrical synapse

terminal end of axon close to membrane of next neuron. Conduction involves electrical current and involves rapid transmission. Found in vertebrate retina, vertebrate central nervous system, smooth muscle fibers, cardiac muscle, sensory receptor cells

Chemical synapses

most common. Conduction occurs in one direction only and involves chemicals. There is a synaptic cleft that is 20-30 nm. The transmission of an impulse from the presynaptic knob to the postsynaptic neuron is achieved through the release of a chemical transmitter substance from the synaptic vesicles. The calcium channels are voltage-gated, and the sodium channels are chemically-gated.

Describe the process of chemical synaptic transmission

Depolarization of presynaptic axon --> Voltage gated channels allow Ca+ in --> Vesicles fuse with presynaptic membrane and release chemical transmitter --> Chemical transmitter opens ligand gated channels allowing Na+ through postsynaptic membrane = Post synaptic potential (PSP)

Acetylcholine -

best known transmitter substance, especially for neuromuscular synapses. Magnitude of PSP seems to be directly related to the amount of Acetylcholine released. These neurotransmitters are released in 'packet' called quanta, which are roughly equal to the amount in a vesicle.

Acetylcholinesterase

always present and serves to remove/destroy the transmitter to prevent buildup.

Temporal Summation

If several impulses arrive at the same axon terminal before PSP has decayed, the amount of the transmitter substance increases and PSP increases. Amplitude of PSP depends on frequency of the action potentials. The PSP is a frequency modulated potential.

Spatial Summation

occurs when a new PSP enters an area and adds to the existing potential.

How is the Central Nervous System developed?

CNS develops from hollow nerve cord during embryonic development and includes the Central canal of spinal cord, Ventricles of the brain, and Cerebrospinal fluid

Describe the function of the peripheral nervous system

Transmits info to and from CNS. Includes the afferent, efferent, and enteric nervous system

3 parts of the central nervous system and what they do

Forebrain - thalamus, hypothalamus, cerebrum. Midbrain - coordinates the routing of sensory input. Hindbrain - medulla oblongata, and cerebellum (involuntary activities and motor activities)

Arousal vs sleep?

Arousal is awareness of external env and sleep is when external stimuli are received but not perceived

Function of sleep?

Consolidate learning

What does the cerebrum do?

Language, memory, consciousness, cognition, and awareness. Regional specialization includes the: Sensory areas, Association areas, and Motor areas