Lect Exam 2 - Cells + Bones!

cell

structural and functional unit of human body

-we have different shapes and sizes of cell depending on the location and funcs of cells

• all activities in body carried out by cell - they continue to divide

99% of cells in human body have 3 important parts *** EXTRA CREDIT

• plasma / cell membrane / plasmalemma

• cytoplasm

• nucleus

plasma membrane

makes outer (flexible) boundary of the cell

• separates inner stuff from outer stuff

cytoplasm

• in between plasma memb and nucleus

• contains fluid + some organelles

nucleus

• central hub of the cell that contains DNA in the form of chromosomes

we have fluid..

inside the cell: water + electrolytes - ICF (intracellular fluid)

outside the cell: ECF (extracellular fluid)

MOST IMPORTANT FUNC OF PLASMA MEMB

separate ECF: (water + electrolytes) and ICF: (water + electrolytes)

plasmalemma/cell memb/plasma memb components *****EXAM

• phospholipid bilayer made of phospholipids

• cholesterol (steroid)

• glycolipids/glycoproteins: glucoses/sugars attached to lipids or proteins

3 funcs of plasma memb

• most important func: acts as a mechanical barrier that separates the inside of the cell (which has ICF) from the outside of the cell (which has ECF).

• to be selectively/semi permeable - because plasma memb is made of lipids (hydrophobic), it will only things that are lipid/fat soluble to cross the plasma memb - anything that is watery won’t be allowed to pass thru

• to maintain an electrochemical gradient: keep things that have different charges where they should belong - keeping anything with charge in and out

• —> ***inside of cell we have neg charge and potassium (K+)- (no Na+ inside),

• outside of cell we have pos charge + sodium (Na+)- (no K+ outside) - —→plasma memb keeps this charge/electrical difference - the electrochemical gradient

func of cholest/steroid embedded n plasma memb **IN EXAM

• provides stability (strengthens) to the plasma memb

phospholipid bilayer

most important component of plasma memb: phosholipid bilayer

phosphate heads hydrophilic - they facing outside the cell and they facing inside the cell cuz we have water inside and outside the cell so water is not directly facing the lipids, which don’t like water

—> we have phosphate balls on the outside and inside of plasma memb so water doesn’t seep inside the cell! - phosphate heads won’t allow water to enter in but they can face (tolerate) the water.

lipid tails hydrophobic - are inside plasma memb as tails cuz lipids cant face water.

—

func of sugars attaached to plasma memb (glycoprot/glycolipid )

• sugars act as sensors that tells the cell whenever a bad (cancer etc.) cell comes near it. - act as cell signals

memb proteins are…

inserted into the plasma memb but is not a part of plasma memb!

2 types of memb proteins + what is memb prots’ func

• integral prots

• peripheral prots

• funcs:

• act as enzymes

• anchoring prots - things get attached to them

• recognition prots - they recognize good and bad cells (detected by cells of immune sys)

• receptor prots - bind to specific extracellular molecules called ligands

• carrier prots - bind solutes and transport across plasma memb

• prot channels - the passageway for solutes to enter the plasma memb

• carrier prots + prot channels - faciliate movement of things into and out of the cell

integral prots

AKA transmembrane prots

memb prots that start from where the plasma memb starts and ends where the plasma memb ends - run the whole length of the plasma memb - all the way through

peripheral prots

-memb prots that are either attached to the outside (upper part) of the plasma memb or attached to the inside (jnner side) of the plasma memb.

glycocalyx

sugary coat on the outer surface of plasma memb

-func: help recognition between good and bad things.

phospholipid struct

phosphate head - hydrophilic - faces outwards

lipid tail - hydrophobic - faces inwards

CELL MEMB SEPARATES ___ AND KEEPS

ECF + ICF - BOTH OF THEM MADE OF WATER + ELECTROLYTES(SOLUTES)

keeps electrochemical gradient

cytoplasm

• part of cell between plasma memb and nucleus

• is watery part of the cell

• made up of 3 things:

• —cytosol - most important + abundant - is water + electrolytes

• —organelles - tiny little machines within the cytoplasm that work for the cell

• —(inclusions) - they pigments like haemoglobin

membranous organelles

• surrounded by membranes

• mitochondria

• Peroxisomes

• Lysosomes

• Endoplasmic reticulum

• Golgi apparatus

non membranous organelles

• not covered by membranes

• Cytoskeleton

• Centrioles

• Ribosomes

• Cilia

• Microvilli

cytoskeleton

• gives internal support, strength, flexibility to cell - cell’s skeelton

• made up of thread-like proteins/filaments

• components (name of skeletons in cell?):

• -1. microfilaments

• =2. Intermediate filaments

  -3. Microtubules

microfilaments

• made up of actin prots

• smallest supports in the cell

• present in peripheries of cell

• part of cytoskeleton

intermediate filaments

• mid size

• strongest + most durable cytoskeletal elem

• funcs:

• Strengthen the cell and maintain its

shape

• Stabilize position of organelles

• Stabilize cell position

• part of cytoskeleton (type of cell skeleton)

microtubules

• biggest skeleton of cell (largest components of cytoskeleton)

• part of cytoskeleton (type of cell skeleton)

microvilli

finger like projections / tiny folds of plasma memb to increase the surface area of absorption

cilia

• hair like growths on the upper end of the cell (on plasma memb)

• move and keep things away from cell e.g. fluids you dont need

• non membranous organelle

centrioles

-cylinder-like organelles

• non membranous

• always seen in pair in a cell

• important role in cell division

• EXAM Q**: cells that do not have centrioles in them will not divide and will die!

ribosomes

• **func: MAKE PROTS!! EXAM

• MADE UP OF PROTEIN AND RIBOSOMAL RNA (rRNA) - **EXAM

• 2 types: free ribosomes + membrane-bound ribosomes

• free ribosomes: ribosomes that freely circulate in a cell that make PROTEINS WHICH ARE USED IN THE CELL

• membrane bound ribosomes/ bound ribosomes/ attached ribosomes : attached to memb of ER - MAKE PROTS THAT WILL LEAVE THE CELL OR GET INSERTED INTO THE PLASMA MEMB AS MEMB PROTS!!

• non membranous organelles

endoplasmic reticulum (ER)

• in the form of flat stacked interconnected tubes

• -usually seen attached to the nucleus

• 2 types of ER:

• → rough ER - has ribosomes attached

• —> smooth ER - no ribosomes attached

rough ER func

• same func as memb bound ribosomes cuz has those attached to it!

• —> make proteins that will leave the cell or be inserted into the plasma memb as membrane prots

smooth ER func IN EXAM!

• MAKE LIPIDS (STEROID CHOLEST ETC.!)

• LIPID METABOLISM: ABSORPTION, SYNTHESIS, TRANSPORT OF LIPIDS - dealing with all kinds of lipids!

• STORES CALCIUM!

• NO RIBOSOMES ATTACHED - SO IS SMOOTH!

mitochondria

• inner memb is folded

• folds in inner memb called cristae

• func: MAKE ATP ENERGY BY BREAK GLUCOSE!

• powerhourse of cell cuz make energy in the form of ATP by use (break) gluc

golgi body / apparatus

• usually attach to rough ER

• flattened membranous organelle

• ** func: modify, concentrate, package prots and lipids coming from the ER b4 they going out of the cell!**

• has 2 entrances/doors:

• - 1 is entrance door - cis face/door -door through which proteins will enter so they can be packed, will go through the golgi and then go to

• 2 is exit door - trans face/door - the door through which proteins will leave the cell

what is a vesicle

packed protein or lipid which will go out of the cell

peroxisomes

• spherical organelles

• func: detoxify substances/any toxins - make things less harmful! (neutralise them)

• they detoxify things thru 2 chemicals that are in them: oxidase (use oxy to make things less harmful) and catalase

lysosomes

• spherical organelles - memb bound

• func: phagocytosis of bad cells e.g. bacteria, cancer. -

• —> they eat up any bad cell by the process of phagocytosis and have special digestive enzymes in them that allow them to digest the bad cells!

nucleus

• 3rd part of the cell

• present in the centre of cell - spherical

• nuclear pores: pores in nuclear membs through which things can enter or leave the nucleus

• center of nucleus has NUCLEOLUS that makes ribosomes - ribos come out in the cytoplasm thru nuclear pores!

• 2 membs/envelopes of nucleus

• surrounded by nuclear envelope

• func of nucleus: store DNA!!!

DNA present in 2 forms in nucleus EXAM

• chromatin - when the cell is not dividing, DNA is in the form of chromatin - loose threads! - cell is just growing in size when chromatin

• chromosomes - condensed form of DNA that shows us the cell is dividing!!!

• when DNA is loosely wrapped around histone prots - is chromatin - tells not divide, just growing!

• when DNA is tightly wrapped around histone prots - is chromosome

• cell is divide

some cells.. but most cells..

1. freely roam in body e.g. blood sperm

2. attached to each other, bound in communities

cell community

• when cells attached to one another; bound in communities

junction AKA communications

• when cells attached to one another in a community!

• most cells connected to one another via junctions

3 types of junctions! with cell

• Tight junctions

  • Desmosomes

  • Gap junctions

tight junction

• junction/communication in which cells are connected by special prots to each other so tightly so* * nothing can pass thru them!**

• in urinary bladder

• continuous seal preventing molecules/anything from passing between/across cells

desmosomes

• tooth like/ velcro like junc that holds cells to prevent wear and tear (interlock)

gap junctions

• (cells) have tiny gaps iin between them so things can pass from 1 cell to another cell.

you see gap junctions and desmosomes..

in cardiac cells - cells of heart

when things move in and out of the cel..

that is movements/transport

permeable

some plasma membs is freely permeable - will allow everything to enter and leave!

some plasma membs are impermeable - wont allow anything to enter or leave

our plasma membs are semi perm- will allow some things to enter and not allow smth to enter

our plasma memb allows things to enter/disallow based on..

• size

• molecular shape

Electrical charge

• Lipid solubility

-so is semi permeable

2 types of transports

• passive transport/movement

• active transport/movement

charge inside cell is

negative - potassium

electrolyte + outside cell

• sodium
  pos charge

resting condition /resting potential/ polarised state of cell/RESTING MEMB POTENTIAL + ACTION POTENTIAL!

• neg charge + potassium in cell

• pos charge + sodium outside of cell

—WE DONT WANT SODIUM TO ENTER INTO CELL CUZ ITS VERY EXCITABLE

• WHENEVER SEND A MESSAGE INSIDE THE CELL, SODIUM WILL ENTER IN CELL, THIS EXCITES THE CELL CUZ SODIUM IS EXCITABLE - IS ACTION POTENTIAL

• ACTION POTENTIAL: ENTRANCE OF SODIUM INSIDE THE CELL AND CELL IS NO LONGER RESTING, IT IS EXCITED - EXCITED STATE IS ACTION POTENTIAL!

passive transport

movement of things from higher area (concent) to lower area (concent) WITHOUT ENERGY USE! (ATP)

• move down concent grad

• things will cont to move from high to low till balance (equilibrium) reached

active transport

• movement of things from lower area (concent) to higher area (concent) WITH ENERGY USE (ATP)

• things move from lower to higher gradient

types of passive transport AKA diffusion

• simple diffusion

• facilitated diffusion / helped movement

simple diffusion

• movement of simple things (oxy. co2, h2o etc.) from higher to lower area down concent grad) without ATP use

• '“SIMPLE THINGS = THINGS THAT ARE FAT SOLUBLE + WATER!

• type of passive transp

facilitated diffusion

• movement of anything which is not lipid soluble / is too big to cross the plasma memb moving from higher to lower area without the use of energy

• things e.g. gluc, AA - can’t cross plasma memb so will be facilitated

• - type of passive transp

• INTEGRAL PROTS WILL CARRY THOSE THINGS ACROSS PLASMA MEMB WITHOUT ENERGY USE - WILL HELP THEM

OSMOSIS EXAM

• MOVEMENT OF WATER FROM HIGHER WATER CONCENT TO LOWER WATER CONCENTRATION

• in plasma memb. we have holes called aquaporins that allows water move through from a higher concent to a lower concent

• MOVEMENT OF WATER FROM WHERE SOLUTE ARE LESS TO WHERE SOLUTES ARE MORE

• WATER LOVES TO GO TO AREA WHR SOLUTES MORE

• -flip em!

electrolytes are//

solutes

(TONICITY)

SOLUTES CAN AFFECT THE SHAPE OF THE CELL CUZ SHAPE OF CELL IS CONTROLLED BY WATER + ELECTROLYTES

ISOTONIC SOLU

NO WATER MOVEMENT WHEN NUMBER OF WATER + SOLUTES SAME INSIDE AND OUTSIDE!]

OUR BODY CELLS ARE LIKE THIS

hypertonic solu

-a solution which has more solutes as compared to cell

-water will move out of the cell - cell shrinks + dies

hypotonic solu

• water moves into cell - cell swells and burst

• solution in which solution has less solutes as compared with inside the cell

active transport + types

• movement of things from lower concent (area) to higher concent (area) - need ATP!

• - may need cuz too big, not lipid solu, cant be moved across plasma memb!

• 2 types:

• simple/primary active transp

• vesicular transp

primary active/simple active transp

• movement of things from lower to higher concent w/use of ATP

• E.g. sodium-potassium pump

vesicular transport

-e.g. of active transp needs ATP

• movement of things that are too big to an area by using energy

• Transport of large particles, macromolecules, and fluids across membrane in membranous sacs called vesicles

• 2 types:

• exocytosis - movement of things out of the cell

• endocytosis - movement of things into the cell

• —> 3 types: phagocytosis, pinocytosis, receptor-mediated endocytosis

• —→ pinocytosis: cell drinking, fluids e.g. nutrients as liquid come into the cell

• —→ phagocytosis: plasma memb of cell creates false feet around whatever it wants to eat (e..g cancer cell) and brings it inside the cell! -: false feet = pseudopods

• receptor-mediated endocytosis: cells have specialized receptors to which a spec thing will get attached and be brought into the cell e.g. spec receptor for gluc - only gluc will get attached to receptor and taken into the cell!

vesicle

• anythihg we want to transport out of the cell will be in the form of little packages called vesicles

memb potential

• when you have negative charge + potassium inside cell + you have pos charge and sodium outside cell - cell is in resting condition/resting memb pot / polarised state - plasma memb keeps charge + electrical diff in + out of cell

• - voltage inside cell can be -90 to -110 mV when cell in resting pot

DNA

• nucleotide made of pentose sugar, phosphate, nitrigenous base: ATGC

• DNA is larger molecule in nucleis

• important cuz has codes for make prots

• spec part of DNA which has recipes for making protein is called GENE

• double strand

RNA

• single strand

• AUGC

• made in nucleus

• 3 types:

• mRNA (messenger) func:

• rRNA (ribosomal) func:

• tRNA (transfer) func:

these RNA can exit nucleus + go into cytoplasm

2 processes in which proteins forned

• transcription

• translation

transcription

• 1 strand of DNA goes away when want to make prot

• a single strand of DNA gets mRNA attached to it

• mRNA copies protein codes cuz DNA cant exit nucleus cuz its big

• then will exit nucleus and go into cytoplasm

translation

• all the messages /prot codes mRNA has is then translated/ transferred to another RNA called tRNA

• tRNA will tell those protein codes to ribosomes and rough ER

• - protein synth will then start

cell cycle

phases of cell life

2 stages of cell cycle

• interphase

• mitosis

interphase

• phase whr cell grows in size

mitosis

• phase in cell cycle in which the genetic material (DNA) + cytoplasm divide into 2 equal daughter cells

• cell division in which 1 mother cell divides into 2 daugher cells in which the genetic material (which is DNA) + cytoplasmic contents will be equally distrib to 2 daughter cells.

mitosis phases EXAM

prophase

metaphase

anaphase

telophase

prophase

• in cytoplasm, we have 2 centrioles in each cell normally

• centrioles will double - we have 4 now

• from centrioles - spindle-like fibers/extensions will come out - we call em mitotic spindles

• 2 centrioles will move towards each end of cell

• in nucleus, DNA conv to chromosomes (2 sister chromatids connevcted tgt - connected to each other by centrosomes - a prot)

• nuclear memb disappears + chromosomes become free in cytoplasm

• mitotic spindles hold chromosomes by centromeres

metaphase

mitotic spindles bring chromosomes to centre of cell

anaphase

mitotic spindles separate sis chromatids + bring sis chromatids to opp ends of cell

telophase

cell starts to get pinched in the centre - starts to divide

dent formed between 2 cells is cleavage furrow - eventually deepens to form 2 daughter cells

cytokinesis

• process in which cytoplasm of cell begins to divide into 2

• cell is fully dividied

• 23 chromosomes in each of the daughter cells

we need cell division for

produce cells

allow for growth + repair of tissues

perichondrium **

• connective tissue covering/memb surrounding all cartilage that supplies it with blood cuz all cartilage is avascular

all cartilage is

avascular

no body cells can survive without

blood coming to it

cartilage cells

chondrocytes

lacunae

• cavities/spaces in which chondrocytes (cartilage cells) sit

(how bones formed)

• before u born - in mum’s uterus - all support for body was cartilage, which was later replaced by bones

• support for body was cartilage cuz is flexible, moldable, light weight, more resilient, made of more watery content

• after birth. all cartilage replaced by bones, and bones make up the skeletion/support of body now

3 types of cartilage

• hyaline cartilage

• fibrocartilage

• elastic cartilage

hyaline cartilage **EXAM

• seen mostly around ends of bones that make joints

ELASTIC cartilage

• see in ear ; rare

fibrocartilage

• seen in intervertebral discs

bones are what type of tissue

CT

funcs of bones

.1. Support

• For body and soft organs

2. Protection

• Protect brain, (vertebraes that surround) spinal cord, and vital organs (rib cage surrounds heart + lungs)

3. Movement - most muscles attached to bones and are resp for movement

4. Mineral and growth factor storage

• Minerals Calcium and phosphorus stored in bones, + growth factors stored in bone

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5. Blood cell formation

-rbc, wbc, platelets made in bones

• Hematopoiesis - process of blood cell formation by the bones

-6. (fat) storage

• Fat is stored in bone cavities

• VIT D PRODUCTION