2 Flashcards
Identity, 2 subtypes of identity
How we view ourselves
- personal identity
-
social identity
- usually what is being discussed
Identity can be
negotiated and contested
- This allows people to apply identities/labels to people who may disagree
Forms of Identity
- Age
- Race: based on physical characteristics
- Ethnicity: refers to ones cultural background
- Nationality: political and legal concept independent of race and ethnicity
Gender Identity:
Sexual orientation
- sexual vs. romantic orientation
how people perceive themselves relative to social categories masculinity and femininity
-
Gender is a social construct
- cisgender: gender matches sex
- transgender: gender distinct from sex
- Sex is a biological category
Sexual orientation: who people are attracted to as sexual partners
- homosexual: same sex
- heterosexual: opposite sex
- bisexual: both
- pansexual: all sexes
Sexual vs. romantic orientation: asymmetry between who someone wants to be a sexual partner and a romantic partner
Categories of Identity
Socioeconomic class
Religion
- the relative importance, or salience, of these categories differ among people and societies
Development of identity
Social Factors
Input about who they are themselves and how they relate to others
Explicit input: someone telling them something
Implicit input: observed behaviors
Socialization shapes gender norms, roles, and identity
Theories on Identity: Freud’s Pyschosexual Perspective
Conflicts or complexes acquired in various developmental stages can impact someone’s identity
Theories on Identity: Kohlberg’s Theory of Moral Development
6 stages
Morality in the light of social conventions can shape political identity and sense of self
Looking-Glass Self Concept
Our perceptions about how other people see us shapes how we see ourselves
- people send us explicit and implicit messages about how they perceive us
George Herbert Mead (1902)
Role Model
How children internalize and imitate examples set by adults in their surroundings
Role Playing (Role Taking)
Who?
George Herbert Mead (looking glass self)
Essential to inhabiting and understanding others perspectives
- child games help replicate social expectations regarding roles in society
- end point of this process is targeted toward the self
Impression Management
Impacts how others see us in specific social settings
Reference Groups
Groups we compare ourselves to (usually groups we belong to)
- reference groups and the act of comparing ourselves to them can shape our identities
Socialization
How people and institutions from society shape our acquisition of social norms and expectations
- acts as a mechanism for identity formation
Facets of the Self
Self-Concept (self-identity) and Self Schemas
Self Verification
How we perceive ourselves
- uses self schemas: organized, specific concepts about the self
- having a good sense of humor
Self schemas affect how we behave in accordance with self verification
- the desire for others to perceive us how we perceive ourselves
Self Identity
Like self concept but with greater emphasis on social identity
Locus of Control
Where we place responsibility for events/outcomes
Internal locus of control: seeing oneself as responsible for events
External locus of control: explaining events in terms of external forces
Self Efficacy
Preception of self as capable of acting effectively in a given setting
- high self efficacy associated with internal locus of control
Defined in narrow terms
self esteem- overall self worth
Self efficacy and self esteem don’t have to go together
Locus of control, self efficacy, and self esteem contribute to
Self identity/self concept
Culture
Elements of Culture
Common practices and shared understandings that bind us together in a society
Material culture vs symbolic culture
- material- personal possessions, consumer products, buildings, roads, etc.
- symbolic- non-tangible elements of culture
Symbolic Culture
Non-tangible elements of culture
Beliefs: general cultural consensus of how the world works
Values: how the world should be, how people should act, and what should be prioritized
- help create social norms and personal values
Rituals: cultural actions that have a script; ceremonies, holidays, personal routine
Symbols: cultural shorthand for ideas; unlike beliefs and values, symbols don’t imply you buy into a value, instead are negotiable based on personal perspectives
Language: the way a culture communicates; language doesn’t equal culture
- lanugage can capture culturally specific concepts, slang
Subcultures
- Groups of people within a larger culture
- Have additional cultural practices or practices at odds with the larger culture
Countercultures
Subcultures that are in opposition to the broader culture that surrounds them
- countercultures may not choose this term for themselves
Mass Media
Radio, television, and newspapers
- small number of radio stations, newpapers and TV channels could reach large majority of public
- helps shape popular cultures (pop cultures)
- of the people (population)
Emergence of the internet has decentralized pop culture
Culture and human evolution
Culture has been a major driver of human evolution
- genetic traits that help humans use tools skillfully and participate in process of passing down that knowledge will be favored evolutionarily
- tool/technology use impacts reproductive success and evolution
Cultures change over time and interact with each other
Culture Lag vs. Culture Shock
Culture Lag: when material culture changes faster than the nonmaterial culture can “catch up”
- ex. testing introduced, took time for norms about social texting
- Can be seen within one culture or between cultures
Culture Shock: Sense of unease when immersed in a new culture
- Feeling out of place navigating new social norms in an unfamiliar environment
- immigrants, anthropologists
Migration leads to…
Assimilation and Multiculturalism
Cultural diversity
Assimilation: integration into the predominant culture
- learning major language, adopting cultural norms
- affected by residential segregation and acceptance by society
Multiculturalism: preservation of original cultures within local communities
Cultural transmission and diffusion
Transmission: elements of a culture passed down from one generation to another
- rituals, myths, values, symbols
Diffusion: cultural elements passed from one culture to another
Carbohydrates are defined by their
Common structure
- Carbon chains hydrated with hydrogen and oxygen atoms
- Cm(H2O)n
Glucose is carbohydrate fuel source in most organisms; synthesized by plants/algae via photosynthesis and consumed by animals
Monosaccharides are
Sugar monomer, building blocks of complete carbohydrates
- many can be directly absorbed into bloodstream by small intestine and broken down for energy
Either an aldose and ketose
ex. Glucose
Usually colorless, water soluble, and sweet
Classification of monosaccharides
Classified by number of carbons in their skeleton; most are D-isomers
- triose- glyceraldehyde in glycolysis
- tetrose
-
pentose- ribose (nucleic acids, RNA)
- ribose 5-phosphate key component of pentose phosphate pathway
- **hexose- glucose, fructose, galactose
**Recognize structural differences (picture)
Glucose (hexose monosaccharide)
Most abundant monosaccharide on earth, major role in metabolism and syntheiszed by plants for polysaccharide cellulose (cell wall)
- In aqueous solution, exists primarily as pyranose (ring structure)
Aldose: glucose contains aldehyde functional group
In Fischer Projection, hydroxyl on carbon 3 points opposite direction as other hydroxyl groups
Fructose (hexose monosaccharide)
Hexose with 5 membered ring
- honey, fruits, root vegetables, synthetic food additive
- high fructose corn syrup linked to obesity, diabetes
Also found in disaccharide sucrose with glucose
Galactose (hexoe monosaccharide)
Aldose that can be easily converted to glucose through metabolic pathway
Avocados, beets, honey
Milk and cheese as component of disaccharide lactose
Monosaccharides are linked by
Bonds are formed by ___ reactions
Glycosidic bonds- formed by dehydration reactions, liberating H2O molecule
- transforms hemiacetal/hemiketal group into a acetal /ketal group
What enzyme creates glycosidic bonds, what enzyme breaks them down
Glycosyltransferases create new glycosidic bonds
- glycogen synthase in the liver
Glycosidase enzyme breaks glycosidic bonds via acid-catalyzed hydrolysis reaction
- Beta-galactosidase hydrolyzes glycosidic bond of lactose to liberate glucose and galactose
**Always involve anomeric carbon of at least one sugar
Anomers
5 and 6 carbon carbohydrates have an anomeric carbon
Anomers: carbohydrate isomers that differ in their orientation of their substituents (hydroxyl group) at anomeric carbon
- ***In linear form, only carbon with double bond to oxygen
Due to carbonyl, anomeric carbon is electrophile, site of nucleophilic attack for cyclization
- Hydroxyl groups far down carbon chain serve as nucleophiles
- closer ones to anomeric carbon would cause too much steric strain
**Unlike diastereomers and enantiomers, anomers interconvert at equilibrium
Each sugar has two anomer forms
Alpha and beta monomer depending on how ring system closes during cyclization
- can completely change the properties of the sugar
Disaccharides
3 to know
Two monosaccharides joined by glycosidic bonds; physical and chemical properties depend on sugar components and where they’re linked
- crystalline, soluble in water, sweet
Sucrose- table sugar; composed of glucose and fructose
Lactose- dairy productsl galactose and glucose
- majority of worlds adults lack lactase, lactose intolerant
- all mammals express lactase in childhood for breast milk but expression turns off
- northern european and african heritages continue expression
Maltose- two glucose monomers; less sweet than sucrose
Capsule of pathogenic bacterias
Thick layer of carbohydrates that avoids detection by hosts immune system because it masks antigenic proteins on the cell surface
Polysaccharides
Use in vaccines
Long chains of carbohydrate monomers linked together
- vaccines contain inert polysaccharide capsules (mask antigenic proteins of bacteria) so immune system can recognize them
Starches
Polymers of glucose that plants use to store energy; also pack vegetables and grain with carbs
- One of the most important sources of dietary carbohydrates
- potatoes, rice, wheat
Made up of 30% amylose and 70% Amylopectin
Glycogen is used for
Where is it stored in animals?
In cytoplasm, glycogen chains are attached to ____
Storage of flucose in animals, fungi, and bacteria
Stored in the liver and skeletal muscle
- Liver synthesizes glycogen from glucose when energy is abundant, breaks in down if not
- Skeletal muscle tends to store it uses it to power muscles during exercise
In cytoplasm, glycogen chains are attached to core protein glycogenin
Cellulose (polysaccharide)
Why can’t humans break it down?
Dietary fibers
Polysaccharide of glucose monomers responsible for rigidity of cell walls
- linked together via b-1,4 glycosidic bonds rather than alpha anomer in starch and glycogen
- Humans lack enzyme that can break this bond
However, important component of dietary fiber which play role in nutrient absorption and gastric motility, elminated as waste
Chitin (polysaccharide)
**Peptidoglycan (polysaccharide)
Structural support for shells or exoskeletons of insects, crustaceans, and mollusks as well as fungi cell walls
Makes up bacterial cell wall
Cyclization of linear monosaccharides forms
What happens to anomeric carbon when linear monosaccharide cyclizes
Either furanose: 5 carbon rings or pyranose: 6 carbon rings
Anomeric carbon functional group changes from aldehyde or ketone to hemiacetal or hemiketal
- alcohol attacks carbonyl carbon
Depending on which side the OH group attacks the anomeric carbon, either form alpha anomer or beta anomer
alpha anomer vs. beta anomer (monosaccharides)
Why does it matter?
Mutarotation: Alpha and beta anomers can rapidly interconvert
Alpha anomer: hydroxyl group points down
Beta anomer: hydroxyl group points up
Type of anomer formed affects the type of glycosidic bond that forms between sugars
Glycosidic Bond Hydrolysis Mechanism
Reverse of dehydration reaction in bond formation
- OR group attached to both sugars is protonated by an acid, forming leaving group
- Molecule of water attacks anomeric carbon in glycosidic bond kicking off protonated OR group
- Newly added water molecule deprotonated to form OH group
Maillard Reaction (redox with carbs)
**Reducing sugars
Gives food its distinctive brown color when burned; occurs between 140 and 160 deg C
- Amino acids in foods react with certain carbohydrates
- happens faster under basic conditions, amino groups deprotonated
- At very high temps, carcinogen acrylamide can form if the food is charged
Reducing sugars act as reducing agents with amino acids
- All monosaccharides
- any sugar with free aldehyde and non-aldose sugars that can be converted to an aldose (fructose)
- due to keto-enol tautamerism
- disaccharides and polysaccharides with free anomeric carbons
Cu2+, Ag+, Fe3+ detect reducing sugar presence in reactions
Testing for reducing sugars is critical for:
Tollen’s test
Benedicts test
Diagnosis of diabetes; diabetics have abnormally high blood glucose from not producing enough insulin or cells not responding to it
- excess glucose ends up in urine
Fehlings test was also used for detection
Silver ions used to oxidize an aldose (reducing sugar) which produces solid silver
Similar reaction with Cu2+ instead; begins with bright blue color and turns into red
Stereoisomers
Chiral center
Enantiomer definiton
Isomers that differ in the spatial arrangment of their atoms around a stereocenter
Chiral center is a stereocenter bound to 4 different substituents
- enantiomers: a molecule with a single chiral center is asymmetrical, non-suuperimposable on its mirror image
** Number of possible stereoisomers doubles with each stereocenter
Superimposable definiton
Ability of an object to be placed over another object
Achiral molecules or meso compounds (multiple chiral centers that form a plane of symmetry
Carbohydrates tend to have ____ chiral carbons
Chirality of each carbon is important because
1 to 5
Chirality of each carbon is important because it changes biological function and glycosidic bonds capable of forming
Diasteroemers
Differ at one or more stereocenter/chiral center, but not all of them (then they’d be enantiomers)
d/l (+/-) system for carbohydrate stereochemistry
(rotation of plane-polarized light)
Classifies compounds based on how they rotate plane-polarized light in a device called polarimeter (has to be determined experimentally)
- Chiral molecule either rotates light CW or CCL
- different from uppercase D/L
d-compound(+) rotates light clockwise
l-compound(-) rotates light CCW
R/S system
Go-to system for describing compounds with 1 or two stereocenters
R = clockwise
S = CCW
Priority Rules:
- Identify stereocenters
- Assign priority of groups by higher atomic number, then mass, then # of bonds
- Lowest priority group points away (dashed line)
- Assign R/S designation
One non-superimposable mirror image will be R and the other will be S
D/L system
Based on the fischer projection of glyceraldehyde (3-carbon aldose) which has one stereocenter
- enantiomers have one with hydroxyl group pointing right, one with hydroxyl group pointing left
- Hydroxyl group pointing right is D-isomer
** For compounds with more than one stereocenter, look at OH group on the highest numbered Carbon
- If pointing to the right, D
- if left, L
**Only D-isomers in biological processes
Do enantiomers of carbohydrates (and any molecule) interconvert at equilibrium?
No, only D sugars are used in biological process
Enantiomers
Stereoisomers that are non-superimposable mirror images
- configuration is opposite at each stereocenter
Epimers
Type of diastereomer that differ at ONLY one stereocenter
1 epimer for every chiral center
D-Glucose different stereoisomers
16 stereoisomers
- 2 enantiomers
- 14 diastereomers
- 4 epimers
Cyclic Carbohydrate conformations
Which are most stable for 6 carbon rings (pyranoses)?
For furanoses (5 member rings)
3D structures that can be rearranged without breaking bonds
Pyranoses: Most stable are chair and boat, whichever form is less directly hindered predominates
Furanoses: Most stable are envelope
Immune System 2 primary functions
- Prevent foreign pathogens from entering the body
* through physical barriers (skin), antimicrobial enzymes, and immune cells - Destroy any pathogen that manages to slip through
- as well as damaged or infected host cells
- because of its ability to attack host cells, one of the most powerful organ systems; dysfunction can damage/destroy healthy tissue
How does immune system distinguish pathogens from host cells?
Antibodies: Y shaped protein structures produced by B cells of the immune system
- track down and bind to pathogens
Antibodies structure (3 regions)
3 regions:
1. Constant- same across all antibodies
2. Variable- differs in order to detect different types of antigens (foreign molecules)
3. Hypervariable- also differs; contains antigen binding site that recognizes and binds a singular antigen
- one to one specificity of antibody to antigen
Antibody-antigen binding
Antigen binding site: undergoes extensive genetic recombination in B cells to create diversity to detect infinite range of antigens
- located in antibody hypervariable zone
Antigen-antibody binding marks the pathogen, makes it harder to infect host cells, makes pathogen easier to find and destroy
Antibodies distinguish “self” proteins from “non-self” proteins
Antigen
Epitope
Any recognizable component of a pathogen
Epitope: site where an antigen is recognized by an antibody
- specificity helps prevent immune system from targeting healthy tissues
Immune Cell Types
5 types
Abundance and function
Referred to as white blood cells or leukocytes
- Produced in bone marrow and nucleated (UNLIKE more abundant red blood cells)
Neutrophils: most abundant leukocyte (60%); track down pathogens like bacteria and destroy by phagoctyosis (classified as phagocytes)
Lymphocytes: 30% of white blood cells; T cells and B cells (B cells produce antibodies), as well as natural killer cells which target and destroy infected host cells
Monocytes: 5% of leukocytes; largest by size, **differentiate into macrophages and dendritic cells
-
macrophages: phagocyte; dispose of cellular debris and non-cellular foreign material
- non-specific phagocytes that engulf and digest almost anything, including cellular debris, tumor cells, foreign substances, and microbes.
- dendritic cells:
Eosiniphils: target parasistic infections
Basophils and mast cells: inflammatory cells, release histamine as part of allergic response
Neutrophils
Lymphoctyes
Lymphocyte maturation
30% of white blood cells; T cells and B cells (B cells produce antibodies), as well as natural killer cells which target and destroy infected host cells
-
ADAPTIVE immune cells
- antigen specific- each T or B cell will only target a specific group of structurally similar antigens
During maturation, undergo genetic recombination creating diverse set of cells
Monocytes
Eosinophils
Eosinophils are a type of disease-fighting white blood cell. This condition most often indicates a parasitic infection, an allergic reaction or cancer
Basophils and mast cells
Inflammatory cells, release histamine as part of allergic response
Granulocytes
Immune cells that contain cytoplasmic granules(small particles, usually for storage) rich in proteolytic enzymes
- Neutrophils- neutral color
- Eosinophils- acid-loving granules, stain red with acidic dyes
- Basophils and mast cells- base loving dyes, stain blue with base loving dyes
Bone Marrow
Hematopoiesis
Viscous tissue present in the interior of most of the larger bones in the body
Hematopoiesis: production of red and white blood cells in bone marrow
- hematopoietic stem cells can differentiate into T cells, B cells, neutrophils or other white blood cells
- also produces red blood cells and megakaryocytes (precursor to platelets)
Diseases that attack bone marrow
Treatment involves
Leukemia and other cancers of the blood, comprimises the immune system because of bone marrows function
Treatment involves radiation followed by infusion of new hematopoietic stem cells (bone marrow transplant)
- shows promise in treatment of HIV and others as well
- both known cases of curing HIV were transplans of bone marrow from healthy donor who had HIV immunity
Spleen immune system function
Parts of spleen known as white pulp are rich in lymphocytes and important for B cell activation
Thymus
Small organ in the chest where T cells mature (education)
Lymphatic system anatomy
What is lymph
Lymph nodes
System of vessels that helps transport fluid and immune cells throughout the body
- As blood flows through capillary vessels, some of this fluid leads into the tissues and collects in interstitial space
Interstitial fluid drains into lymphatic vessels in the form of lymph:
-
lymph: colorless, lipid-rich fluid that flows through lymphatic system
- eventually is returned to venous circulation
lymph nodes: pockets of lymphatic tissue that house high concentrations of T and B cells; swell during periods of infection, hundreds located throughout body
Lymphatic system also connects thymus and spleen
Lymphatic system four main functions:
What type of biomolecule is transported?
- Maintaining fluid balance
- Collecting and returning interstitial fluid to circulation
- Transporting cells and biomolecules within lymph (LIPIDS)
- Producing lymphocytes
Autoimmunity
Occurs when…
examples of autoimmune disorders
Any action of the immune system directed toward healthy host tissues
- Antigen-antibody system to prevent wrongful attack
Occurs when immune response is too strong
ex. Rheumatoid arthritis- autoimmune disorder where immune system attacks joints causing systemic joint pain
ex. Allergic response- immune system attacks harmless foreign body; can induce anaphylactic shock
* might be caused by lack of exposure to antigens
Histamine
chemicals your immune system makes. Histamines act like bouncers at a club. They help your body get rid of something that’s bothering you – in this case, an allergy trigger, or “allergen.” Histamines start the process that hustles those allergens out of your body or off your skin.
- Once released from its granules, histamine produces many varied effects within the body, including the contraction of smooth muscle tissues of the lungs, uterus, and stomach; the dilation of blood vessels, which increases permeability and lowers blood pressure; the stimulation of gastric acid secretion in the stomach; and the acceleration of heart rate. Histamine also serves as a neurotransmitter, carrying chemical messages between nerve cells.
Also in many stinging animals venom
Two divisions of the immune system
Innate immune system (army) and adaptive immune system (spy)
- work separately and in tandem, like when helper CD4 T cells recruit neutrophils, macrophages and other innate immune cells
Innate immune system (army)
What is used for protection against pathogens entering the body?
Broad, non-specific protection against microbes to prevent infections; acts very quickly!
- Prevent pathogens from entering body and bloodstream
- Skin (epidermis)
- Mouth
- Other major orifices: nasal and ear, rectum, urethra rectum vagina
-
Cellular response
- inflammation
Adaptive immune system (spy)
Specific targets its weaponized against; LYMPHOCYTES (T and B cells)
- antibodies
Remembers pathogens!
Epidermis immune functions
skin (epidermis)- cells are packed very tightly, making it difficult for foreign bodies to slip through
Sweat and shedding of skin naturally clears potential infectious pathogens
Mouth
Pathogens that survive oral cavity?
Saliva contains antimicrobial lysosyme which breaks down bacterial cell walls
- pathogens that survive oral cavity are likely to be damaged/destroyed by acidic environment of stomach
If bacteria makes it past the stomach
It has a chance of being abosrbed in intestinal lining or will pass through and be excreted
- even if bacteria attempt to colonize the intestines, growth is limited my healthy gut flora already present
What blocks entry of pathogens into ear
Tympanic membrane
How does nose, rectum, urethra and vagina block entry of pathogens?
Mucous lined membranes
Cellular response to an immune infection
- Most abundant leukocyte, Neutrophil is first on the scene of an infection
- follows a chemical trail of chemotaxic signals where it begins phagocytizing invasive bacteria
- Macrophages also phagocytize cellular debris
Inflammation
4 signs of inflammation
Necessary part of protecting and healing responses to injury and infection
- immune response to presence of foreign pathogens
1. Calor- heat
2. Dolor- pain
3. Rubor- redness
4. Tumor- swelling
Basic method of inflammation
Vasodilation of blood vessels at sight of injury or infection –> increased blood flow
- allows immune cells to travel quickly
Pathways that upregulate or downregulate inflammatory response are partially regulated by
Cytokines
Interferons
Immune response for viruses
T Cells
Two subclasses
Lymphocyte (adaptive immune system) that is matured in the Thymus (“T” cell)
- produced during hematopoiesis in bone marrow
- ANTIGEN PRESENTING CELLS:
Divided into two classes depending on response to Major Histocompatibility Complex (MHC) on the surface of other cells
- Most cells in body express MHC-1 receptors
- when cell is damaged, displays antigen on MH1 receptor which is recognized by CD8 T cells who lyses it
-
MHC-2 receptors are only found on immune cells like macrophages and dendritic cells who phagocytize antigens and present antigens to T cells
- antigen at MHC2 receptor interacts with helper CD4 T cells, which secretes cytokines that activate/recruit other innate immune cells
T-cell maturation
Faulty maturation can lead to
T-Cells must survive two phases which elimnate under or overreactive ones = Positive Negative Selection
- T-cells that fail to respond to general antigens are eliminated by positive selection
- T-cells that attack self proteins and are too reactive are elminated by negative selection
Rheumatoid arthritis
Crohns Disease
Lupus
Multiple sclerosis
When a normal cell is infected with a virus…
When antigen presenting cell engulfs a microbe and presents its antigen on MHC 2 receptors…
After serving their duty as effector T cells, both CD4 and CD8 T cells can differentiate into…
It expresses viral antigens on MH1 receptors so that CD8 killer T cells can destroy them and curtail infection
Activate helper CD4 cells to mount appropriate response
Memory T cells that remember antigen they were exposed to and mount a faster response next time
Memory T cells
How we develop immunity. Come from used T cells that differentiate after doing their job
Used to create vaccines
B Cells - adaptive immune system humoral response
B cells are produced in the bone marrow and their primary function is to secrete antibodies, which bind to antigens and mark them for destruction
- after production in bone marrow, migrate to secondary lymphatic organs like lymph nodes and the spleen, where they can interact directly with antigen presenting cells
If B Cell encounters antigen it has a receptor for, it either matures into a plasma B cell which produces antibodies or a memory B cell
Cell mediated response
Humoral response
T cells
B cells, antibodies
Cytoskeleton function
- Shape and structure
- Motion
- Cell division
- Organelle and biomolecule transport
Cytoskeleton structures (3 protein polymers)
1. Microfilaments
2. Intermediate filaments
3. Microtubules
Cell can add or remove protein subunits for each type of polymer to control filaments length or thickness
Microfilaments are composed of ____ proteins
Microfilament function
Actin
- Essential to cellular motility and maintaining cells structure (more rigid)
Also contribute to cytokinesis in cell division
And interact with myosin for muscle contraction
individual Actin monomers are called
Monomers are strung together to form
G-actin because of their globular shape
F-actin polymer (filamentous actin)
- Typically, two strands of F-actin stuck together to form microfilament
Treadmilling (cytoskeleton)
Microfilaments are directional;
- ATP bound actin monomer latches on to + end of elongating filament, which is hydrolyzed into ADP
- Therefore + end is ATP heavy and - end is ADP heavy and shrinks
- Caps can be placed at either end to stop this
When both happen at the same time, it is treadmilling and is reason that cytoskeleton has dynamic rapid growth and disassembly
_**_This also occurs for microtubules
Intermediate filaments are
Where are they found and what do they do?
Made up of different protein monomers; more stable and don’t bind nucleotides like other two cytoskeleton fibers
- alpha helical structure makes them more flexible
Typically found in cytoplasm providing structural support
- also adhere to other cells and position organelles
ex. Keratin (hair and nails)
Microtubules function
Where do they function
Structural support for cilia and eukaryotic flagella
Chromosome separation during mitosis/meiosis
Intracellular transport
Function at Microtubule Organizing Centers (MTOCs): basal bodies in cilia and flagella and centrosomes
Basic structure of microtubule
How does polymerization occur?
Monomer unit is actually a Tubulin dimer, composed of alpha tubulin and beta tubulin
Like microfilaments, have nucelotide binding sites, but instead are for GTP and GDP
- Polymerization occurs when theres a high enough concentration of dimers to exceed threshold
- depolymerization below this threshold
3 types of motor proteins
**Attach to cytoskeletal filaments
- Kinesins
- Dyneins
3. Myosins
Motor protein functions
Transport, motility, muscle contraction
Kinesins
anterograde transport
Made up of 4 subunits
ATP-ases: consumes energy from ATP hydrolysis to power movement
- Travel along microtubules to transport cellular cargo
- Anterograde transport: Move towards positive end of microtubule (towards periphery of the cell, away from center of cell)
4 subunits:
- 2 are heavy chains, function like legs
- Head groups = feet
- Stalks between head groups and heavy chains
- 2 heavy chains bind to two light chains which attach to cargo
How do kinesins move
ATP binds to a head group which locks it to microtubule and triggers conformational change, swinging second head group forward (toward positive + end)
- Then ATP is hydrolyzed to ADP causing it to detach
Dyneins
Their transport is called
Two types of Dyneins
Like Kinesins but move to (-) negative end of microtubules, towards cell center, also an ATP-ase
- Retrograde transport
1. Axonemal- only in cells with cilia or flagella, generate motion for these structures to move
2. Cytoplasmic- transport cargo, organelle and vesicle components
Myosins
3 domains
Also an ATP-ase
- used for muscle contraction
Composed of head, neck, and tail domains
- Head domain binds actin and hydrolyzes ATP to power myosins movement
- Tail binds to cargo and other myosin
Cell Adhesion Molecules (CAM) proteins
3 types of CAMS
Proteins on cell surface that glue cells together
- Associate with cytoskeletal elements or
- Anchor to eachother and extracellular matrix (network of proteins, sugars, other biomolecules
Cadherins, selectins, and integrins
Selectins (CAM protein) function
Found on…
Function: mediate inflammatory response
Found on immune cells, platelets, and endothelial cells lining blood vessels
- They bind to leukocytes moving through bloodstream, slowing them down to allow them to work at infected area
heterophilic- two pieces binding are different
Cadherins
Transmembrane proteins that bind to other cadherins for cell growth and development, cell adhesion
- contain calcium ions, dependent on them for adhesion
Homophilic
Integrins
Adheres to extracellular matrix and is used for cell signaling, binding ligands and cations (receptors of other cells)
- located on cell membrane
INTEGRATES cell adhesion with cell signaling
Cell junction types
Anchoring junctions
Gap junctions
Tight junctions
Anchoring junctions
Connect cytoskeletons to each other or to extracellular matrix
- help stabilize cells and tissues
Adherins junctions- cadherin proteins interact with actin filaments
Desmosomes- cadherin to intermediate filaments; located where withstanding force is necessary- heart, bladder, epithelial
Gap junctions
Created by connexin proteins, link cytosol of neighboring cells
- facilitates cell to cell communication
Allows passage of amino acids, Ca, cAMP
Found in most tissues but most relevant in tissues that require electric/chemical signaling
- ex. cardiac muscles (cells can contract at same time)
Tight junctions
Found in epithelial cells, link cells very closely and doesn’t allow passage of macromolecules, only water and some ions
- occludin and claudin proteins
ex. Blood brain barrier
Antibodies are
Chain components
Y shaped immunoglobulins
- glycoproteins made by B cells
- Antibodies help neutralize foreign invaders like viruses and bacteria as well as threatening cells in the body
Two heavy chains(longer), two light chains connected by disulfide bonds
- constant, variable, hypervariable
Can be secreted as dimers, tetramers, etc linked ny the STEM of their Y shape
Antibody classes are known as
5 classes
Isotypes- different functions in immune response
- IgA- blocks pathogen attachment in intestine, respiratory tract, saliva, genital tract
- IgD- antigen receptors on surface of naive B cells
- IgE- allergic and antiparasitic immunity (stimulates histamine)
- IgM- early response
-
IgG- most common, in blood and extracellular fluid
- eliminates bacteria and viruses
Class Switching
B cells can change production of one isotype to another, repurposing their antibodies
- constant region changes but hypervariable (antigen binding site) stays the same
ELISA
Utilizes carefully picked antibodies to detect a substance of interest
Excretory system key structures
Kidneys, Ureters, Urethra, urinary bladder
Kidney and key components
Functional unit of the kidney
Bean shaped organs near back of abdominal cavity
- Renal arteries supply each kidney with blood which drains by renal veins
Each kidney is protected by tough fibrous layer called renal capsule
- inside, kidney itself consists of:
- Renal cortex: outer region
- Renal medulla: inner region
The functional unit of the kidney is the nephron, which spans both regions
- nephron consists of renal copuscle and renal tubule
Nephron
Filtrate? Path of Urine through kidneys
- The functional unit of the kidney is the nephron, which spans both regions
-
nephron consists of:
- renal copuscle: flood is filtered into nephron, located in renal cortex (outer region of kidney)
- renal tubule: filtrate travels through renal tubule until reaching collecting duct, then drains as urine
-
nephron consists of:
Filtrate: water and solutes which eventually become urine
- Once urine drains from collecting duct, passes through medullary pyramids into minor calyces and then into major calyces
- urine then drains from renal pelvis which becomes the URETER
Each kidney contains about 1 million nephrons
Ureters, Urinary Bladder, Urethra
Two tubes, one from each kidney, which brings urine from kidneys to urinary bladder that sits on pelvic floor
- urinary bladder contracts to excrete urine through the urethra
Release of urine through the urethra is controlled by
Internal and external urethral sphinctor muscles
- internal urethral sphincter controlled by smooth muscle and the autonomic NS
External urethral sphincter is made up of skeletal muscle and is controlled consciously
Renal corpuscle consists of
Glomerularis, a tight bundle of capillaries
- blood enters them from afferent arterioles BUT also exits from an efferent arteriole instead of a vein
and Bowmans capsule which wraps around the glomerularis
Filtration in the nephron
(in corpuscle) Blood traveling through glomerularis is subject to hydrostatic pressure which causes some water and small particles to filter into Bowmans capsule = filtrate
- filtrate consists of water, salts, vitamins, glucose and amino acids
Renal tubule (in the renal medulla) consists of
Functions (3)
Renal tubule has to adjust volume of filtrate, reabsorb valuable nutrients, expels waste
Proximal convoluted tubule- reabsorbs valuable nutrients (glucose, free aminos, water soluble vitamins, sodium)
- picked up by blood capillaries
Loop of Henle- has a descending and ascending limb; allows for retention of large amounts of water and solutes
- reduces volume of urine without reducing concentration
Distal convulated tubule
Most important function of nephron
Reabsorption of all glucose
- glucose concentration in blood is a sign of disease like diabetes; too much blood sugar to be reabsorbed
Countercurrent Multiplier System
Loop of Henle. descending and ascending limb functions
Concentration of sodium increases as you go deeper into renal medulla
Loop of Henle- has a descending and ascending limb; allows for retention of large amounts of water and solutes
- reduces volume of urine without reducing concentration
Descending limb: permeable to only water and not ions; as it goes into higher sodium concentration, water drains out of the loop of henle reducing its volume
- water is picked up by vasa recta blood vessels and returned to circulation
Ascending limb: permeable to ions but not water; Na and K ions flow out and are picked up by vasa recta
- at bottom of ascending limb its thin and allows for passive transport
- at the top, its thicker and needs active transport
Blood in vasa recta runs opposite direction as loop of henle
Excretory system regulates what 4 components of homeostasis
- Blood pressure
- Osmoregulation
- Acid base balance
- Nitrogenous waste
Excretory system regulation of blood pressure
Blood volume, pressure and osmolarity are regulated by:
Blood pressure regulated by cross sectional area of vessels, vasodilation, and also by fluid volume which can vary dramatically
- when someone is dehydrated, blood volume and pressure is low
Aldosterone: increases sodium reabsorption and therefore water reabsorption, increasing blood pressure
Angiotensin II: increases BP and stimulates aldosterone release
Antidiuretic Hormone: increases blood volume and pressure
**Atrial natriuretic peptide: decreases blood volume and pressure
Distal Convoluted Tubule and Collecting duct ( in Nephron) are acted upon by
DCT and collecting duct are acted upon by hormones:
- Aldosterone- stimulate sodium reabsorption
- Antidiuretic hormone (Vasopressin)- promotes water reabsorption
DCT: sodium, Ca, Cl, H ions reabsorbed and K, H can be secreted
- aldosterone promotes sodium and therefore water reabsorption here
- can also be acted on parathyroid hormone, which stimulates calcium reabsorption
Collecting duct: ADH acts to promote water reabsorption
Aldosterone
Regulated by? Mechanism?
Increases sodium reabsorption, promoting water reabsorption, increases plasma volume and pressure
Regulated by reinin-angiotensin-aldosterone axis
- juxtaglomerular cells stimulated by low blood pressure, low sodium, or sympathetic NS input to release enzyme called renin in kidneys
- Renin acts on angiotensinogen to make angiotensin I
-
ACE enzyme converts angiotensin I to angiotensin II, which triggers release of aldosterone from adrenal cortex
- also stimulates vasoconstriction
Antidiuretic Hormone (ADH) (Vasopressin)
Promotes water retention by increasing water reabsorption in collecting duct of kidneys
- promotion of aquaporins in collecting duct cells
Vasoconstriction, increases blood pressure and volume
HOWEVER, reduces osmolarity of blood (no effect on solute)
Atrial Natriuretic Peptide (ANP)
Hormone secreted by the heart to decrease blood pressure
- sodium retention in the nephron
Excretory system regulates blood pH
pH must be kept between 7.35 and 7.45
Blood pH is usually decreased by lactic acid and CO2 levels (bicarbonate buffer)
** excreting more protons in urine can also decrease aciditiy, inhibiting this can do the opposite
- done by Sodium-Proton exchangers
Removal of soluble nitrogenous waste
Urea is removed via excretory system
- urea is carbonyl containing 2 amine groups
- ammonia is a biproduct
- in excessive levels, becomes toxic to the body
Liver converts ammonia to urea which is secreted through nephron for excretion
Boiling does not require that Pvap > Patm; it only requires that Pvap = Patm.
Why is ice less dense than water
For most substances, the liquid becomes more dense as the average kinetic energy (temperature) decreases, and the solid is more dense than the liquid due to close-packing solid-state structures, resulting in the formation of the solid at the bottom of the liquid. However, as stated in the question, solid water (ice) is significantly less dense than the liquid form at 0°C (the melting/freezing point). Remember, the water molecule is bent (shown below), with a bond angle of approximately 104.5°. This, combined with the degree of hydrogen bonding that can occur between water molecules, yields a solid crystalline structure with relatively large amounts of empty space. As a result, solid water is less dense than its liquid form.
The MCAT will expect you to be familiar with N2 as a very inert gas. It makes up approximately 80% of the air you breathe, yet has no significant chemical reactions with your lungs – or with anything other than nitrogen-fixing plants. This information implies that nitrogen is very inert (unreactive). As such, it would serve as a good artificial atmosphere when working with reagents that might react with oxygen or other gases.
Ka =
Keq
Amines are
Derivatives of ammonia (NH3)
- when uncharged has a lone pair of electrons
WEAK BASES
Naming amines
When highest priority functional group, name ends with amine
- when anoother higher priority functional group, denoted by -amino
Primary amines have one alkyl group, secondary have two, and tertiary have 3
Nitrogenous bases are (what functional group)
Cyclic amines, some with two rings
Primary or tertiary amines have a higher boiling point?
Primary because more hydrogen bonding
- however H-bonding in amines isn’t as strong as alcohols or carboxylic acids due to electronegativity
Alkyl vs. Aryl amines
Aryl amines have aromatic substituent
- less basic than alkyl amines due to lone pair resonance
Imines contain
Carbon nitrogen double bond
Enamines contain both
Hybrid of two functional groups: alkenes and amines
ENamine
Imines and enamines are
Tautomers, can easily interconvert under acidic or basic conditions
Amides
Carboxylic acid derivatives, Nitrogen bound to carbonyl group
Extremely weak bases due to carbonyl withdrawing; considered neutral (amino acids)
Garlic, skunk spray, and rotten eggs have what in common
Created by thiols
Thiols
Boiling points compared to alcohols? Acidity?
Compounds with S-H group
- polar but capable of only weak hydrogen bonding
- much lower BP than alcohol
However, more ACIDIC than alcohols (still weak acids)
Thioethers
Sulfur and two R groups; tend to act as bases
- methionine
- biotin
Thioesters
Biologically important thioesters
Carboxylic acid + thiol
- derivatives of Coenzyme A = acetyl CoA (key intermediate in aerobic respiration and fat metabolism)
Disulfides
Two bonded sulfur atoms which are also bonded to an alkyl group RSSR
- Important aspect of tertiary structure of proteins
Like peroxides, which have oxygen instead of sulfur (ROOR)
stabilize the tertiary and/or quaternary structures of proteins
Role of lipids
Types of lipids
Energy storage, structural support to cell membranes, chemical messengers
- Fatty acids and derivatives
- Cholesterol and derivatives
- Eicosanoids
- Terpenes and terpenoids
Fatty acid structure
Fatty acid derivatives
Fatty acids are commonly stored as
Lipid with acidic functional group (carboxylic acid attached to linear hydrocarbon chain)
- Fatty acid derivatives:
- triglycerides
- phospholipids
- sphingolipids
Fatty acids are commonly stored as TRIGLYCERIDES
Head of a fatty acid
Tail
Carboxylic acid
Hydrocarbon chain
Triglyceride structure (fatty acid derivative)
Triglycerides are stored in ____ for what use?
3 fatty acid chains, esters, glycerol
- typically what we consider fats in our food
Stored in adipocytes as energy reserves
Saponification
What about structure of soap makes it function?
Esters are carboxylic acid derivatives that can be split into components via nucleophilic reaction
- When this happens to triglycerides, its called saponification (soap making)
Done by mixing fat with a strong base, cleaves the triglycerides making glycerol and fatty acid salt
- Cation and carboxylate anion and fatty acid tail is excellent for solubilizing hydrophobic dirt/grime
Sphingolipids (fatty acid derivative)
Sphingomyelin
Fatty acid residue bonded to sphingosine amine group
Tendency to cluster in lipid rafts within plasma membrane; biosignaling
Waxes (fatty acid derivative)
Composed of a mixture of lipids
- produced by plants and animals
- solid but malleable at room temp
Cholesterol
What is cholesterol a precursor for?
Component of cell membranes (maintains fluidity), orchestrates secondary sex characteristics through steroid hormones, and regulating calcium metabolism
4 FUSED RINGS
- precursor for steroid hormones
- aldosterone
- estradiol
- vitamin D- regulating calcium metabolism
Eicosanoids (lipids)
2 subclasses:
Signaling lipids –> allergic response, pain perception, blood pressure regulation
-
Prostaglandins: synthesized from arachidonic acid
- mediate pain and inflammatory responses
- Thromboxanes: found in platelets, facilitate blood clotting
Terpenes and terpanoids
Terpenes = class of hydrocarbons made from isoprene (5 carbon unit w/ 2 double bonds)
- terpanoid: terpene with additional functional groups
Vitamin A (retinol) is a terpanoid
Lipid soluble vitamins
A, D, E, K
Vitamin A = terpanoid
Vitamin D = cholesterol derivative
Unsaturated vs. Saturated fats
Saturated fatty acids have no double bonds
- saturated with hydrogen bonds
Unsaturated have at least one double bond
Fatty acid naming
Numbering chain starts with carbonyl carbon, any double bonds are named by the lower number
- Z = cis
- E = trans
Lipid Numbering
Only gives total number of carbons and double bonds
ex. 16:1 Fatty Acid
Omega Fatty Acid Naming
Numbers carbon chain from hydrocarbon chain first
- opposite of IUPAC
Delta Fatty Acid Notation
Used to identify position of double bounds in fatty acid chain
- same as IUPAC; starts counting at carbonyl
Unsaturated Fatty Acids
Trans fatty acids
Usually have a cis bend that creates a kink in the hydrocarbon chain, causing loose packing
- LOW melting and boiling points
Sometimes liquid at room temp
Trans fatty acids: contain trans double bonds, more stackable than cis
- more likely to be solid at room temp
- Additive to food, greatly elevate risk of heart disease
- *increases LDL:HDL ratio
SATURATED fatty acids
Tight packing, high melting point, solid at room temp
How do lipids travel through bloodstream?
Lipoproteins: vehicles for lipid transport
- lipids absorbed by brush border in small intestine
- Packaged into chylomicrons- lipoproteins composed of triglycerides
* also contain apolipoproteins: amphipathic proteins that can bund lipids while interactring with polar solvents
After chylomicrons are formed with triglycerides
They are released into lacteals, small vessels that drain into lymphatic system
- from here, deliver fatty acids to adipose tissue, skeletal muscle, and cardiac muscle
After delivering lipid cargo, chylomicrons are repurposed in the liver
Liver produces important lipoproteins
Identified based on density (LEAST dense has HIGHEST ratio of lipid to protein):
VLDL (very low density lipoproteins): very rich in triglycerides, delivers them to body tissues
VLDL (very low density lipoproteins):
very rich in triglycerides, delivers them to body tissues
- triglycerides come from fatty acids synthesized in the liver and chylomicron leftovers
Circulates bloodstream releasing TGC’s, is converted to LDL
IDL (intermediate density lipoproteins)
VLDL is converted to IDL in the bloodstream after dropping off TGC’s
- some IDL particles return to liver, others become converted to LDL
LDL (low density lipoproteins) main function:
High LDL means
- converted from IDL after dropping off more TGC in bloodstream
Contains more cholesterol than triglycerides
- **main function is to deliver cholesterol
High LDL = increased cardiovascular risk, contributes to formation of atherosclerotic plaques
HDL (high density lipoprotein)
High HDL means
Picks up stray cholesterol and other lipids and brings them back to the liver
- Cholesterol transporter
High HDL = good cardiovascular health, decreased risk of atherosclerosis, unhealthy narrowing of blood vessels from plaque buildup
How are fats mobilized from adipocytes/adipose tissue to be used for energy metabolism?
Hormones epinephrine and glucagon tell adipocytes to release fatty acids
- active the enzyme hormone sensitive lypase, which hydrolyzes triglycerides
Free fatty acids released into bloodstream and are transported to target tissues by blood protein albumin
Breaking down fats for energy is two processes:
Lipolysis and beta-oxidation
Lipolysis
Fatty acid molecules are mobilized from storage and moved to bloodstream to be picked up by cells that need energy
- Triglycerides mobilized from adipose tissue made up of adipocytes
- hydrolyzed into glycerol and fatty acid chain components
Carried by albumin
Beta-oxidation overview function
Free fatty acids in mitochondria are broken down into
Fatty acids are oxidized to produce intermediate molecules which produce energy
- ** After lipolysis, free fatty acids enter cells from bloodstream and are shipped into mitochondria
Broken into Acetyl CoA’s (2 carbon molecule)(much more than made by pyruvate decarboxylation)
- can be fed into CAC to generate ATP via aerobic respiration
How do free fatty acids enter mitochondria membrane for beta-oxidation?
To enter matrix?
Moved from cytosol into mitochondrial matrix by adding a molecule of Coenzyme A, creating Acyl CoA
- fatty acid can’t enter mito without it
Short fatty acid chains can diffuse into matrix, longer chains have to use carnitine shuttle (reference picture)
- serves as a control point for regulating fat metabolism
- only active when cell needs fat for energy
Steps of Beta-oxidation of an even numbered saturated fatty acid
- Goal is to get 2-carbon acetyl CoA; each round liberates 2 carbons from polar head of fatty acid
- Each round takes place in 4 steps:
- Oxidation
- Hydration
- Oxidation
- Thiolysis (cleavage)
Step 1: Beta Oxidation: Oxidation
Acyl CoA Dehydrogenase creates double bond between beta and alpha carbons adjacent the carbonyl
Produces 1 FADH2 and trans-∆2-enoyl-CoA
Step 2 Beta Oxidation: Hydration
Product of 1st oxidation has addition of hydroxyl group to beta carbon which used to be part of double bond created in first step
- double carbon bond is used to add oxygen
Step 3 beta oxidation: Oxidation
The hydoxyl added in step 2 is oxidized further into a carbonyl group
- creates one NADH from NAD+
Creates Keto
Step 4 Beta oxidation: Thiolysis (cleavage)
FRESH molecule of COENZYME A cleaves the fatty acid into molecule of Acetyl CoA and new fatty acid that is two carbons shorter
Beta oxidation of an unsaturated fatty acid with an odd numbered double bond
Beta-oxidation proceeds normally until it meets double bond
-
Odd numbered double bonds dealt with by enzyme enoyl-CoA isomerase
- moves double bond to an even number
- fatty acid becomes another trans-∆2-enoyl-CoA and can proceed with second step of beta O (hydration)
Beta oxidation of fatty acid with ODD number of carbons on chain
Process halts with 5 carbons remaining: creates 1 acteyl CoA and 1 propionyl CoA
Propionyl CoA can be turned into Succinyl CoA and enter citric acid cycle
Each round of beta oxidation produces
How much ATP?
Each round produces 1 FADH2, 1 NADH, 1 acetyl CoA (final step produces 2 acetyl CoA or 1 and 1 propionyl CoA)
About 14 ATP per 1 round (multiple rounds for a fatty acid chains)
- 7n ATP per “n” carbon in chain
Ketogenesis
Liver can convert Acteyl CoA into
Ketone bodies, small 3 or 4 carbon molecules soluble in the bloodstream which can be sent to tissues during periods of fasting (glucose used up)
3 main ketone bodies:
- acetoacetate - one to know
- acetone
- D-B-hydroxybutyrate
Fatty Acid synthesis
1st step
Occurs in the cytosol
- Acetyl CoA is activated to malonyl CoA (addition of carboxyl group)
- An acetyl CoA group and malonyl CoA group are “loaded” onto ACP of fatty acid synthase
Cholesterol Synthesis 2nd step
3 molecules of ATP used to transform mevalonate into two activated isoprene molecules
- 6 isoprene molecules condense to form squalene which goes on to form cholesterol
Cholesterol from liver delivered via bloodstream to tissues within LDL lipoproteins
Stereotypes
Contentful- what we assume about people
- Cognitive- as opposed to prejudice which is emotion-based
a widely held but fixed and oversimplified image or idea of a particular type of person or thing.
Generations
Categorizing age by cohorts
Demographic Transition
Stage 1: death rate and birth rate are high; stable or slow increase
Stage 2: birth rate remains high, death rate falls rapidly
- very rapid increase in pop
Stage 3: death rate still decreasing, birth rate falling
- increases in pop slow down
Stage 4: both slow, growth is stable
Possible stage 5, decreasing population and increasing age
Population Pyramid
Dependency Ratio
Visualize balance of age and gender groups in society
Dependency ratio = [(# of ppl 0-14)+(# of ppl 65+)] / (# of ppl 15-64)
- Rough estimate of number of people workforce must support
Great Depression
1929-1939; serious deprivation and poverty, lasting impact on generational cohorts
Migration in the US
Push factors
Pull factors
Periods of heavy and light migration in the US
- very common in late 1800s early 1900s
- 1920s had laws put in places, reformed in 1960s which led to more immigration again
Push Factors: poverty, war, violence
Pull Factors: economic prosperity, social stability
Factors for hemoglobin saturation:
- Oxygen in the environment
- Ease of contact with O2 and hemoglobin binding sites
Michaelis Menten Model (Vmax and Km definitions)
100 molcules of enzyme X in a test tubel enzyme X catalyzes conversion of S –> P
- Vmax: MAX RATE, saturated, all molcules of X occupied
-
Km: conc of substrate (S) at HALF of Vmax
- how readily enzyme reacts w/ substrate
-
Km: conc of substrate (S) at HALF of Vmax
V = Vmax [S] / Km + [S]
Lineweaver-Burk Plots
Double reciprocal transformation of Michaelis Menten plots to make estimating Vmax and Km more precise
cAMP
Cyclic adenosine monophosphate - chemical signalling molecule
Speed of sound is affected by
Speed of sound equation
affected by medium through which it travels, fastest through incompressible material
- fastest through solids, slowest through gases
Also affected by density of medium: more dense = slower
bulk modulus (B): a material’s resistance to compression
V = √(B/P)
speed of sound = sq rt of bulk modulus / density
Light as a wave is termed an
Electrical and magnetic components relative to velocity (directional) component
Electromagnetic wave (transverse waves)
- can propagate through air/water but also a vacuum
Electrical and magnetic components, each perpendicular to each other and both perpendicular to the velocity component
Polarizing filter - circular polarization
Polarization where direction of electric and magnetic fields rotate steadily over time
- Right-handed or Left-handed
Used in optical dichroism to determine chirality
Electromagnetic Spectrum
Places each form of EM radiation on a scale according to frequency and wavelength
- gamma rays (low freq), X rays, UV rays, visible light, infrared, microwave, radio waves
Reflection
Bounces of surface of mirror at an angle symmetrical to angle of incidence
- relative to line perpendicular to the surface = normal line
Refraction
Refractive Index (n)
If wave travels from one medium into another
- changes speed of waves and bends the light
Light only refracts when it hits medium at an angle
n = c / v
- c = speed of light in a vacuum
- v = light speed in medium
n is always greater than 1; nair is pretty much 1
Total internal reflection
If angle of incidence is large enough when passing from one medium to another it can reach critical angle, where it reflects
- Light has to be moving from high n to low n
- Angle of incidence is large
Diffraction
Waves encounter a barrier with a small opening
- waves that hit the barrier are reflected back while waves that hit opening expand outward
Constructive/destructive interference leads to areas of intensity (maxima) and dark regions known as minima
Single slit diffraction
One aperture (hole)
AsinΘ = mλ
A = size of aperture
Θ= angle relative to original light beam
m = nth minimum
Thin Film Interference
Light waves reflect off top and bottom boundaries of a substance that forms a thin film
Parkinson’s disease biological basis
Symptoms: tremors, slow movements, loss of facial expressions, bent posture
Caused by cell death in substantia negra
- leads to reduced dopamine expression
Connective tissue - cartilage
Composed of what cells?
Flexible, rubber-like tissue
- no nerves or blood vessels
Composed of chondrocytes, cells that make the protein collagen (structural protein that strengthens and connects tissues)
Skeletal Categories
-
Axial
* vertical axis - skull and vertebral column, rib cage
2. Appendicular
- extremeties - pectoral girdle, pelvic girdle, upper extremity (arms), lower extremity (legs)
Compact bone
fundamental unit?
Hard and dense; structural support and movements
- fundamental unit is the osteon: cylindrical structures composed of concentric rings of bone matrix
- in the center of the osteon is the Haversion canal through which bones blood and nerve supply pass
Spongey bone
“Trabecular or Cancellous”
- spongy interior and porous
- less dense and stiff
Holes in it for blood vessels and bone marrow
Fasicle
Bundle of muscle cells encased in connective tissues
Muscle cells are also called
Myocytes or muscle fibers
Myocytes contain ___ which themselves contain
rod-like myofibrils which contain microfilaments of myosin and actin
- organized into repeating units called sarcomeres
Cytoplasm of muscle fibers
Contains?
sarcoplasm
- contains stores of myoglobin and glycogen
Muscle contraction
Sliding Filament Theory
Sarcomere: repeating unit in striated muscle cells containing myosin and actin
- smooth muscle doesn’t contain sarcomeres but contains myosin and actin fibers which can contract
Sliding Filament Theory: Myosin and actin fibers bind and tug at each other to shorten length of sarcomere
To cause muscle contraction, actin slides over myosin thick filaments at the center of the sarcomere
- Actin encroaches on H zone (only myosin) and overlaps with it, H-zone effectively shrinks
Sacromeres anatomy and Sliding Filament Theory
Sliding Filament Theory: Myosin and actin fibers bind and tug at each other to shorten length of sarcomere
- Actin (thin) filaments are anchored to Z-lines: form boundaries of the sacromere
M-line: middle of the sacromere
H-zone: spans length of sacromere that only contains thick myosin filaments with no overlap from actin (in middle)
I-band: spans region contains only thin actin filaments (near Z line)
A-band: spans entire length of myosin filament
Regulation of muscle contraction
Calcium
Myosin binding site in actin are by default blocked by the protein tropomyosin
- Only when calcium is present in cell, it can bind the protein troponin which moves tropomysin out of actin’s way so it can interact with myosin
Once muscle cell sarcolemma experiences depolarization from acteylocholine..
Action potential travels down sarcolemma to transverse (T) tubules that penetrate into the cell to the sarcoplasmic reticulum (smooth ER in myocytes)
- triggers opening of calcium channels causing sarcoplasmic reticulum to release stores of calcium ions
- intracellular calcium conc is usually very low
Calcium causes tropomyocin to dissociate from myocin binding sites on actin, allowing them to interact
Dermis mechanoreceptors
Ruffini endings (sense stretching)
Pacinian corpuscles (vibration/pressure)
Meissner corpuscles (sensitive touch)
Mirror
Convex vs. Concave
Any substance from which light rays reflect, without significant absorption or refraction
Concave curves towards the observer, convex curves away from the observer
Plane mirrors don’t curve
Focal point
Where incident rays converge
f = r/2
- concave, meet on same side as object
- convex, meet on opposite side
plane mirrors
Thin lens equation
Focal point and radius can be thought of as infinite
- O = distance of object, I = distance of image
1/O + 1/i = 1/f
Lenses are different form mirrors in that…
Which lens cause light to converge, which to diverge?
Light passes through them almost completely, bending or refracting
- *** Opposite of mirrors: convex cause light to converge
- Concave cause light to diverge
positive image value for lenses
negative image value
Real image is opposite and inverted
Negative = virtual image on same side as object
Systems with multiple lenses
mtotal =
Image generated by one lens serves as the object as the next lens, which in turn generates a second image
mtotal = m1 x m2…
What is glycogen
Center of glycogen polymer contains…
Glucose molecules in each chain are linked by
Branched polymer of glucose, thousands of glucose molecules strung together
- Center contains protein called glycogenin: attachment point for many individual chains of glucose which are themselves branched
Glucose molecules are linked by alpha 1,4 bonds
Glycogenesis steps
- Begins with glucose 6-phosphate (G6P) converted to G1P using enzyme phosphoglucomutase
- G1P converted to UDP-glucose (type of nucleotide, like GTP and ATP) which is derived from UTP
-
Glycogen synthase breaks UDP off and creates alpha 1,4 bond between new glucose and existing chain
* **glycogen synthase CAN’T create new branches
Glycogenolysis steps
Breakdown of glycogen for energy
- Breakdown of glycogen into glucose 1-phosphate by glycogen phosphorylase
- phosphorylysis: ***adds PHOSPHATE GROUP to glucose at the end of chain replacing the alpha 1,4 bond
- NEEDS glycogen debranching enzyme to break alpha 1,6 bond at the end of chains
- G1P into G6P by phosphoglucomutase
G6P can then enter glycolysis or gluconeogenesis depending on bodily needs
How is glycogen phosphorylase allosterically inhibited in liver vs. muscle cells
In muscle cells, calcium ions upregulate glycogen phosphorylase
- if muscle cells actively contracting, need glucose
- AMP is a sign of low energy, also upregulated glycogenolysis
In liver cells, glucose allosterically inhibits glycogen phosphorylase
