Cells PPTX 3

Deductive reasoning

1. general theory

2. testing on specific case

3. making a garunteed conclusion

eg: all humans are mortal. caitlynn is mortal. therefore, she is human

Inductive reasoning

The opposite

1. starting with specific observations

2. making a probable conclusion

eg: notice all swans are black. thus, all swans are black

Units in biology

nanometer: smallest

micrometer: nano x 1000

cm: micro x 1000

How to measure cell size?

Measure using eyepiece graticule. Put minigrid in and see how many graticule units is one minigrid.

eyepiece graticule and mini grid (0.1 micrometer)

How to calculate cell size, magnification or image drawn at?

I= M times A

*make sure same units

Light microscope- how it works?

Passes beam of light through specimen and glass lend focus light bean into an image viewed by the eye.

Transmission electron Microscope- how it works (5)

1. specimen stained with metal ions

2. beam of electrons pass through specimen

3. electrons = absorbed, scattered, pass through

4. transmitted (pass through) electrons pass through magnetic lens to strike flourescent screen to create image

5. more electrons= brighter region on image (2D IMAGE)

Scanning electron microscope

1. same as TEM but beam of electrons bounce back and forth= 3D image

2. electrons hitting specimen bounce back and scatter

3. scattered caught by detector making an image

definition of resolution and relationship between resolution and details/magnification

shortest distance between two points at which they can still be distinguished as seperate points

greater resolution= smaller details seen

(normally higher magnification = less resolution)

Ultrastructure

Structures of biological specim less than 0.2 micrometers and as small as 1nm

what can each type of microscope show us?

Light: structure of cells (nucleus, cell wall, vacuole)

Electron: ultrastructure of cell (mitchochondria, details of components inside mitchochondria) + viruses

SEM: 3D

disavantages and advantages of electron microscopes compared to light

Disadv:

• black and white

• non-living or dead as viewed isnide vacuom

• takes a long time to prepare

• expensive

Adv:

• greater resolution

• greater magnification

• greater detail

• SEM: 3D

Cyrogenic electron microscopy

used to create high resolution 3D image of molecule/virus particle

• flash frozen of proteins/nucleic acids at very cold temperatures

• no ice crystals

• placed under tem

• combined computationally to make 3D image

Freeze fracture

study internal 3D structure of cell components - cell membranes

• doesn’t image actual part, instead creates replica of surface

• exposed cotated with heavy metal and acid dissolves away original biological material

Fluorescent stains (function)

• label specific molecules or cell components to determine exact location

• glow against dark background

Immunoflorescence

• fluorescent markers to antibody molecules

Cell theory

All living organisms composed of one or more cells

All cells contain; (3 structures)

1. DNA - stores and transfers information from parent to daughter cells+ control production of protein for cell function (decide)

2. cytoplasm- made out of water, contains reactants which need to water for chemical reactions

3. plasma membrane- protects cell + determines substances in and out of cell

Organelles definition + examples of organelles and not organelles

Small components of a cell that are adapted to perform specific functions

(most organelles are membrane bound)

NOT ORGANELLES: CELL WALL, CYTOSKELETON, CYTOPLASM

Centrifuge

laboratory equipment which uses cetrifugal force by spinning substances very fast to seperate components by size or densities

eg: whole cells

Ultracentriguge

• extremeley high-speed

• can seperate cell organelles

Cell fractionation

technique scientists use to seperate organelles by size

Prokarotic cells vs eukaryotic cells (difference in their parts and the organisms that have these cells)

Pro: simpler, smaller- no nucleus or membrane bound organelles + unicellular such as viruses

Parts of prokaryotic cell + function (7)

• nucleoid- single stranded dna without a membrane

• 70S ribosome- protein synthesis which mRNA passes to it

• Pilli- short hair-like structure to facilitate DNA exchange with other bacteria

• Flagella- movement

• Plasmid- smaller loop of naked DNA (may have several in cell)

• Plasma membrane- phospholipid that is selectively permeable (controls movement of substances in and out of cell)

• cell wall- protects cell and prevents from bursting

DRAW PROKARYOTIC CELL E.COLI

Eukaryotic cell (difference with pro)

• more complex

• has membrane bound organelles

• cytoplasm is compartmentalised

• has nucleus

Envelope

double membrane surrounding nucleus

Pores

Holes present in membrane to allow proteins to exit (mRNA)

function of nucleus

contains genetic material (chromosomes)+ determine what substances can enter and leave cell

chromosomes definition

tightly wound DNA that is found in nucleus

chromatin

loosely coiled DNA found in nucleus- stains dark colour, at edges of nucleus

Transcription (nucleus)

Process in nucleus where mRNA makes a copy of the nucleotide sequence of the cell

nucleolus

darker region inside nucleus where ribosomes produced

function of nucleus (2)

• contain heridetary information

• control cell activities: determine what protein to produce (gene expression)

Phospholipds

two fatty acids with a phosphate group

fatty acids: hydrophobic

phosphate group: hydrophillic

3 benefits of nucleur compartmentalisation (having an envelope)

1. protects the dna inside nucleus by seperating it from potentially harmful molecules inside cytoplasm + ensuring conitions inside nucleus is good

2. regulating gene expression- by determining entry and exit of mRNA and transcription factors, can determine what genes are on and off

3. the nucleur pores ensure that only mature mRNA can exit from the nucleus and that mRNA can leave so that protein synthesis can happen in ribosomes

how DNA codes for the production of proteins? (4)

1. DNA is transcribed (read) in the nucleus to produce mRNA

2. pre-mRNA is modified- stabilise + remove non-coding sequences

3. modified mRNA travels from nucleus to cytoplasm through pores

4. translation (reading of RNA) in ribosome

Function/ Importance of envelope (function, what would happen without + why cannot have single membrane)

• Double membrane = large nucleur pores = allows RNA, proteins to pass

• without would have to use exocytosis and endocytosis which take up alot of energy

• single would mean fatty acids that are hydrophobic would be in contact with water in the cytoplasm

Nuclear membrane during cell division (3)

1. nuclear membrane breakdown = chromosomes can interact with cytoplasm where spindle apparatus located

2. double membrane= form vesicles - float freely in middle phases

3. vesicles bind together around chromosomes (after seperation+ correctly positioned) = fuse to form new cell membrane

vesicles

small phospholipid sack formed by nucleus during cell division

compartmentalisation of organelles

organisation of cell contents into distinct regions for specialisation of function

Advantages (4) of compartmentalisation in cytoplasm of cells

1. efficiency in metabolism- enzymes and substances are localized = higher concentration = so reactions can occur quickly

2. toxic/damaging substances can be isolated (digestive enzymes that digest itself are localized)

3. localised conditions = conditions can be kept at optimal levels in each location

4. quantities and location of organelles can be changed dependent on the cell’s requirement

Function of Mitochondion (3)

produces energy through areobic respiration and is the site for ATP production

cristae + function

folds of inner membrane of mitochondria + increases surface area for atp production/ chemical reaction

matrix

dense, gel-like fluid inside mitochondrion

70 S ribosomes vs 80s ribosomes

70s: smaller (prokaryotic, mitochondria, chloroplasts)

80s: larger (eukaryotic and rough ER)

parts of mitochondria (7)

1. outer membrane

2. inner membrane

3. inter-membrane space

4. matrix

5. cristae

6. ribosomes 70s

7. loops of naked mt DNA

function of intermembrane space + what is it

space between outer membrane and inner membrane

small space= higher concentration of H ions = concentration gradient = diffusion will occur faster

diffusion

the movement of substances from an area of high concentration to lower concentration

matrix function

contains enzymes and maintains optimum pH for krebs cycle

inner membrane function (what does i contain)

contains ATP which is the ezyme for respiration

Ribosomes function

synthesise proteins

80 S ribosomes structure

two subunits attach to molecule of mRNA

how ribosomes create a protein?

They translate the sequence of bases on mRNA (from either nucleus or mtDNA in mitochondria), joining amino acids in a specific order to form protein

two locations 80S ribosomes are found:

1. floating around in the cytoplasm

2. attached to outer surface of the membranes of the rough endoplasmic reticulum (rER)

function of rER

1. bound ribosomes on surface synthesize proteins for export from the cell

2. move through cisternae through ER network

3. the rER forms vessicles which transport the proteins to the golgi apparatus

Function fo golgi apparatus

1. recieve proteins in transport vesicles from the rough endoplasmic reticulum + processes and modifies + packages into secretory vesicles for release outside of the cell

2. produces lysosomes

cisternae

sacs of flattened membrane sacs that make up golgi apparatus and rough endoplasmic reticulum

function of smooth endoplasmic reticulum

lacks ribosomes + synthesizes lipids and steroids

differences to ER: (4)

1. no ribosomes

2. close to plasma membrane

3. cisterna shorter and curved

4. structure more organised

difference between proteins coded for ribosome on rER and floating in cytoplasm

rER: proteins that are secretion/go to golgi apparatus

cytoplasm: proteins needed inside the cell

secretory vessicles

vessicles that bud off the golgi apparatus which secrete substances out of the cell (such as proteins)

exocytosis

the process of releasing substances out of the cell (extracellular release)

how do substances know to be released immediately or stored in secretory vessicles for later release?

triggered by external chemical signal ligand binding to specific receptor

ligand

a smaller molecule that binds to a larger molecule such as a protein or receptor to trigger a response

what are vesicles?

membranous sacs made of phospholipid, consists of single membrane- small in size

function of vesicles

transport/store substances between organelles (eg: rER to golgi apparatus) or to and from plasma membrane during exocytosis

what are vacuoles?

membranous sacs consisting of a single membrane with fluid inside

vacuole function

store substances

function of plant cell vacuole

sap vacuole

1. maintain turgor pressure, which is needed to provide support to plant tissues

2. stores:

• water

• sugar

• ions

• wastes

• pigments

turgor pressure - plant cells

pressure fluid inside cell exerts on plasma membrane

how are vesicles formed?

section of membrane break off or bud off

endocytosis definition

cell bringing extracellular substance into cell

How are proteins made in the cell to be released out of the cell?

1. DNA is transcribed in the nucleus to produce pre-mRNA

2. the mRNA is then modified to stablise it by removing non-coding sequences

3. the modified RNA travels through nucleus pores to cytoplsm

4. the mRNA is translated by ribosomes in the Rough Endoplasmic Reticulum

5. the subunits of ribosomes attach to the mRNA to form a single structure

6. the ribosomes translates sequences of bases in mRNA to join amino acids to form proteins (protein synthesis)

7. the proteins travel through the cisternae and the ER network

8. transported by vesicles formed by the rER to the Golgi Apparatus

9. Golgi Apparatus receives the proteins and modifies it

10. Gogi apparatus buds off and forms secretory vesicles which the proteins are packaged into

11. the secretory vessicles then either immediately release the proteins by exocytosis or store them until a ligand binds to a specific receptor

Clathrin

protein/molecule that helps form vesicles inside of cells

how are vessicles formed? (5)

1. ligand binds to receptors on membrane to signal it to form a vesicle

2. Adaptor proteins attach to receptors and recruit Clathrin molecules

3. Clathrin forms rounded 3D lattice + forcing cell membrane to bend inwards and form a bud

4. dynamin pinches of bud from cell membrane, forming vessicle

5. clathrin coat breaks apart and is recycled for reuse

phagocyte

type of white blood cell that protects body by engulfing and destroying harmful foreign particles such as bacteria/viruses

how vesicles form to remove virus particles

1. antibody molecule coating virus particle bind to receptor (ligand =antibody molecule)

2. triggers ATP proteins to recruit Clathirin

3. plasma membrane invaginate (push an outer layer or structure inward upon itself to form a pocket)

4. Clathrin molecules surround the invagination and undergo polymerisation (Clathrin molecules form lattice by interlocking with each other)

5. forms a Clathrin coated pit with the Clathrin lattice surrounding the membrane

6. Dynamin pinches of membrane to form vesicle

7. Clathrin coat breaks down into individual pieces to be reused

What are lysosomes

specialised type of vessicle - spherical with single membrane

how are lysesomes formed

budding from Golgi Apparatus

Autolysis

the breakdown of the cell itself using the digestive enzymes in a lysosomes

function of lysesome

waste disposable = to break down worn out/damaged organelles, ingested food, ingested bacteria, the cell itself through its digestive enzyme it contains

phagocyte

certain white blood cell which has the ability to engulf bacteria

how does phagocytosis work?

1. Attachment: The phagocyte (white blood cell) attaches to the pathogen (e.g. bacteria).

2. Engulfment: The phagocyte extends parts of its membrane called pseudopodia around the pathogen, engulfing it.

3. Phagosome formation: The pathogen becomes enclosed inside a membrane-bound vesicle called a phagosome.

4. Fusion: A lysosome fuses with the phagosome, forming a phagolysosome. The lysosome releases digestive enzymes into it.

5. Digestion: The digestive enzymes break down and destroy the pathogen.

6. Waste removal: Undigested material is released from the cell.

phagocytosis

process of certain white blood cells engulfing bacteria

pseudopodium

the cell membrane that surrounds the pathogen in a phagocyte

phagolysosome

part of the process of phagocytosis where the lysosome consisting the digestive enzyme and phagosome (vessicle + bacteria) is together

phagosome

membrane vesicle + pathogen, part of process of phagocytosis

phagocytic vacuole

the part of the cell that bacteria is taken into inside a phaogycte( white blood cell that engulfes bacteria)

2 types of cytoskeletons

microtubules and microfilaments

explain the structure+ made of and function microtubules

structure: cylindrical, straight and hollow

made of: tubulin protein

function:

1. provide shape and support

2. moves organelle within cells

3. form spindle apparatus

explain the structure+ made of and function Microfilaments

structure: thinner, not hollow, can be branched or unbranched

made of: actin protein

functions:

1. cleavage furrow during cytokenisis

2. cell shape

3. muscle contraction

4. cell mobility

Centrioles function, made of what, found where

ANIMAL ONLY.

• barrel shaped

• near nucleus

• made of microtubes arranged in “9+2” arrangement

function: forms spindle apparatus

what is cilia, what does it contain and function

• thin-hair like projections from cell surface

• has micotubules

• move things across

eg: ova in fallopian tube or mucus in respiratory passages

ONLY IN AMINALS

flagellum what is it, what does it contain and function?

• long, whip-like projection

• contains microtubules

• function to move cell eg: sperm cell

ONLY IN AMINALS

chloroplasts function

produce glucose through photosythesis (food for plant)

what is inside a chloroplast

1. thylakoids: stacks of membranous sacs, shaped like flattened discs

2. chlorophyll: molecules found in sacs for photosynthesis

3. stroma: dense, gel-like fluid

4. 70s ribosomes

5. lamella: connects and seperates thylakoid stacks

6. small loops of naked dna

7. starch grains: if photosynthesis is happening quikcly

8. plastids: same structure as chloroplasts but no chlorophyll

the cytoplasm of different cells

plant vacuole: cell sap

chloroplasts: stroma

cell: cytoplasm

mitochondria: matrix

chloroplast envelope and outer mitchochondria membrane function

compartmentalis