Exam 1 Study Guide

Question 1

What are the components of the mammalian cell? Describe the primary functions and attributes of those components

Answer 1

Plasma membrane: separates cells from its environment and controls passage of substances, made of a phospholipid bilayer
Nucleus: Houses genetic material, nuclear envelope (membrane) is continuous with ER membrane, chromatin condenses into chromosomes at division, nucleolus produces ribosomal subunits and rRNA.
Mitochondria: has a smooth outer membrane, highly folded inner membrane (electron transport enzymes, high proton concentration between the outer and inner membrane)
Ribosomes: the organelle responsible for making proteins from mRNA
Rough ER: the rough endoplasmic reticulum houses the ribosomes and is where protein synthesis occurs (shares a membrane with the nucleus)
Smooth ER: where synthesis of lipids & steroids occurs
Golgi apparatus: where modification of some proteins occurs
Lysosomes: essentially the digestive system of the cell, digesting waste and breaking down macromolecules
Centrosome: organizing microtubules and providing a structure to the cell

Question 2

Describe the different methods by which molecules can permeate the plasma membrane

Answer 2

simple diffusion: passive transportation through the plasma membrane, molecules easily pass through
facilitated diffusion: passive transportation that is facilitated by energy
exocytosis/endocytosis: more active process where molecules exit/enter through vesicles
active transport: active process where ATP is used to bring molecules into the cell via a carrier

Question 3

What is the primary energy currency of the cell? By what process(es) is this molecule generated?

Answer 3

the primary energy currency of the cell is ATP, it is generated via glycolysis, the krebs cycles, the electron transport chain, and chemosmosis

Question 4

Describe the steps involved with glycolysis. Understand and describe the start and end products, what other products may be generated, and where in the cells this occurs

Answer 4

glycolysis occurs in the cytoplasm and during the process everything happens twice. it begins with glucose and ends with pyruvate. the first four stages require energy while the rest are energy releasing

Question 5

Understand the reaction that converts pyruvic acid into acetyl CoA and where this occurs in the cell

Answer 5

this reaction occurs prior to entering the krebs cycle inside the mitochondria. CO2 is exhaled and coenzyme A enters near the end creating acetyl CoA

Question 6

Describe the steps involved with the TCA cycle. Understand and describe the start and end products, what other products may be generated, and where in the cells this occurs

Answer 6

fatty acids (& proteins) enter as Acetyl CoA and generates 3 CO2, 2 NADH, 1 IADH, and 1 ATP. it happens twice per glucose and it occurs in the mitochondria. the first step converts pyruvic acid to CoASH and then condenses into citric acid then oxidizes into isocitric acid which turns into ketoglutaric acid which then turns into succingyl - CoA and then through regeneration it turns into fumaric acid.

Question 7

Describe the steps involved with the electron transport chain. Understand and describe the start and end products, what other products may be generated, and where in the cells this occurs

Answer 7

the electron transport chain occurs in the mitochondria. INADH turns into 2-5 ATP and FADH turns into 11-5 ATP

Question 8

What is produced during transcription? Understand how transcription factors can modulate the transcription process.

Answer 8

during transcription DNA is turned into mRNA. transcription factors are proteins that regulate transcriptions of genes. enhancer proteins bind stimulatory (activator) factors to activate certain genes and repressor proteins bind inhibitory (silencer) factors to inhibit certain genes. activators stimulate transcription in 3 ways: recruit transcriptional machinery, chromatin remodeling, and stimulate RNA polymerase. repressors act by competition, quenching, or active repression

Question 9

Describe (in broad terms) the steps involved with translation

Answer 9

tRNA binds to matching codon, the polypeptide is linked to the new amino acid, mRNA is shifted forward exposing a new codon, then it begins again

Question 10

What are post-transitional modifications? Why would proteins be modified?

Answer 10

they occur on proteins after translation and regulates the protein compartmentalization/trafficking and activity

Question 11

Describe the process of translation and export for secreted proteins (i.e. the secretory pathway). How does this differ from production of intracellular proteins and membrane proteins?

Answer 11

proteins that will be secreted outside enter the ER through a translocon via the secretory pathway. protein synthesis begins, then is inhibited, and then resumes. the signal sequence is then cleaved and protein synthesis continues to completion and the ribosome then dissociates leaving a completed protein within the cell.

Question 12

Describe the different mechanisms by which cells communicate with one another

Answer 12

autocrine: chemicals that interact with the cell that secreted it
paracrine: chemicals that communicate with neighboring cells
juxtacrine: cell’s receptors touch and communicate this way
endocrine: hormones secreted via the adrenal gland communicate with the cell

Question 13

What are the primary categories of hormone? Understand what this means regarding what they are composed of and how they would be made

Answer 13

peptide hormones: chains of amino acids and proteins
amino acids & their derivatives (amines)
lipid derived hormones: steroids (derived from cholesterol) eicosanoids (derived from arachidonic acid)
misc: several unique factors

Question 14

What is the role of a ligand in a signaling cascade?

Answer 14

they act as a signaling molecule that initiates the process by binding to a specific receptor, this binding triggers a cascade of events within the cell, leading to a cellular response

Question 15

What is the role of an effector in a signaling cascade?

Answer 15

an effector acts as the ultimate target protein that carries out the cellular response to the initial signal. it’s the molecule that directly changes the cell’s behavior, often by influencing processes like gene expression or cell activity

Question 16

What are the different categories of endocrine receptors?

Answer 16

ligand-gated channels, catalytic receptors, G-protein coupled receptors, nuclear/cytosolic receptors, receptors that undergo cleavage

Question 17

Identify the basic steps in any signal transduction pathway

Answer 17

1. recognition of signal by receptor
2. transduction of extracellular message to intracellular signal (second messenger, conformational change in receptor)
3. second messenger’s signal transmitted to effector (may have several, amplification)
4. effector modulation (kinases, phosphatases, etc)
5. cellular response
6. termination

Question 18

Describe the feature of ligand gated receptors. Understand the steps of signal transduction for this receptor category.

Answer 18

they are integral membrane proteins. the binding of a receptor opens a channel. communication using this happens between electrically excitable cells

Question 19

Describe the features of a catalytic receptor. Understand the steps of signal transduction for one type of catalytic receptor (RTK). Do all catalytic receptors follow the same excretory pathway?

Answer 19

they are integral membrane proteins and are enzymes (or part of enzyme complexes).

Question 20

What is the function of kinases? Phosphatases?

Answer 20

kinases transfer a phosphate group to a protein. phosphatases removes a phosphate group from a protein

Question 21

Understand the structure and features of a G-protein coupled receptor. Be able to describe
the steps involved with basic GPCR signal transduction.

Answer 21

messenger binding activates a G protein to initiate response (GTP-binding proteins, alpha, beta, and gamma subunits)

Question 22

GPCR can activate many different downstream effects. Be able to describe the steps
involved with the adenylate cyclase and phospholipase C pathways

Answer 22

adenylate cyclase: G proteins are activated, which activate adenylate cyclase which causes a downstream effect and generates cAMP molecules which then activate protein kinase A. protein kinase A phosphorylates hundreds of proteins
phospholipase C: GPCR can help multiply proteins similarly to adenylate cyclase

Question 23

Be able to differentiate how signal transduction differs in stimulatory and inhibitory G-proteins

Answer 23

stimulatory G-proteins activate amplifier enzymes. inhibitory G-proteins inhibit amplifier enzymes

Question 24

Understand the structure and features of a nuclear receptor. What features must a signaling molecule have to act on a nuclear receptor. Be able to describe the steps involved with this
basic signal transduction.

Answer 24

nuclear receptors are proteins in cytosol or nucleus, they are ligand activated transcription factors. signal transduction of a nuclear receptor begins when a steroid hormone meets a receptor protein on the nucleus. this then moves to the hormone-receptor complex within the nucleus which translates DNA into mRNA which exits the nucleus as a new protein

Question 25

What compound are steroid hormones synthesized from? Identify some examples of steroid hormones

Answer 25

steroid hormones are all synthesized from cholesterol. some examples of this are progesterone, cortisol, testosterone, and estradiol

Question 26

How are some ways the endocrine system controls and regulates communication? Understand the difference between positive and negative feedback.

Answer 26

simple feedback loop: sensor -(hormone)> target 1 -(other hormone or metabolite)> target 2. in this the other hormone/metabolite will send a negative feedback loop to the original sensor hierarchical control: cerebral cortex -> hypothalamus -(CRH)> anterior pituitary -(ACTH)> adrenal cortex -(cortisol)> target tissue. in this loop the CRH and ACTH send positive feedback to the anterior pituitary & adrenal cortex. cortisol sends back a negative signal to ACTH and CRH.

Question 27

Describe how the hypothalamus and pituitary gland interact to control body system. This includes the basic structure of the hypophyseal portal system, the basic structure of the anterior and posterior pituitary, and how signals are sent to the pituitary from the hypothalamus.

Answer 27

hormones that are released from the hypothalamus cause hormones to be released from the pituitary. hypophyseal portal system: a specialized network of blood vessels that connect the hypothalamus to the anterior pituitary gland, facilitating communication between the two anterior pituitary: located on the anterior lobe of the pituitary gland, different cells produce and secrete different hormones posterior pituitary: located on the posterior lobe of the pituitary gland, signals sent from the hypothalamus stimulate release of hormones from this lobe

Question 28

How do the anterior and posterior pituitary differ in terms of hormone production and storage? What are some hormones produced by each?

Answer 28

the anterior pituitary contains different cells that produce different hormones directly, the posterior pituitary receives signals from the hypothalamus and releases hormones this way. anterior pituitary produces GH, TSH, ACTH, FSH, LH, PRL. the posterior pituitary produces AVP and oxytocin

Question 29

Understand the different cells that comprise the anterior pituitary and hormones produced by each.

Answer 29

somatotrophs: growth hormone (somatotropin) lactotrophs: produce prolactin gonadotrophs: follicle stimulating hormone, luteinizing hormone thryotrophs: thyroid stimulating hormone (TSH) corticotrophs: adrenocorticotropic hormone (ACTH), beta-lipotropin

Question 30

What stimulates/inhibits production and release of growth hormone?

Answer 30

somatotrophs stimulate and inhibits production/release of GH

Question 31

Where growth hormone is produced and the mechanism by which it is released?

Answer 31

it is produced in the anterior pituitary and is released by the release of GHRH from the hypothalamus

Question 32

What growth hormone’s primary organ target is, what happens in this organ upon growth hormone binding?

Answer 32

the growth hormone's primary organ target is the liver & other tissues. upon binding there are IGFs that happen (skeletal effects & extraskeletal effects)

Question 33

Describe the process of production and release of IGF-1

Answer 33

it is mainly produced by the liver after the liver receives stimulatory GH hormones

Question 34

Describe how IGF-1 is transported

Answer 34

it is bound to IGFs

Question 35

Describe the BASIC mechanism by which it causes its effects in the target cell (what type of receptor it binds to and the ultimate outcome)

Answer 35

it causes effects by binding to RTK

Question 36

Describe the feedback mechanisms responsible for regulating this pathway

Answer 36

GH receives either GHRH or GHIH which is stimulatory or inhibitory

Question 37

What are the direct effects of growth hormone? Indirect effects? Is the growth hormone pathway the only way to control growth?

Answer 37

skeletal effects: increased cartilage formation & skeletal growth extraskeletal effects: increased protein synthesis, and cell growth and proliferation fat: increased lipolysis carbohydrate metabolism: increased blood sugar and other anti-insulin effects

Question 38

What signals initiate this response (stress response)

Answer 38

it can be many different stressors such as predation or adverse weather (external) or internal like illness or medical procedures

Question 39

What causes the anterior pituitary to produce and release ACTH?

Answer 39

the brain sends ACh to the hypothalamus to let the body know that it is feeling a stressor, the hypothalamus sends CRH to the anterior pituitary where it then releases ACTH to the adrenal cortex to release glucocorticoids

Question 40

What is the signaling mechanism for production and release of ACTH?

Answer 40

CRH or hypothalamic corticotropin releasing hormone

Question 41

Where ACTH causes its effects?

Answer 41

primarily targets the adrenal glands, specifically the adrenal cortex

Question 42

The signaling mechanism that occurs after ACTH binds its receptor?

Answer 42

after binding to its receptor, ACTH initiates a signaling cascade primarily involving the cAMP/PKA pathway

Question 43

How does cortisol act on its target cell

Answer 43

activates anti-stress pathways and anti-inflammatory pathways

Question 44

Describe feedback associated with regulating this pathway

Answer 44

epinephrine will send positive feedback to the anterior pituitary while cortisol will send negative feedback to the anterior pituitary, hypothalamus, and brain. ACTH will also send negative feedback to the hypothalamus

Question 45

Understand the basic structure of the adrenal gland and which regions produce/store each type of hormone.

Answer 45

the adrenal gland is a pyramid shaped organ above the kidney. it's two glands in one: the adrenal medulla (nervous tissue) and adrenal cortex (layers of glandular tissue that secrete corticosteroids). there are three secretion areas of the cortex, the zona glomerulosa (mineralcorticoids), zonal fasciculata (glucocorticoids), and zona reticularis (gonadorcorticoids). the adrenal medulla produces epinephrine and norepinephrine

Question 46

What is the ultimate outcome of the stress response during short term stress? Long term stress?

Answer 46

short term: greater energy availability (fat breakdown and proteolysis for energy), greater pain tolerance, better memory function, temporary immune boost, blood pressure, and regulates insulin long term: anxiety, depression, headaches, weakened immune system, heart disease, higher blood pressure, digestive issues, nerve problems, and high blood sugar

Question 47

Describe communication between the hypothalamus and the pituitary

Answer 47

they communicate through a combination of hormone release and nerve impulses primarily via the pituitary stalk

Question 48

Describe the signaling mechanisms in the thyrotroph that result in the production and release of TSH

Answer 48

the hypothalamus sends SS and TRH signals to the pituitary to release TSH

Question 49

Where does TSH cause its effects?

Answer 49

TSH causes its effects within the thyroid, which produces T3 and T4

Question 50

How are thyroid hormones produced

Answer 50

1. thyroglobulin is synthesized and discharged into the lumen 2a. trapping (active uptake of iodide) 2b. oxidation 3. iodine enters follicle lumen where it is attached to tyrosine in colloid forming DIT and MIT 4. iodinated tyrosines are linked together to form T3 and T4 5. thyroglobulin colloid is endocytosed and combined with a lysosome 6. lysosomal enzymes cleave T4 and T3 from thryoglobulin colloid and hormones diffuse from follicle cells into bloodstream

Question 51

Describe the signaling mechanism by which TSH causes thyroid hormone synthesis and release

Answer 51

1. TSH binding and receptor activation 2. G-protein signaling pathway 3. effects on thyroid hormone synthesis and release 4. negative feedback regulation

Question 52

Describe the mechanism by which thyroid hormones cause their effects in target cells. Which of the thyroid hormones is most metabolically active?

Answer 52

T3 diffuses into the cell and binds to a cytoplasmic receptor inside/outside of the nucleus. it goes to the nuclear receptor then hormone receptor complex. DNA activates a hormone response element on the receptor which translates it into mRNA. mRNA then is translated into a enzyme/protein by ribosomes outside of the nucleus.

Question 53

Describe feedback mechanisms associated with this pathway

Answer 53

T3 and T4 send negative feedback to the pituitary as well as the hypothalamus.

Question 54

What are the biological effects of thyroid hormone?

Answer 54

glucose oxidation, increasing metabolic rate, heat production, has a role in: maintaining blood pressure, regulating tissue growth, developing skeletal and nervous systems, and maturation and reproductive capabilities

Question 55

What are the 6 levels of body organization? Be able to describe them and place them in order of complexity.

Answer 55

(most to least complex) 1. chemicals 2. cell 3. tissues 4. organs 5. organ systems 6. organism

Question 56

Describe the different body systems. You will not need to list all body systems from memory, but do need to have an understanding of what each system does.

Answer 56

integumentary: external covering of the body - protection, moisture retention, sensory information skeletal: support, protection, movement, blood cell formation and mineral storage muscular: movement, posture, heat generation nervous: coordinates animals interactions with internal and external environment endocrine: hormone production to maintain homeostasis cardiovascular: blood vessels and heart, transport nutrients and waste lymphatic: return excess fluid to blood, immunity respiratory system: gas exchange to provide body oxygen digestive: nutrient acquisition, immune function urinary: elimination of waste, maintain fluid balance reproductive: production of offspring

Question 57

What are the 4 primary tissue types and where is their primary function? (particularly epithelial and connective)

Answer 57

epithelium: covers a surface, protection, glandular activity connective: provides support, storage, protection muscle: skeletal, smooth, cardiac nervous

Question 58

What is an epithelium? How are different epithelia named? You should be able to describe the structure of an epithelia from its name and vice versa

Answer 58

an epithelium covers the surface of body and body cavities. they are named for the number of layers, shape of cells, and processes. simple squamous has a "fried egg" shape.

Question 59

What is the function of glands? What are the 2 primary categories of gland and how do they differ?

Answer 59

they secrete or excrete cells. the two types of glands are unicellular or multicellular. unicellular glands are individual secretory cells interspersed with other epithelial cells. multicellular glands are many secretory cells folded to form a more complex gland shape

Question 60

Describe the 3 primary ways we can join epithelial cells together.

Answer 60

occluding/tight junction: interlocking junctional proteins anchoring junctions: adhering junctions with protein filaments or desmosomes with plaque, linker proteins, and intermediate filaments communicating junctions: gap junctions with channels between cells

Question 61

What is the defining feature of connective tissue? What are some examples of connective tissue?

Answer 61

they are responsible for supporting and holding all organs and tissues of body in place, cells embedded in extracellular matrix (ECM) - noncellular material surrounding cells. some examples are loose connective tissue, dense connective tissue, adipose tissue, cartilage, bone, and blood

Question 62

What is the integumentary system?

Answer 62

it is comprised of skins and its derivatives (sweat & oil glands), hair (wool, fur), and nails (claws, hooves).

Question 63

What are some functions of the integumentary system?

Answer 63

physical protection, sensory info, secretion, storage, body temp regulation, and communcation

Question 64

What are the 3 primary layers of skin? Be able to describe them from most superficial to most deep.

Answer 64

1. epidermis 2. dermis 3. hypodermis

Question 65

Understand the structure of the epidermis, the role of keratin, and how epidermal cells change as they migrate towards the surface of the body.

Answer 65

it is the thin outermost layer (stratified squamous epithelium) base cells divide and keratinize as they push upward. keratin is a protein deposited in epidermal cells that provides protection and water resistance. there are four layers of the epidermis: 1. stratum basale - single layer of dividing cells; melanocytes may be present 2. stratum granulosum - keratinization begins 3. stratum lucidum - cells lose nuclei 4. stratum corneum - outermost layer, cells are dead, flattened and fully keratinized

Question 66

Describe the structure and function of the dermis. Understand how hair follicles and glands that lie within this region are formed from epidermal cells

Answer 66

the layer of skin under the epidermis. it is a connective tissue with collagen and elastin, has the blood supply and nerves. here are where hair follicles are found, glands lie within this layer but are formed from epidermal cells

Question 67

Describe the structure and function of the hypodermis.

Answer 67

it is a layer of loose connective tissue and fat underneath the skin made of elastic fibers

Question 68

Describe the primary types of glands found in the skin and their primary role.

Answer 68

sebaceous glands: open into the base of hair follicles and excrete oily substance called sebum that as an antiseptic quality that waterproofs coat and moisturizes skin (some modified versions may produce pheromones) sweat glands: excrete water with salts to cool animal off (only active on nose and footpads of dogs and cats)

Question 69

What is the composition of hair? Describe the shaft and root of a hair.

Answer 69

the shaft is the visible part of the hair and the root is the part that lies within the follicle

Question 70

Describe hair growth, shedding, and factors that influence shedding.

Answer 70

hair growth is cyclical, hair will shed and new hair grows in its place. shedding is influenced by temperature and day length

Question 71

Describe the 3 primary types of hair discussed in class, their primary functions, and how they differ.

Answer 71

guard hairs: thick, long, stiff hairs that form protective outer coat wool hairs: soft undercoat, thinner, short hairs (several can originate from one follicle, thickness (or presence) varies between animals) tactile hairs: whiskers (thicker than guard hairs, follicle surrounded by nerve endings that respond to touch or movement)

Question 72

Describe the role of the arrector pili muscle in piloerection – for both communication and temperature response

Answer 72

contraction of the arrector pili muscle associated with the hair follicle that raises hair from the resting position. it is stimulated by cold temperature or a response to a threat

Question 73

Understand the basic composition of nails, horns, claws and hooves

Answer 73

nails: hard plates of tightly packed keratinized cells (3 parts: body, free edge, and nail root, grows at nail matrix within root and pushes out as it grows) claws: similar in structure to nails (cats have digital flexor muscle to extended and retract claws) horns: tough outer covering of epidermal tissue, highly keratinized and originate from a germinal center overlying skull hooves: outer wall is an insensitive keratinized epithelium, more similar to extension of skin than nails/claws

Question 74

What is the basic component of a feather? Describe parts discussed in class: shaft, vane, etc.

Answer 74

shaft is originally filled with capillaries but becomes hollow as feather matures. the vane has barbs and barbules that hook together to keep feather flat and wind resistant.

Question 75

What is bone and what are some functions of bone?

Answer 75

a type of connective tissue that supports framework of the body, protects organs, stores calcium, and performs hematopoiesis

Question 76

What is the constitutive cell of bone? What makes up its ECM?

Answer 76

osteocytes are the constitutive cell in the bone. the extracellular matrix is made of protein (osteonectin), collagen fibers, and calcium phosphate crystals

Question 77

Understand the basic structure of bone

Answer 77

channels run through the matrix to carry blood vessels and nerves and are surrounded by concentric cylinders of matrix and trapped osteocytes

Question 78

Describe bone classification by type, shape, and specialization

Answer 78

compact bone: more densely packed bone matrix spongy bone: meshwork of bony "struts" with red bone marrow in between long bone: bones of limbs, have shaft with medullary cavity that contains bone marrow short bone: outer layer of compact bone with core of spongey bone, no cavity flat bone: outer layer of compact bone with core of spongey bone, no cavity irregular bone: similar to short bones with less uniform shape sesamoid: seed shaped bones found within tendon (patella) pneumatic: contain air-filled spaces called sinuses that help reduce weigh t(some bones of skull) splanchnic: formed within a soft organ, not attached to skeleton (os penis)

Question 79

Understand the importance of bone marrow, be able to provide an example of a compound generated by bone marrow.

Answer 79

bone marrow is important because it houses hematopoietic stem cells which make blood through hematopoiesis. myeloid progenitor cells are produced here

Question 80

What cell types assist with formation and remodeling of bone tissue? What is the role of each?

Answer 80

ossification is the formation or remodeling of bone. osteoblasts and osteoclasts are the cells that aid in oddification. osteoblasts form new bone and build it. osteoclasts destroy old bone

Question 81

Understand the steps to ossification in developing bone.

Answer 81

1. cartilage model develops (embryo) 2. cartilage is replaced as osteoblasts lay down new bone (starts in shaft of bone and works toward ends) 3. ossification starts at ends of bone 4. osteoclasts remove bone from center to form marrow cavity 5. narrow band of cartilage persists between shaft and bone ends - growth plate/epiphyseal plates (growth plates closed when this is replaced by bone)

Question 82

Describe some special adaptations of bird bones.

Answer 82

they are much thinner and many long bones are hollow, there is a greater proportion of pneumatic bones, some bones are fused for a fewer number of joints