A2.2 Cell Structure Flashcards
Theory of spontaneaous generation
Belief that organisms could randomly appear from non-living matter
Cell theory
- smallest unit
- only arise from preexisting
all living things are made up of cells
Process of preparing wet mounts
- sharp scalpel: cut square out of onion
- tweezers: peel off thin inside layer
- transfer thin layer on glass slide
- pipette: add small drop of I2 = stain
- start cover slip at 90deg. = gently lower = avoid bubbles
- if bubbles= press w/pencil
Eyepiece garticule
Transparent ruler that is placed in eyyepiece lens to measure actual size
Light microspcope
- inexpensive
- magnifies up to 2000x
- specimens can be dead/alive
Resolution
The minimum distance between two points at which they can still be distinguished
Stage Micrometer
small, calibrated ruler mounted on stage microscope: precise distnace measurement
units of measurement
metre= 1x10^0
centimetre= 1x10^-3
millimetre= 1x10^-3
micrometre= 1x10^-6
nanometre = 10^9
Electron microscope
- expensive
- preperation of specimen is complex
- magnifies up to 500 000x
- specimen has to be dead
total magnification
ocular x objective
Cryogenic electron microscopy
- specimen is frozen
- image using computer enhancemnets (3D)
ex: virus & protein structures
Freeze Fracture
preparing sample for electron microscopy
* specimen rapidly frozen
* physically broken apart = internal structure
ex: cell membrane
Fluroscene
cells are stained with special dyes that bind to cellular components
=> UV shone
Immunofluoroscene
Antibodies combined w/dye added to specimen
=> bind to their target (UV)
Functions of Life
MR Sheng
Metabolism, Respiration, Sensitivity, Homeostasis, Excretion, Noutrition, Growth
Prokaryotes
Organisms that do not have proper nucleus enclosing their genetic material
Prokaryote contents
- nucleoid region
- ribosomes 70
- capsule
- plasmids
- pilli
- cell wall
- plasma membrane
*flagellum
Prokaryote Replication
- chromosome is replicated
- DNA copies move to opposite cell end
- cell elongates
- cell membrane grows inward = pinches off = two identical
- semi conservative replication
Eukarytotes
Organisms that contain a well defined nucleus and membrane bound cytoplasmic organelles
Eukaryote (animal) Content
- nucleolus
- nucleus
- vacuole
- Ribosome 80s
- cytoplams
- mitochondrion
- RER
- golgi.
- golgi- & vesicles
- SER
- cytoskeleton
Eukaryote (plant) Content
- same animal
+cell wall, choloroplast,
Eukaryote (fungal) Content
same animal
+Lysosomes, Peroxisome, centriole
All eukaryotes overlap
- nucleus
- vacuoles
- mitochondria
- plasma membrane
Only animal cells
- cillia
- Lysosomes
Only fugal cells
- cell wall of chitin
only plant cell
- cell wall of cellulose
- chloroplasts
- plasmids in cholorplasts
anucleate
- red blood cell= more space o2
- sieve tube in phloem= little cytoplasm&few organisms= less flow resistance
multinucleate
- skeleton muscle = small fused myocytes
- aseperate fungi= no septum
Paramecium
eukaryotic organisms that live in freshwater environments
* heterotroph = eat other organisms
* moves through cillia
* cytoplasm = dissolved enzymes
* growth until max SA:volume
* contractile vacuole: homeostasis
* asexual reproduction
micro nutrients, cytoplasm, vacuole, membrane, gullet & food vacuole
Chlamydomonas
eukaryotic organisms that live in soil, freshwater, ocean, mountaintops
* autotroph = photosynthesis
* dissolved enzymes
* light sensitive eyespot = move flagella
* growth til max = split = reproduce
* contractile vacuole
eyespot, starch grains, chloroplasts, mitocondrion, flagellum
SA:V
- as cell grows: SA:V decreases
- to increase: everything is made up of small cells
- maintain transport rates
Luis pasteaur - chicken broth
non broken swan neck
=> clear, microbes from air trapped in curve
broken
=> cloudy, microbes enter form air = multiply
tilted
=> cloudy, microbes caame from curve of tube
Endosymbiosis
- mitochondria & chloroplasts = prokaryote size
- double membrane; inner= eaten cell, outer= vesicle cell was talen into
- have naked DNA like prokaryotes
- divide by binary fission
- susceptible to antibiotics affecting prokaryotes
=> proves another cell engulfed = grew like that
cell aggregation
process by which cells come together to fomr a group cluster
* group protection
* differentiation over time
cell differentiation
turning on of genes necessary for function of specialised cell
=> normal cell splits, then gene expressed
- grouped = tisue
- organs are formed from multiple tissue
- organs interact = organ system
carry out life functions
Ribosome 70s
- in prokaryotes
- smaller then euk
- have small + big subunit
- do protein synthesis
Ribosome 80’s
- larger & higher mass
- 2 subunits
- euk.
- protein synthesis
- attached & free floating
capsule
- hydrated polysaccharide complex
- covers outermost part of cell wall
- keeps phagocytes from ingesting & destroying
nucleoid region
- prok.
- DNA structure same as euk.
- DNA packaged differently = supercoiled chrome.
- genes grouped into operons = clusteres that switch on & off
- plasmids
- naked DNA
Pilli
- protein fillament
- helps adhesion
- helps transfer DNA
Flagellum
does locomotion
Plasmids
- small circular DNA
- horizontal gene transfer
Plasma membrane
- seperates in- & exterior
- controls what goes in & out of cell
cell wall
- made of peptoglycan = polymer from AA & sugar (prok.)
- made of cellulose (plant)
nucleolus
- within nucleus
- makes RNA = ribosomes
nucleus contents
- chromatin
- DNA & protein
vacuole
helps maintain osmotic balance
vesicle
- small sac
- transports & releases susbstances produced in cell
- fuses with membrane
mitochondrion
- double membrane
- converts glucose to ATP
- has own DNA
nuclear envelop
- membrane of nucleus
- has pores, double membrane
- has nucleoplasm
RER
- produces extracellular proteins
- stack of membrane flattened sacs
Golgi app.
- processes & packages proteins
- released in golgi vesicles
cytoskeleton
- system of protein fibres
- helps maintain structure
cytoplasm
- water based- jelly like fluid
- site of metabolic reactions
centriole
- barrel shaped
- helps organise microtubuli
cytoplasm (plant)
contains cytosol = maintains turgidy
chloroplasts
- double membrane
- convert light energy -> chemical energy
- plastid
SER
- makes phosphpolipids
- produces sex chromosomes
- detoxifies drug in liver
- stores calcium ions
- helps liver release glucose
Lysosomes
- spherical sacs; membrane
- specialised vesicle
- powerful hydrolytic digestive enzyme
cell wall (fungi)
made of chitin
unicellular
single celled
=> carry out all life processes within themselves
