Bio 20B Final Study Guide

Hormones and the Endocrine System

1. Hormone – define A hormone is a molecule that is produced in one part of the body but which acts on a target cell in another part of the body.

2. How are the endocrine and nervous systems related? How are their responses different? Endocrine system = all hormone secreting cells in the body. Endocrine is one of two communication systems in body. Nervous = wired, Endocrine = wireless

3. Give an example of a negative feedback loop that involves a hormone.

4. What kinds of molecules can act as hormones? Give an example of each. Proteins and peptides: ADH, oxytocin, insulinAmines (derived from amino acids): Thyroxine, epinephrine (adrenaline)Steroids: testosterone, estrogen, progesterone

5. Why does it matter whether a hormone is water soluble or lipid soluble? Which types of hormones are lipid soluble? Lipid soluble hormones can usually enter the cellAmines (derived from amino acids): Thyroxine, epinephrine (adrenaline) water or lipid solubleSteroids: testosterone, estrogen, progesterone lipid soluble

6. What are the roles of the hypothalamus and the pituitary glands in the endocrine system? Hypothalamus is the main integration center between the endocrine and nervous systems.- contains two sets of neurosecretory cells that secrete hormones that are either stored in or regulate the pituitary gland

Posterior Pituitary – extension of hypothalamus, stores and secretes ADH and oxytocin which are made in the hypothalamus- Composed of two distinct glands that are fused- Anterior and Posterior pituitary

7. What hormones do the hypothalamus and pituitary glands release? Anterior Pituitary- synthesizes and secretes at least 7 types of hormones: FSH Prolactin LH MSH TSH Endorphin ACTH GHPosterior Pituitary – extension of hypothalamus, stores and secretes ADH and oxytocin which are made in the hypothalamus

8. How are the anterior and posterior pituitary glands different in structure and function? How is their relationship with the hypothalamus different?Anterior Pituitary- Portal blood vessels connect hypothalamus to anterior pituitary, derived from gut tissue, makes & stores its own hormonesPosterior Pituitary – Neurons from hypothalamus extend to post. pituitary, derived from neural tissue, stores hormones made in hypothalamus

9. How is human growth factor different?

10. What causes pituitary giants, dwarfs?Abnormal production of GHPituitary giants result from excessive GH during childhood and acromegaly if high levels continue in adulthoodPituitary dwarfism results from insufficient GH secretion during childhood. Can be treated with synthetic GH if diagnosed before puberty. Stature is usually less than 4ft tall.

11. What hormones are involved in the flight or fight response?Catecholamines – synthesized from tyrosine in adrenal medulla (acute stress)Epinephrine (adrenaline)Norepinephrin (noradrenalin)

12. What does the adrenal gland do? The adrenal cortex—the outer part of the gland—produces hormones that are vital to life, such as cortisol (which helps regulate metabolism and helps your body respond to stress) and aldosterone (which helps control blood pressure).

13. Long term vs. short term stress response – compare and contrastMedulla CortexAcute stress (fight or flight)Epinephrine (adrenaline)

Chronic stress (longer term)Cortisol (steroid)

Increased HR, BP, BR, MRBreaks down glycogen for fast action ENShunt blood to vital areas (muscles)Connected to nervous system

Break down fats & proteins for long term ENImmune system suppressed

14. Which hormones are released for the short versus long term stress response and where are they released from? Short term: epinephrine (adrenaline) from medullaLong term: cortisol (steroid) from cortex

15. What is an endocrine disruptor? Endocrine disruptors are chemicals that may interfere with the body’s endocrine system and produce adverse developmental, reproductive, neurological, and immune effects in both humans and wildlife.

Locomotion

1. What is the role of the skeleton The skeleton provides structural support, protection, assisting in movement, storage of minerals, and production of blood cells.

2. Tendons, ligaments, define Tendons link bones to skeletal muscleLigaments link bones to bones or bones to cartilage

3. Hydrostatic, exoskeleton, endoskeleton – define, compare, contrast In organisms with hydrostatic skeletons, the muscles contract to change the shape of the coelom, which then produces movement due to the pressure of the fluid inside the fluid-filled cavity.Exoskeleton- a hard outer structure that provides both structure and protection to creatures such as insects, Crustacea, and NematodaEndoskeleton- the internal skeleton of an animal, which in vertebrates is comprised of bone and cartilage

4. Muscles – how do they interact with skeletal system Tendons link bones to skeletal muscleLigaments link bones to bones or bones to cartilageWhen muscles contract, the bones to which they are attached act as levers and cause various body parts to move.

5. Sliding filament theory – very important, should know the details here Steps1) Acetylcholine stimulates Ca2+ release from sarcoplasmic reticulum2) Ca2+ stimulates troponin to push tropomyosin off binding site

3) Myosin head binds to actin and changes its conformation/shape (power stroke)*Myosin bound to ATP when relaxed and ADP when contracted4) Ca2+ is pumped back into SR5) Another ATP binds to Myosin head and releases myosin from actin – return to resting state

6. What is rigor mortis?Muscle rigidity, usually temporary, following death.

7. Types of muscle fibers – define, compare, contrast (we may skip this is we run out of time.)

Animal Development

1. Cell potencyTerms that describe how far down the road of determination a cell has goneTotipotent – (all capable) – cell can differentiate into anything Pluripotent – (many capable) – cell can differentiate into most cell types but NOT new embryos Multipotent – (several capable) – cell can differentiate into several related cell types Unipotent– (one capable) – cell can produce only its same cell type

2. Stages of development (animals and plants) Determination – setting the fate of a cell; will cell become a heart cell? a brain cell?Differentiation – the process by which different cell types arise to perform different functions; how does it turn into a heart cell? A brain cell?Morphogenesis – (“ origin of form ”) how differentiated cells get organized spatiallyGrowth – increase in body size, organ size, by cell division and/or cell enlargement

3. Differential gene expression The expression of different genes within different cell types. All cells have whole genome – but they express those genes differently.

4. Cytoplasmic segregationCytoplasmic segregation – unequal cytokinesis; some factor is unevenly distributed within the cytoplasm

o Can lead to differential gene expression: Cytoplasmic determinants such as proteins, mRNAs, transcription factors ---->Genes

o Results in polarity: animal pole, vegetal pole

5. Induction Induction – Cell to cell communication; a factor is made and transported to induce other cells to differentiate

6. Morphogens & French Flag Model Morphogen- 1) Must directly target cells rather than triggering a secondary signal 2) Different concentrations of signal must cause different effects

7. Sonic Hedgehog function Morphogen = Sonic Hedgehog (Shh)Morphogen secreted from zone of polarizing activityThe thumb forms when Shh is absent. The pinky forms when there is a lot of Shh.

8. Maternal effect genes, segmentation genes, hox genes - temporal order, what they do Maternal Effects Genes anterior posterior (and dorsal ventral) axis ‐Segmentation Genes – boundaries and polarity of each segment Hox Genes – which organ will be made at given location, determine identity of segmentsThe products of these genes (ex: mRNA, proteins) set up morphogen gradients which lead to differential gene expression

9. Bicoid, Nanos, hunchback function in detail 1) Bicoid & nanos mRNA diffuse into future anterior end of egg2) Bicoid translated into protein– sets up gradient from anterior to posterior3) Nanos mRNA transported to posterior end---> protein4) Hunchback mRNA starts off evenly distributed but nanos inhibits translation of hunchback while bicoid increases translation = concentration gradient5) Hunchback is made at anterior end & triggers development of anterior structures (head)

10. Stem cells - embryonic and pluripotent Stem Cells – rapidly dividing undifferentiated cells that can differentiate into diverse cell types 1) Embryonic Stem Cells (ESCs) – Group of cells in the blastocyst of mice and humans; can give rise to most cell types but not new organism 2) Induced Pluripotent Stem Cells (iPS) – induce adult skin cells back to an undifferentiated state; can make many cell types

11. How are stem cells made and how are they used, what are advantages of induced pluripotent?Bone marrow– site of production of blood & immune cells

o Hematopoietic Stem Cells – Blood Cells o Mesenchymal Stem Cells – bone, connective, muscle cells

In Humans: Cancer Treatment: Stem Cell transplantIn animals: arthritis in dogs, diabetes, Parkinson’s like disease, sickle cell anemia‐Adult Pluripotent Stem Cells advantages:1) Avoid controversy of ESCs 2) Avoid Immune system problems from introducing “non self” tissue into another individual‐

12. What is a model organism?A model organism is a species that has been widely studied, usually because it is easy to maintain and breed in a laboratory setting and has particular experimental advantages.

Plant Introduction

1. Why are plants interesting?They can make their own food through photosynthesis.

2. Why are plants important to humans? Plants provide food and oxygen for humans and most living organisms. They also take in CO2 to help reduce green house gases and global warming.

3. Why is phylogeny important?

Plants are very diverse so we use a phylogeny to organize them which allows us to compare their physiology and ecology.

4. How is plant diversity organized? Non-vascular plants vs. vascular plantsVascular structures were key to allowing plants to colonize terrestrial environments= the circulatory system of the plant

5. Structure of plant cell, Fig 5.7, also in notes

6. 3 Cell types(characteristics, examples) Parenchyma Collenchyma SclerenchymaMajority of cells in plant• Totipotent• Metabolically active• Important for storage,

Alive when mature• Cell walls are thickened at corners• Contain a lot of pectin (jams &

Thickened secondary cell walls• Major function = Support• Undergo apoptosis after secondary cell wall formed

photosynthesis• Large vacuoles• Thin cell walls• Most of fruit is made of these• Most of a leaf is made of these

jelly)• Found at bases of leaves & non woody stems‐• “Sway in the wind” flexiblesupport• Celery “strings” are mostlycollenchyma

• Mainly perform functions after dead• Contain lignin• Two Types• Fibers• Sclereids

7. 3 tissues, how they are manifested in different organs 1) Dermal – forms the outer covering of the plant (epidermis) and usually consists of a single cell layer2) Vascular – the plumbing; transports water & nutrients from site of production/intake to where needed

o Xylem – Transports water & mineral ions from roots to rest of planto Phloem – transport of carbohydrates (sugars) from sites of production to sites of use or storage

3) Ground – forms most of the plant body; function in storage support, photosynthesis

8. Structure of root, stem, and leaf

9. Basic plant body plan (nodes, internodes, apical & axillary buds, etc.)

10. Cell division and development: meristems, woody stems of trees Meristems- cells that remain totipotent and clustered in specific regions Apical meristem- primary growthLateral meristem- secondary growth Root meristem- primary growth

11. Monocots vs. Eudicots