Viruses and Bacteria

The success of some viruses lies in their ability to evolve rapidly within the host. Such a virus evades the host's defenses by mutating and producing many altered progeny viruses before the body can mount an attack. Thus, the viruses present late in the infection differ from thoses that initially infected the body. Discuss this as an example of evolution in microcosm. Which viral lineages tend to predominate?

Please post your answer and discussion to the question.

Glogster

Viruses and Bacteria

Health officials worldwide are concerned about antibiotic resistance in bacteria that cause disease. In patients infected with nonresistant strains of the bacterium that causes tuberculosis, antibiotics can relieve symptoms in a few weeks. However, it takes much longer to halt the infection, and patients may discontinue treatment while bacteria are still present. How can bacteria quickly cause symptoms again if they are not wiped out? How might this result in the evolution of drug-resistant pathogens?

Please post your answers to these questions.

Trimester 2

We will start Trimester 2 with some new guidelines:
1. Summarize your notes
2. Add pictures with ATTRIBUTIONS
3. Try a new type of technology application. Voki, glogster, wordle, animoto, prezi, etc

You will not need to write quiz questions

I will also be posing questions that I would like you to post comments. If your post is well thought out, but only partially correct, then you will still receive some extra points.

Happy Blogging!

Action Potential and Germ Layers

action potential and diagram

Action potential=nerve impulse

• All-or-none event
• Size of action potential not affected by strength of triggering stimulus

Action Potential in a Neuron

1. Environmental changes alter cell’s membrane potential
2. Neuron hyperpolarized by stimuli that open potassium channels, or
3. Neuron hyperpolarized by stimuli that open sodium channels
4. Depolarizing stimulus of sufficient strength will change the membrane potential to critical level (threshold potential)
5. Triggers action potential

The role of voltage-gated ion channels in the action potential

1. Resting state
1. Both sodium and potassium channels are closed
2. Resting potential of membrane is maintained
2. Threshold
1. Stimulus opens some sodium channels
2. Sodium influx achieves threshold potential
3. Additional sodium gates open
4. Triggering action potential
3. Depolarization phase of the action potential
1. Activation gates of sodium channels are open
2. Potassium channels remain closed
3. Sodium ions rush into cell
4. Interior of cell becomes more positive
4. Repolarization phase of the action potential
1. Inactivation gates close sodium channels
2. Potassium channels open
3. Potassium ions leave the cell
4. Loss of positive charge causes inside of cell to become negative relative to outside
5. Undershoot
1. Both gates of sodium channels are closed
2. Potassium channels remain open

i. Relatively slow gates have not had time to respond to the repolarization of the membrane

3. Resting state restored within another 1-2 milliseconds
4. Ready to respond to another stimulus

(Diagram p. 1030)

Chemically-gated ion channels open or close in response to a chemical stimulus

• Neurotransmitter released from synaptic terminal

Voltage-gated ion channels respond to a change in membrane potential

An action potential is an example of positive feedback

Potassium channel gates are the main cause of undershoot, or hyperpolarization

The refractory period sets the limit on the maximum frequency with which action potentials caan be generated

Strong stimuli result in a greater frequency of action potentials than weaker stimuli

The number of action potentials per second, not their amplitude, code for stimulus intensity in the nervous system

germ layers

Embryo becomes layered through the process of gastrulation

• Rearrangement of the embryo
• One end of the embryo folds inward, expands, fills the blastocoel
• Producing layers of embryonic tissues
• Ectoderm: outer layer
• Endoderm: inner layer

Germ layers=concentric layers

• Form various tissues and organs of the body

1. Ectoderm
1. Covers surface of embryo
2. Gives rise to outer coverings of the embryo
3. Origin of nervous system
2. Endoderm
1. Innermost germ layer
2. Lines developing digestive tube (archenteron)
3. Gives rise to lining of digestive tract and organs derived from it

i. Liver

ii. Lungs

3. Mesoderm
1. Third germ layer
2. Between endoderm and ectoderm
3. Forms muscles
4. Forms most organs between digestive tube and outer covering of the animal

Quiz:

1. The outer-to-inner sequence of tissue layers in a post-gastrulation vertebrate embryo is

a. ectoderm->endoderm->mesoderm

b. endoderm->ectoderm->mesoderm

c. endoderm->mesoderm->ectoderm

d. mesoderm->endoderm->ectoderm

e. ectoderm->mesoderm->endoderm

2. The "threshold" potential of a membrane

a. is the minimum hyperpolarization needed to prevent the occurrence of action potentials

b. is the peak amount of depolarization seen in an action potential

c. is the lowest frequency of action potentials a neuron can produce

d. is the point of separation from a living to a dead neuron

e. is the minimum depolarization needed to operate the voltage-gated sodium and potassium channels

Answers: 1e, 2e

A Review of Chapter 44

QUIZ OVER CH. 44

MAINTAINING HOMEOSTASIS

1. Homeostasis refers to an animal's ability to regulate it's _________ __________.

2. Asmoregulation refers to how animals regulate their solute balance and water content. (True or False?)

3. What is the difference between vasodilation and vasoconstriction?

4. Name 2 other ways thermoregulation can take place.

5. What is thermoregulation?

WATER BALANCE & WASTE DISPOSAL

1. Metabolic wastes must be excreted from the body. (True or false?)

2. Mammals have ___ (#) kidneys and each is supplied with a renal artery and a renal vein.

3. How does urine leave the kidney? (Hint: it drains into the urinary bladder)

4. Although, urine is expelled from the body through the ____________.

5. What are the 2 regions of the kidney called?

6. The Bowman's capsule is a ball of capillaries? (True or false?)

7.In the decending loop (Loop of Henle) water moves out by osmosis and H20 moves ACTIVELY or PASSIVELY?

8. Urine is filtered blood (True or False?)

9. Ultra Filtrate is NOT selective in the Bowman's capsule. (True or False?)

10. What are the 2 places that secrection can only happen?

11. Explain the importance of ADH. (Anti Diaretic Hormone)

ANSWERS:

HOMEOSTASIS SECTION:

1. internal environment

2. True

3. Vasodilation is an increase in diameter of blood vessels at the skin, which cools the blood. Vasoconstriction is the opposite of vasodilation; constriction of the blood vessels.

4. Thermoregulation can take place by a) ajusting the rate of heat exchange between and animal and it's environment or b) Evaporation across the skin (through panting or sweating) or c) behavioral responses (changes in location or posture) or d) alteration of the rate of metabolic heat production (only in endotherms)

5. Thermoregulation refers to how animals maintain their internal temperature

WATER & WASTE DISPOSAL SECTION:

1. True

2. 2 kidneys

3.Urine leaves the kidneys through the ureters

4. Urine is expelled from the body through the urethra.

5. The 2 regions of the kidney are called the outer cortex renal cortex and the inner renal cortex. These 2 regions are packed with nephrons, which are the functional untit of the kidney.

6. False, the glomerulus is a ball of capillaries. The Bowman's capsule is a C-shaped capsule that surrounds the glomerulus.

*I found this great video which reviews the urinary system but I can't figure out how to upload it so heres the web link: http://www.youtube.com/watch?v=qxb2_d9ilEw

7. Passively

8.True

9. True

10. The proximal and distal tubule are teh onyl places that secretion can happen

11. ADH is an important hormone in the regulation of water balance. It is produced in the hypothalmus and sotred in and released from the pituatary gland. 2 other hormones involved in regulation of water balance are angiotensin and aldosterone. ADH is always produced, not always released.

*To the right is the process of ADH (http://www.virtualcancercentre.com/uploads/VMC/DiseaseImages/600_SIADH.jpg)

Review Questions Digestive System

1. Which of the following is connective tissue?

A) muscle

B) internal organs

C) hair

D) blood

2. What are the four types of tissue?

3. What is interstitial fluid?

4. What is difference between endotherm and ectotherms?

5. What is first step of Human Digestive system?

A) digestion

B) ingestion

C) Elimination

D) Absorption

6. What is difference between intracellular and extracellular digestion?

7. Where does ingestion occur?

A) mouth

B) stomach

C) small intestine

D) all of the above

8.Where do carbohydrates begin to break down?

A) stomach

B) small intestine

C) colon

D) mouth

9. What enzyme breaks down protein in the stomach?

A) amylase

B) gastrin

C) chyme

D) pepsin

10. Where is all the nutrients from food absorbed?

A) stomach

B) small intestine

C) large intestine

11. Where is bile produced and where is it stored?

12. Where are fats digested?

A) mouth

B) large intestine

C) stomach

D) small intestine

12. What does the hormone gastrin do?

13. Which specific structure is primary site of digestion in small intestine?

14. Where does all blood from the villi go?

15. What is the main function of the colon?

Answers:

1. D 2. epithelial, connective, nervous, muscle, 3. the internal environment of the animal 4. endotherms warm body from own body heat while ectotherms rely on the environment to regulate their temp 5. B 6. Intracellular- material is broken down inside cell, Extracellular- material is broken down outside cell first then absorbed 7. A 8. D 9. D 10. B 11. produced in liver and stored in gall bladder 12. Stimulates the release of gastric juice in the stomach 13. The villi

14. join at the hepatic portal vessel and continues on to the liver 15. recover water from waste

Evolution Exam Review

A POPULATION IS THE SMALLEST UNIT THAT CAN EVOLVE

Darwin:

born/died- 1809-1882

1831- sailed on the Beagle, spent most of his time on shore studying the plants and animals off the coast of South America.

- noted that the plants and animals intemperate regions of south America were more closely related to South American tropics than species in temperate Europe.

- the fossils he found, though different from the living species he studied, there was a resemblance between the fossils in South America and the species in South America, not the same as the species or fossils in Europe

- published his theory in The Origin of Species

- evolution explains life's unity and diversity

- natural selection is a cause of adaptive evolution

* Darwin did not use the word evolution until the very end of his book, but instead used Descent with modification (Darwin's view of life)

Evolution:

- All the changes that have transformed life on earth from its earliest beginnings to the diversity that characterizes it today.

Gradualism- a view of earth's history that attributes profound change to the cumulative product of slow but continuous processes

Common Ancestor- descend from a common gene pool

Natural Selection- differential success in the production of different phenotypes resulting from the interaction of organisms with their environment. evolution occurs when natural selection causes changes in relative frequencies of alleles in the gene pool

Variation- differences between members of the same species

Homologous Structures- structures in different species that are similar because of common ancestry

Analogous Structures- structures in different species that are similar because of convergent evolution

Genetic Drift- unpredictable fluctuations in allele frequencies from one generation to the next because of a populations finite size

Adaptive Radiation- the emergence of numerous species from a common ancestor introduced into an environment that presents a diversity of new opportunities and challenges

Modes of Natural Selection

- Directional Selection: favors individuals at one end of the phenotypic selection

- Stabilizing Selection: favors intermediate variants by acting against extreme phenotypes

- Diversifying Selection: favors extreme over intermediate phenotypes

Hardy-Weinberg Equilibrium: the condition describing a non-evolving population (one that is in genetic equilibrium)

- p2+2pq+q2=1

- p+q=1

- p= frequency of the dominant allele in the population

- q= frequency of the recessive allele in the population

- p2= percentage of homozygous dominant individuals

- q2= percentage of homozygous recessive individuals

- 2pq= percentage of heterozygote individuals

Punctuated Equilibrium- in evolutionary theory, long periods of apparent stasis (no change) interrupted by relatively brief periods of sudden change

Bottlenect Effect- genetic drift resulting from the reduction of a population, typically by a natural disaster, such that surviving population is no longer genetically representative of the original population

Founder Effect- genetic drift that occurs when a few individuals become isolated from a longer population with the results that the new populations gene pool is not reflective of the original population

1. what is generally true of two very closely related species that have diverged from each other quite recently?

a. they are unable to produce hybrid offspring upon interbreeding

b. their reproductive isolation from each other is complete

c. they share a common ancestor recently in evolutionary time

d. genes are unable to pass from one species' gene pool to the other's gene pool

2. if the curve shifts to the left or to the right, there is no gene flow, and the population size consequently increases over successive generations, then which of these is (are) probably occurring?

a. directional selection

b. adaption

c. all of the above

d. none of the above

3. the ability to roll one's tongue, allele (R), is dominant over the absence of this ability, allele (r). in a population of 1000 people, 640 have the ability and 360 do not. what is the frequency of allele (r) in this population? (assume HW equilibrium)

a. .7

b. .6

c. .64

d. .36

1. c, 2. c, 3. b

Trimester Exam

TRIMESTER EXAM!!!!
Study old tests, quizzes, vocabulary and the words/processes below.


EVOLUTION:
Darwin
gradualism
common ancestor
natural selection
variation
homologous/analogous structures
genetic drift
adaptive radiation
modes of natural selection

****Know Darwin! Look at pictures/Examples
Hardy-Weinberg
punctuated equilibrium
artificial selection or genetic engineering

A & P:
antagonistic hormones
ectotherms
endotherms
nephron (filtrate,etc) and diagram
action potential and diagram
germ layers
sliding filament
carbon dioxide and gas exchange in blood
synapse
pathway of blood oxygenated/deoxygenated
digestive enzymes
regulatory filtrate hormones
actin/myosin
major A &P organs (stomach, kidney, etc)- structure and function
sarcomere diagram
gamete production
sexual reproduction hormones (male and female)
stages of zygotic division
antigens

Video by Meredith

New Material + Review

http://animoto.com/play/ojRdjv8pcmQRNI0B3x87Mw?utm_source=project_complete_email&utm_medium=email&utm_campaign=project_complete_email&utm_content=challenger#

http://staff.washington.edu/cdave/pbio505/images/saltatory.jpghttp://images.google.com/imgres?imgurl=http://nasw.org/users/dsteele/Stories/hair_cell.jpg&imgrefurl=http://www.nasw.org/users/dsteele/Stories/Humming_along3.html&usg=__XuZXMmh-FYD1qeCt8QYRa6i1PwE=&h=320&w=318&sz=24&hl=en&start=11&um=1&tbnid=TG1D-g7fhLuE8M:&tbnh=118&tbnw=117&prev=/images%3Fq%3Dhair%2Bcell%26hl%3Den%26client%3Dsafari%26rls%3Den%26sa%3DN%26um%3D1http://www.ks.uiuc.edu/Research/telethonin/MuscleL1.jpghttp://www.colorado.edu/intphys/Class/IPHY3430-200/image/08-20.jpg

Resting potential

• membrane potential of a nerve cell at rest
• exists because of differences in the ionic composition of the extracellular & intracellular fluids of the axonal membrane
• *Changes in the axonal membrane potential of a neuron are what give rise to nerve impulses.

Stimulus affects the membrane's permeability to ions.

• graded potential with a magnitude proportional to the size of the stimulus
• *stimulus permeability to Na+ and K+
• *Why do we have membranes? To BALANCE us

Action potential (nerve impulses)

• the all-or-none depolarization of the membrane of a nerve cell
• opens voltage-gated sodium channels
• Na+ ions enter the cell --> bringing membrane potential to a positive value
• Na+ gates then close --> cell returns to a resting potential
• potassium pump helps return to resting potential

Saltatory conduction- rapid transmission of nerve impulse along an axon resulting from the action potential the action potential jumping from one node of Ranvier to another, skipping the myelin-sheathed regions of the membrane.

• action potentials are propagated along the axon
• jumping of nerve impulse between nodes of Ranvier (areas on the axon NOT COVERED by myelin sheaths = accelerated conduction of the nerve impulse
• What triggers jumping?
• the signal is conducted from the axon of a presynaptic cell to the dendrite of a postsynaptic cell via an electrical or chemical synapse (electrical=ion) (chemical=acetecholyine? Please comment if I am wrong!)

IPSP

• voltage charge associated with chemical signaling at an inhibitory synapse

New Material Multiple Choice

1. After the depolarization of an action potential, repolarization occurs due to the

a. closing of sodium activation and inactivation gates.

b. opening of the sodium activation gates.

c. refractory period in which the membrane is hyperpolarized.

d. delay in the action of the sodium-potassium pump.

e. opening of voltage-gated potassium channels and the closing of sodium channels.

2. The function of motor neurons is to carry impulses

a. form the spinal cord to the brain

b. from the cerebellum to the cerebrum.

c. from sensory receptors to the spinal cord.

d. from the CNS to effectors (muscles and organs.)

e. between interneurons and the PNS.

3. Movement of an action potential in only one direction along a neuron is a function of

a. saltatory conduction

b. the pathway from dendrite to axon.

c. the refractory period when sodium inactivation gates are still closed.

d. the localized depolarization of the surrounding membrane.

e. the formation of threshold potential, which creates an all-or-none firing.

ANSWERS

1. e

2. d

3. c

Review!

A band- the broad region that corresponds with the thick filaments

I band- the area near the edge of the sarcomere where there are only thin filaments

Hair cell- a type of mechanoreceptor that detects sound waves and other forms of movement in air or water

Interoreceptor- sensory receptors that detect stimuli within the body, such as blood pressure and body position.

depolarization- an electrical state in an excitable cell whereby the inside of the cell is made less negative relative to the outside rather than the resting membrane potential

Action potential- a rapid change in the membrane potential of an excitable cell

Nephron- the tubular excretory unit of the kidney

Collecting duct- where filtrate from the renal tubule is collected; filtrate is now urine

Ectotherm reabsorption- an animal that must use environmental energy and behavioral adaptations to regulate its body temperature

Conformers- a characterization of an animal in regard to environmental variables

Systemic circulation- the branch of the circulatory system that supplies all body organs and then returns oxygen-poor blood to the right atrium via the veins

Double circulation - the circulation scheme with separate pulmonary and systemic circuits , which ensures vigorous blood flow to all organs

carboxypeptidase- an enzyme found within the small intestine that splits off one amino acid at a time starting with a carboxyl end

sympatric speciation- a mode of speciation occurring as a result of a radical change in the genome of a subpopulation, reproductively isolating the population

adaptive radiation- the emergence of numerous species from a common ancestor introduced into an environment, presenting diversity of new problems

Review Multiple Choice

1. What would be expected if the amount of interstitial fluid surrounding the capillary beds of the lungs were to increase significantly?

a. the amount of oxygen entering the circulation from the lungs would increase.

b. the amount of carbon dioxide entering the lungs from the blood would increase.

c. the amount of oxygen entering the circulation from the lungs would decrease.

d. the pressure would cause the capillary beds to burst.

e. both C and D would be expected.

2. Which of the following is the last line of defense against an extracellular pathogen?

a. phagocytosis by neutrophils

b. antibody production by plasma cells

c. lysozyme production

d. lysis by natural cell killers

e. histamine release by basophils

3. Increasing the surface area directly facilitates which of the following digestive processes?

a. elimination

b. absorption

c. hydrolysis

d. A and B only

e. A, B, and C

4. The origin of a new plant species by hybridization coupled with accidents during nuclear division, is an example of

a. autopolyploidy

b. allopatric speciation

c. sympatric speciation

d. habitat selection

ANSWERS

1. C, because interstitial fluid surrounds cells and is therefore outside of cells. Inter = between.

2. B, because your immunoglobulins. First part the defense is physical, using cilia and mucous. Second line of defense uses your T-cells. The last line of defense is for your body to mount an immune response with antibodies.

3. D, because elimination refers to the ascending colon, inner foldings, and the large intestine. Elimination and absorption are directly related. Excess water will be expelled as urine, and the more you absorb, the less you eliminate. The answer would not be hydrolysis, which utilizes water to break down materials. Please comment if I am wrong!

4. C, because hybridization refers to two different parents.

Ch 48. Nervous Systems

1. Neuron
ww2.cedarcrest.edu/.../tetanus-neuron.gif

• Functional Unit of the nervous system.



• Composed of a Cell body

Dendrite

• Cell extensions that receive incoming messages
  

Axon

• conducts electrical impulses away from the neuron's cell body



• covered by fatty myelin sheath

Synaptic Terminals

• at the end of axons



• relay messages through neruotransmitters

2. Action Potential

http://content.answers.com/main/content/img/oxford/Oxford_Sports/0199210896.action-potential.1.jpg

• axon--->dendrite



• Sodium moves in ( NA+ OUT)



• Potassium moves out (K+ IN)

1. When an axon is at resting potential, it sits at -70mv.



2. When stimulated, sodium gates open which depolarizes the membrane making it less negative.



3. If the membrane reaches -55mv or threshold potential, then an action potential will occur.



4. The sodium gates will close at the peak of the action potential while potassium ions continue to leave the cell.



5. The outward flow of potassium ions decreases the membrane potential or hyperpolarizes the cell.

Nerve Transmission

• Pre-synaptic cells transmit



• Post synaptic cells receive

IPSP-Inhibitory

• opens potassium channels



• potassium does not allow threshold potential because it is less positive than sodium

EPSP-Excitatory

• Sodium gates open which allow threshold potential to be reached



• once threshold potential is reached, an action potential will occur

Chapter 47: The Three Stages of Early Embryonic Development

cleavage-gastrulation-organogenesis

1. Cleavage-

• rapid miotic division
• cuts cytoplasm of zygote into blastomeres (each has its own nucleus)
• forms a ball of cells called a morula
• a fluid filled cavity, a blastocoel, forms within the morula to make a blastula

2. Gastrulation-

• rearrangement of cells in blastula
• the 3 germ layers (ectoderm, mesoderm, and endoderm) are produced
• ectoderm- beginning of nervous system and outer layer of skin
• mesoderm- skeleton, most organs and tissues
• endoderm- digestive system

3. Organogenesis

• development of the three germ layers into rudiments of organs

http://www.youtube.com/watch?v=UgT5rUQ9EmQ&feature=related

embryonic development video!!

Sexual Reproduction

Female



Oogenesis- The development of mature ova



Oogonia- Cells that develop into ova

• Multiply and begin meiosis


• STOP at prophase 1 of meiosis 1


• These egg cells are called primary oocytes which are quiescent until puberty
  

Humans and other primates have menstrual cycles while other mammals have estrous cycles. Menstruation occurs when the endometrium is shed from the uterus through tyhe cervix and vagina

Menstrual Flow Phase- Phase during which menstrual bleeding occurs.

Proliferative Phase- The endometrium begins to regenerate and thicken

Secretory Phase- Endometrium continues to thicken, and if an embryo has not implanted in the lining by the end of this phase, menstrual flow occurs.

Ovarian Cycle: This parallels the menstrual flow cycle, begins with follecular phase, in which several follicles begin to grow. At the end of the follecular phase, ovulation occurs, during which the secondary oocyte is released from the ovary.

QUIZ

1. Ovulation is the follicular response to a burst of secretion of

1. Prolactin
2. LH
3. Estradiol
4. Pregesterone
5. Inhibin

2. Fertilization normally

1. Reinstates diploidy
2. Precedes ovulation
3. Merges two diploid cells into one haploid cell
4. follows gastrulation
5. Is required for parthenogenesis

3. The sequence of developmental milestones proceeds as follows:

1. Cleavage --> Blastula --> Gastrula --> Morula
2. Morula --> Cleavage --> Gastrula --> Blastula
3. Gastrula --> Morula --> Blastula --> Cleavage
4. Cleavage --> Gastrula -->Morula --> Blastula
5. Cleavage --> Morula --> Blastula --> Gastrula

4. At the time of implantation, the human embryo is called a

1. Gastrula
2. Somite
3. Zygote
4. Blastocyst
5. Fetus

Answers: 2, 1, 5, 4