AP BIOLOGY 2019-20 November 7, 2019

Today’s Agenda (Day 51)1. Homework Check:

Chapter 47 Notes Chapter 48 Notes

2. Class Activity: TEST: Chapter 47 & 48

HOMEWORK: Read Unit 4 Chapters on Genetics: Chapters 13 - 16 Complete Chapter 13 Vocabulary – definition AND sentence/example/image ONLY

Chapter 47 – Animal Developmentacrosomal reaction animal pole apical ectodermal

ridgeblastocoel blastocyst blastomeres

Blastula convergent extension Ectoderm Endoderm extraembryonic membranes

fate maps

fertilization Gastrulation germ layers Mesoderm neural tube NotochordOrganogenesis positional

informationslow block to polyspermy

Trophoblast vegetal pole Yolk

zone of polarizing activity

Chapter 48 – Neurons, Synapses and Signalingaction potential Axon central nervous

systemDendrites Depolarization excitatory post-

synaptic potentialGlia graded potentials Hyperpolarization inhibitory post-

synaptic potentialmembrane potential Myelination

Neurotransmitter node or Ranvier peripheral nervous system

refractory period resting potential saltatory conduction

spatial summation Synapses temporal summation Threshold voltage-gated ion channels

Chapter 13 – Meiosis and Sexual Life CyclesAnaphase I Asexual reproduction Autosomes Chiasmata Crossing overDiploid Gene Haploid gametes Homologous LocusMeiosis Meiosis I Meiosis II Metaphase I Prophase ISex chromosomes Sexual reproduction Somatic cells Synapsis zygote

Chapter 14 – Mendel and the Gene IdeaAddition rule Alleles Amniocentesis Carriers Chorionic villus

samplingDihybrids

Dominant allele Heterozygotes Homozygotes Law of independent assortment

Law of segregation Monohybrids

Multifactorial Multiplication rule Pedigrees Recessive allele True breeding

REMINDERS: Chapter 47 & 48 Vocabulary Quiz November 5 Postponed Chapter 13 Vocabulary – November 9 Chapter 13 Notes – November 12 Chapter 14 Vocabulary – November 13 Chapter 14 Notes – November 14 TEST: Ch 47 & 48 November 7 TEST: Ch 13 & 14 November 19

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AP BIOLOGY 2019-20 READING GUIDE

Chapter 47: Animal Development Overview

1. An organism’s development is controlled by the genome of the zygote as well as by molecules from the mother that are in the cytoplasm of the egg. What are these proteins and RNAs called?

2. What is cell differentiation?

3. How do cytoplasmic determinants affect cell differentiation?

4. What is morphogenesis?

Concept 47.1 After fertilization, embryonic development proceeds through cleavage, gastrulation, and organogenesis

5. What is the acrosome of a sperm? What does it contain?

6. The figure below shows sea urchin fertilization. Label the following: sperm acrosome, sperm nucleus, jelly coat of egg, sperm-binding receptors, cortical granules, vitelline layer, egg plasma membrane, and fertilization envelope.

7. Describe what happens in the acrosomal reaction.

8. The fusion of the egg and sperm plasma membranes allows sodium ions to flow into the egg. How does

this result in a fast block to polyspermy?

9. Describe the cortical reaction.

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10. How is the fertilization envelope formed? 11. Why is the fertilization envelope considered a slow block to polyspermy?

12. Sperm binding activates a signal transduction pathway in which calcium ions are released from the endoplasmic reticulum. What are two outcomes of the elevated calcium ion level?

13. Now that you have studied sea urchin fertilization in some detail, study the section Fertilization in Mammals and make a list of what you consider the essential differences. You should have at least three differences.

14. The early mitotic divisions of the zygote to form a ball of cells are called cleavages. What is unique about cleavage?

15. How do the early cleavages set the stage for subsequent developmental events?

16. On the figure below, label and describe each of the following: fertilization envelope, zygote, blastomere,

blastula, and blastocoel.

17. Distinguish between the animal and vegetal pole.

18. This concept uses some anatomical terms that you need to know. Label the following parts on this diagram: anterior, posterior, dorsal, and ventral.

19. The point of the sperm nucleus entry will result in the formation of a gray crescent. How does this gray crescent serve as a marker?

20. The first cleavage will bisect the gray crescent. What axes are now established? Label the axes on the

figure. Also label the animal pole, vegetal pole, first cleavage, and gray crescent.

21. The amount of yolk found in an egg will affect cleavages. What is holoblastic cleavage? 3

22. What animals show holoblastic cleavage?

23. What is meroblastic cleavage? What animals show this type of cleavage?

24. The early cleavages are followed by gastrulation. Visualize punching in a partially inflated ball with your fist. This would result in a layer of the ball being pushed to the inside. In essence, this is what occurs in gastrulation. These layers establish the future embryonic germ layers. So remember this: gastrulation establishes the germ layers. What are the three germ layers of the embryo?

25. You should know at least two derivatives of each germ layer. Refer to Figure 47.14 in your text, and

select three tissues to learn from each layer. Use this chart to help organize your learning.

Ectoderm Mesoderm Endoderm

26. Going back to the pushed-in ball analogy, the area that is pushed in (invaginates, to the embryologist)

will form a tube called the archenteron. The archenteron forms the digestive tube, with an opening at each end, the mouth and the anus. Since the hollow ball that was pushed in was the blastula, the opening where the invagination occurs is called the blastopore. We want you to make a series of simple sketches below. Show a hollow ball (the blastula), then show it punched in as the archenteron forms, and then show the embryo with a completed digestive tube.

27. On the figures you drew above, label the blastula, gastrula, archenteron, blastopore, ectoderm, endoderm, blastocoel, digestive tube, mouth, and anus.

28. Let’s look back at the frog embryo. The figure on the left shows the gray crescent, which forms opposite

the point of sperm entry. Now look at the figure on the right. You will see that invagination occurs at the gray crescent. A crease forms where invagination occurs. The upper part of the crease is called the dorsal lip of the blastopore.

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29. On the sketches above, label the gray crescent, dorsal lip of blastopore, blastocoel, archenteron, blastopore, ectoderm, endoderm, and mesoderm. The sketch on the right shows gastrulation. Note that this process establishes the three germ layers. **** This is important to know! ****

30. So now, the embryo has three germ layers. Gastrulation is followed by organogenesis. Let’s look at the

formation of the neural tube in the sketch at right. The process by which this dorsal hollow nerve chord is formed is called neurulation, and the embryo stage is sometimes referred to as a neurula. Which germ layer drops down and folds to form the neural tube?

31. An important chordate characteristic is the notochord. What is a notochord? From which germ layer does it develop?

32. The development of the shelled egg was an important adaptation to allow the movement of animals

onto dry land. Which animal groups have shelled eggs?

33. Use this sketch of a chicken egg to name and give the function of the four extraembryonic membranes seen in amniotes.

34. Let us return to development in mammals. What is the mammalian version of a blastula? 35. Label the blastocyst below to show the blastocoel, inner cell mass, and trophoblast.

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36. The cells of the inner cell mass will form the embryo. What is the role of the cells of the trophoblast?

37. What is the function of the amnion?

38. Which extraembryonic membrane

a. cushions the embryo?

b. is involved in gas exchange?

c. serves as a disposal sac for embryonic wastes?

Concept 47.2 Morphogenesis in animals involves specific changes in cell shape, position, and adhesion

39. What is morphogenesis? (Reread the overview if you have forgotten.)

40. As stated in the concept heading, what are three things involved in morphogenesis? Concept 47.3 The developmental fate of cells depends on their history and on inductive signals

41. Although all cells in an organism have the same genome, explain two ways in which gene expression is altered during development.

42. What does it mean to say that a cell is totipotent?

43. Explain why two normal embryos result when the two blastomeres on the left are separated, but not when the two blastomeres on the right are separated.

44. Induction is an interaction among cells that influences their fate, usually by causing changes in gene expression. What did Speman and Mangold find to be the organizer that induced a series of events that result in the formation of a notochord and neural tube?

Testing Your Knowledge: Self-Quiz Answers Now you should be ready to test your knowledge. Place your answers here:

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1._________ 2._________ 3._________ 4._________ 5._________ 6._________ 7._________

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AP BIOLOGY 2019-20 READING GUIDE

Chapter 48: Neurons, Synapses, and Signaling Concept 48.1 Neuron organization and structure reflect function in information transfer

1. What is a neuron?

2. Neurons can be placed into three groups, based on their location and function.

Type of Neuron Function Transmit information from a sense receptor to the brain or spinal cord

Integrate information within brain or spinal cord; connect sensory and

motor neurons; located entirely within the CNS

Transmit information from the brain or spinal cord to a muscle or gland; Cause muscle contraction or gland secretion

3. Which division of the nervous system includes the brain and spinal cord?

4. This sketch shows two neurons. Label the following elements of this figure: cell body, dendrites, axon, synapse, presynaptic cell, postsynaptic cell, synaptic vesicles, synaptic terminal, and neurotransmitter.

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5. What is shown in the box above? What do the red spheres represent? Copyright © 2010 Pearson Education, Inc.

6. What is indicated by the red arrows in the main figure?

7. What are glial cells? Concept 48.2 Ion pumps and ion channels maintain the resting potential of a neuron In this section you will need to recall information about the structure and function of the plasma membrane. Ions are not able to diffuse freely through the membrane, because they are charged and so must pass through protein channels specific for each ion.

8. All cells have a membrane potential across their plasma membrane. What is the typical resting potential of a neuron?

9. On the sketch below, label the following: outside cell, inside cell. Show where the concentrations of Na+ and K+ are highest.

10. How are the concentration gradients of Na+ and K+ maintained? Concept 48.3 Action potentials are the signals conducted by axons

11. As you see in the figure above, in a resting neuron, the outside of the membrane is positively charged relative to the inside of the membrane. If positively charged ions flow out, the difference in charge between the two sides of the membrane becomes greater. What is the increase in the magnitude of the membrane potential called?

12. When a stimulus is applied, ion channels will open. If positively charged ions flow in, the membrane is said to depolarize. If depolarization causes the membrane potential to drop to a critical value, a wave of depolarization will follow. What is this critical value called?

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13. What is the wave of depolarization called?

14. Just like toppling dominoes in a row, either the threshold of depolarization will be reached and an action potential will be generated, or the threshold will not be reached and no wave will occur. What is this response to stimulus called?

15. Figure 48.10 contains almost all you need to know about nerve impulse transmission, so it is worth some careful study time. Let’s approach it in steps.

a. Label Na+, K+, and their respective ion channels.

b. Label the Resting state figure. Are the Na+ and K+ channels open, or closed?

c. Label Depolarization. What triggers depolarization? What channels open? What occurs if the

depolarization threshold is reached?

d. Label Stage 4 in the figure Repolarization. How is the charge on the membrane reestablished?

e. Label these regions of the graph: x- and y-axes, threshold, resting potential, depolarization, action potential, and repolarization.

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f. Let’s see if you really understand this concept. Draw in another line on the graph to show what the change in membrane potential would look like if a stimulus were applied that did not reach the depolarization threshold.

16. Here is a closer look at what is happening along the membrane as a wave of depolarization (an action potential) travels along the length of the axon. Label the key elements of the figure; and to the right, explain how the action potential is conducted.

17. What are the two types of glial cells that produce myelin sheaths?

18. How does a myelin sheath speed impulse transmission? Use the figure below, and include a discussion of saltatory conduction and nodes of Ranvier in your response.

19. In the disease multiple sclerosis, the myelin sheaths harden and deteriorate. How would this affect nervous system function?

Concept 48.4 Neurons communicate with other cells at synapses 11

20. When the wave of depolarization arrives at the synaptic terminal, calcium ion channels open. What

occurs to the synaptic vesicles as the Ca2+ level increases?

21. What is contained within the synaptic vesicles?

22. Label the figure below: synaptic vesicle, neurotransmitter, calcium ion channel, presynaptic membrane, postsynaptic membrane, and synapse.

23. Explain how an action potential is transmitted from one cell to another across a synapse by

summarizing what is shown above in six steps.

(1)

(2)

(3)

(4)

(5)

(6)

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24. There are many different types of neurotransmitters. Each neuron secretes only one type of neurotransmitter. Some neurotransmitters hyperpolarize the postsynaptic membrane. Are these excitatory or inhibitory neurotransmitters?

25. Define and explain summation.

26. A single postsynaptic neuron can be affected by neurotransmitter molecules released by many other neurons, some releasing excitatory and some releasing inhibitory neurotransmitters. What will determine whether an action potential is generated in the postsynaptic neuron?

27. Table 48.1 lists several of the major neurotransmitters. You are not expected to know their actions or secretion sites, but you should recognize that they are neurotransmitters! Go through the list that follows, and say each term aloud. Put a checkmark by any that you have heard mentioned before: acetylcholine, epinephrine, norepinephrine, dopamine, serotonin, GABA, glutamate, glycine, substance P, endorphins, and nitric oxide. That’s all for this question!

28. There is one neurotransmitter we want you to memorize. It is the most common neurotransmitter in

both vertebrates and invertebrates, and it is released by the neurons that synapse with muscle cells at the neuromuscular junction. If you look ahead to Chapter 50, Figure 50.29, you will see a synapse between a neuron and a muscle cell, resulting in depolarization of the muscle cell and its contraction. What is this very important neurotransmitter?

Testing Your Knowledge: Self-Quiz Answers Now you should be ready to test your knowledge. Place your answers here: 1._________ 2._________ 3._________ 4._________ 5._________ 6._________

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