1.1 Introduction to Cells Flashcards
Cell Theory
Theory says
1) all organisms are composed of cells
2) cells are the smallest independent unit of life
3) all cells come from preexisting cells
Centi
Metric Prefix 1/100th
Differentiation
The alteration of a cell’s morphology and physiology through changes in gene expression
Morphology
The study of living organisms and their relationships between their structures
Disrepancies/Exceptions to the cell theory (ODD CELLS)
1) Skeletal Muscle
2) Giant ALgae
3) Aspetate Fungi
Skeletal Muscle
- Made from muscle fibres.
- Like other cells these fibres are enclosed inside a membrane
- they are bigger than most cells, and have 100s of nuclei
Giant Algae
Can grow to the length of 100mm, and have only one nucleus
-long stalk
- top umperella
-bottom rhizoid
Because they are so big expected to have many small cells, but it has a single cell nucleus
Aseptate Fungi
It consists of thread like structures called hyphae.
Hyphae not divided up into subunits containing a single nucleus.
In the Aseptate Fungi there are long undivided section of hypha which have many hyphae.
Cytoplasm is continous along hyphae
Cell wals are made from chitin not cellulose.
VERY BIG, MANY MANY NUCLEI
What should you have when you draw?
a) Sharp pencil
2) Ruler, straight edge,
c) drawn to scale
How should you draw circular.rectangular objects?
closed from all sides, and smooth lines
How should you label a diagram?
Labeling should be using a RULER, straight lines
Catalyze
cause or accelerate
Unicelluar Organisms
Organism that consists of only one cell
Give 3 examples of Unicelluar Organisms
a) paramesium
b) algae
c) Bacteria
d) fungi
Multicelluar
Many cells
ALL CELLS SHARE IN COMMON: EVERY CELL
- is surrounded by a memebrane which seperates the cell contents from everything
- cells contain genetic materia, which store all the instructions for cell
- cell activities are chemical reactions catalyzed by enzymes from cell.
- Cells have their own energy relesase system (Excertion)
7 Functions of Unicelluar organisms
NMG RHER! #fablife
1) Nutrition
- obtaining food to provide energy for growth materials
2) Metabolism
chemical reaction in cell respiration to release energy
Growth
irreversable size increase
Response
ability to react to change of enviornment
React to stimuli
be able to move or see when seeing light or touching a solid.
Homeostatis
keeping conditions inside organism within tolerable limits
Excretion
Getting rid of waste from metabolism
Reproduction
Reproducing asexually to make an offspring
Asexually
Reproudcing genetically identical offspring from parents.
through binary fission.
Surface Area to volume ratio In Unicelluar organisms
If Ratio to small = substance will enter slowly and waste accumilates
Heat Production and Loss in uncelluar
If Ratio to small = cells overheat due to metablosm produced hear faster than it lost
Cell Differentiation
A multi celluar organism each cell has the full genome so it has the instructions to develop into any type of cell. During differentation a cell uses only the genes that it needs to follow a pathway of developement.
Gene Expression
Although many cell types, they have the same genes. When a gene is being used in a cell it is being expressed. The gene is switched on and information is used to make protein. This happens because of different sequences is expressed in different cell tyes.
Stem Cells
Cells that have the capacity to divide and to differntiate along different pathyways.
UNDIFFERENTIATED
ABILITY TO DIVIDE
Where do stem Cells begin?
In the human embryo. they are consistently stem cells in early stages, but gradually commit themselves to a pattern of differentiation.
Surface area to volume ratio
A variable that decreases as cells grow, so that it sets a limit to the size of cells.
System
A level of organization that emerges due to the interaction of elements.
Stargardt’s disease
A degenerative eye disease that has been the target of stem cell therapy.
Emergent property
A property of a system that emerges from the interaction of the elements of the system, where the whole is more complex than the sum of its parts.
Zygote
A eukaryotic cell fromed by a fertilization event between 2 gametes
Gamete
A mature male haploid or femal germ cell that is able to unite with the opposite sex to make a zygote
Genome
Combo of the DNA in each gamete. Contains all genetic information
Embryo
Zygote divited to 2 cells then 3,8,16…
THey divide to can create tissue
STEM CELLS DONT DIFFERENTIATE TOTIPOTENT
DONT U FORGET
STEM CELLS DONT DIFFERENTIATE TOTIPOTENT
Embryonic Stem Cells
Potentially useful for rengerate tissue (SUNBURNS),healing diseases where cells have been lost or malfunctioning, (DIABETES TYPE 1)
Uses of Embroynic stem cells
a) sunburns
b) diabeletes type 1
c) Stagardt;s disease - recessive mutation in the retina which is membrane protien used , to active transport in retina to malfunction so the patient loses vision gradually.
d) Leukemia - ABnormal white blood cells are made in bone marrow.
Name 3 sources of stem cells
1) Embryo - fertiliszing eggcels with sperm until zygote divides to many cells
2) blood extracted from Umbilical cord of baby and stem cells can be taken, frozen to use in future
3) Bone Marrow , adult tissues
Ethics of Embroynic stem cell (PROS VS. CONS)
PROS:
- Unlimited growth
- differentiate to any type
- Less chance of genetic damage to to accumiliation of mutations than adult
- genetically different from adult patient recieving the tissue
CONS:
Risk of becoming a tumor
Removal of cells from embryo kills it unless 1-2 are taken
Ethics of Blood Umbilical Cord stem cell (PROS VS. CONS)
- easy to take and store
- commercial collection and stoarge services avaialbe
compatiable with tissues of adult
Umbilical Cord is discarded anyways
CONS:
Limited quantites of stemm cells from 1 baby’s cord
limited capacity to differntiate to different cell types
Ethics of Bone Marrow stem cell (PROS VS. CONS)
PROS:
- Fully compatiable with adult’s tissues
- Removal of stemcells doesn’t kill adult
- Less chance of infectious tumors
CONS:
Less growth potential than embryonic stem cells
Hard to have as theres very burried deep into tissues
LIGHT MICTROSCOPE
PICTURES
Micrograph
Picture taken down a microscope
Our school light microscope has 3 magnifications
40x (low power)
100x (medium power)
400x (high power)
Magnification of Micrograph Formula
Size of Image/Actual Size of specimen (HAVE THE SAME UNITS ABOVE AND BELOW)
TRIANGLE
- SIze *
/ Magnification Real Speci /
SIZE UNITS Start with Meters
1 METER (M) = 100 cm
1 CENTI METER (CM) = 10mm
1 MILIMETER (MM)= 1,000 MICRO METERS (um)
1 MICROMETER (UM) = 1,000 nanometers
Electron Microscope
Microscope with a much higher resolution
highest magnification
x500,000
2 types of electron microscopes
- scanner electron microscope- makes an impage of surfaces of structures
- Transmission electron microscope - used to view ultra thin sections
Ultra Structure
Detailed structure of the cell by electron microscope
Ultra Structure of Palisade cells
Chloroplast - carriest out photosythesis
Cell wall - protects the cell
Plasma membrane - controls entry, exit of substances
Free Ribosomes sythesize cytoplasmic protiens
Nucleur membrane - protects chromosomes
Diploid
Diploid is a cell or organism that has paired chromosomes, one from each parent.
When fertilized can become anything
Why are cells small?
Shorter pathways for molecules to travel in/out of cell
Concentration gradients are easier to gradient makes diffusion efficient
Diffusion
Passive moevent of molecules from an area of high concentration to low concentration, (no energy needed from cell)
Resolution
Shortest distance where 2 points can be distinguished
4 stages of stem cells
Totipotent - can differentiate into any cell in embryo
Pluripotent - Embry delevoped, loses ability to differentiate into some cells
Multiopotent - becomes very limited to differentiate
Unipotent: Can regerate but only differntiate into their accociated cell types
