Studied by 1 personenzyme, cell theory, organelles, stem cells, cell control system, cell signaling
define an enzyme
a biological catalyst that accelerates the rate of a chemical/metabolic reaction in a living organism
is not permanently changed or consumed by the reaction it catalyzes
which types of biological molecules are enzymes
protein or rna molecules (ribozymes)
which part of the enzyme catalyzes a reaction and reduces the activation energy of that chemical reaction?
the active site
what is a catalyst
a substance that speeds up a chemical reaction
why are biological systems completely dependent on enzymes?
enzymes accelerate chemical reaction rates to enable cells to perform all their chemical reactions within a biological, useful time frame
why must your cells precisely regulate enzyme activity?
cells precisely coordinate thousands of chemical reactions simultaneously
when do your cells activate an enzyme?
when the cell needs its product
when do your cells inhibit an enzyme
when the cell doesn’t need product
why must enzyme regulation be rapidly “reversible”?
it enables cells to maintain the proper concentration of each product
describe competitive enzyme inhibition
when a regulatory molecule (inhibitor) binds to the active site and prevents the substrate from entering the active site
describe allosteric regulation by a noncompetitive inhibitor
when a regulatory molecule binds to a different site on the enzyme (allosteric site), changing the shape of the enzyme so it cannot bind to the substrate.
how does a kinase/phosphatase enzyme rapidly change the activity of other enzymes?
they remove/add a phosphate group to enzymes which changes the structure of the active site, which either stimulates or inhibits the activity of the enzyme
what is phosphorylation?
a process done by kinases in which a phosphate group is added to the amino acid of the enzyme which can either inhibit or stimulate the activity of the enzyme
what is dephosphorylation?
a process done by phosphatases in which a phosphate group is removed from the amino acid of the enzyme which can either inhibit or stimulate enzyme activity
why do some predators produce venom that contains permanent enzyme inhibitors in their prey?
the inhibitors prevent enzymes in the prey’s body to catalyze biological reactions
what are enzyme cofactors?
enzymes helpers
usually vitamins and minerals
bind to a specific location ont he enzyme to activate the active site
why must our diet contain vitamins and minerals for proper enzyme function?
without vitamins and minerals in our diet, enzymes can’t lock the substrates into the active sites which prevents reactions from taking place, causing vitamin deficiency diseases
why is each enzyme in a specific cellular location or extracellular location?
it is in the optimal position for the product that is being generated to be located
what is an example of an enzyme located in the blood?
protein kinase
what is an example of an enzyme located in the nucleus of your cells?
rna polymerase
why is the cell the most basic biological unit of life?
it is the smallest biological system that is alive due to its ability to
acquire energy and process energy independently
repair itself independently
reproduce independently
what are the 3 parts of the cell theory?
cells are the most fundamental units of life
all single cell species are composed of one cell and all multi cell species are composed of two or more cells
all cells are produced from the reproduction of a preexisting parent cell
why aren’t viruses considered the most fundamental units of life?
viruses cannot reproduce independently
how many types of chemicals potentially exist in one of your cells?
over 10^5 different types of molecules exist in a single cell
how many types of chemical reactions potentially occur in one of your cells?
over 10^6 different chemical reactions
describe the fundamental differences between the prokaryotic and eukaryotic cells
prokaryotic cells don’t have a nucleus while eukaryotic cells do have a nucleus
Which internal structures are absent in Prokaryotic Cells?
nucleus and membrane-bound organelles
which type of cell typically is larger
eukaryotic
Are there more Single-Cell Species or Multi-Cell Species on Earth?
single cell species are more abundant on earth
Why is each Organelle in a Eukaryotic Cell able to perform a unique set of cellular functions?
they contain a unique set of enzymes and other chemicals that are essential to each organelle
Why does a Eukaryotic Cell require a complete set of functional Organelles?
it is essential to function as a coherent biological system
Are the Organelles surrounded by one or more Membranes or a Protein Layer?
organelles are surrounded more one or more cellular membranes
Why is each Microcompartment in a Prokaryotic Cell able to perform a unique set of cellular functions?
they are specialized internal structures that contribute to cell function
Why does a Prokaryotic Cell require a complete set of fully-functional Microcompartments?
they make a unique set of enzymes and other chemicals
Are the Microcompartments surrounded by one or more Membranes or a Protein Layer (Shell)?
they are surrounded by a protein shell
Which types of Cells contain Organelles?
eukaryotic cells
What is the defining feature of the Eukaryotic Cell?
the presence of a nucleus
Describe why one of your Eukaryotic Cells is as “Complex as the Universe”.
there are thousands of biological chemicals, structures, and reactions that contribute to the function of a cell
Why is each Organelle in a Eukaryotic Cell able to perform a unique set of cellular functions?
each organelle contains a unique set of enzymes and chemicals that endow it with unique biochemical and cellular functions
Why does a Eukaryotic Cell require a complete set of functional organelles?
because it needs to be able to carry out its proper functions for the body
describe the cellular functions of the cytoskeleton
- determines cell shape and provides cell with physical support
- enables cell to change shape
- cell motility
- intracellular transport
- cell division
- muscle cell contraction
- attachment site for organelles and ribosomes
- adhesion to other cells and to the extracellular matrix
- enables endocytosis and exocystosis by influencing cell membrane characteristics
describe the cellular functions of chloroplast
- photosynthesis
- synthesize chlorophyll and carotenoid pigments
- use sunlight energy to make energy rich atp and nadph molecules
- convert co2 to carbohydrates
- synthesize amino acids, carbohydrates, lipids and nucleotides
- starch storage
describe the cellular functions of the endoplasmic reticulum
- folding and oligosaccharide addition to membrane proteins and secretory proteins
- increases in size to inc the production of secretory proteins
- lipid synthesis (all 3)
- attachment site for ribosomes and mitochondria
- calcium storage
- detoxification of harmful chemicals like thanol
- eliminates denatures proteins
- rough endoplasmic reticulum
- ribosomes are attached to the rough er
- smooth endoplasmic reticulum
- performs lipid synthesis and detoxifies toxins
describe the cellular functions of the golgi apparatus
attach oligosaccharides to membrane proteins and secretory proteins
sort and deliver membrane proteins and secretory proteins to the locations where their functions are needed
synthesize and deliver new cell membrane materials to the cell membrane
describe the cellular functions of the lysosome
- digestion
- autophagy (self eating) of damages and deteriorating organelles
- waste disposal
- detoxification
- contributes to apoptosis
describe the cellular functions of the mitochondrion
- cellular respiration and atp synthesis
- dna storage
- calcium storage
- steroid and heme synthesis
- apoptosis
- heat production
describe the cellular functions of the nucleus
control of the protein and enzyme synthesis.
control of cell division and cell growth.
storage of DNA, RNA and ribosome.
regulation of the transcription of the mRNA to protein.
production of ribosomes.
describe the cellular functions of the peroxisome
- metabolism
- fatty acid digestion (beta oxidation)
- amino acid catabolism
- purine catabolism
- synthesis
- phospholipid synthesis
- steroid synthesis
- heme synthesis
- detoxification
What is the source of Human Totipotent Stem Cells?
fertilized egg (zygote)
What is the unique ability of totipotent stem cells?
the ability to develop into your entire body and to develop into any of the 220 human cell types
which human cell types can be produced using totipotent stem cells?
any human cell type
which human cell types can be produced using pluripotent stem cells?
any human cell type.
which human cell types can be produced using multipotent stem cells?
can develop into a specific subset of human cell types or a single cell type
which human cell types can be produced using induced pluripotent cells (iPS)?
four genes code for proteins that reprogram the mature skin cell genome to revert to the developmental state of the pluripotent embruonic stem cells
what is the source of totipotent stem cells?
fertilized egg
what is the source of pluripotent stem cells?
human embryos at the 16-cell and 32-cell stage, placenta
blood in the umbilical cord
what is the source of iPS cells?
generated in a lab using genetic engineering technology
What are some medical uses of iPS?
- when exposed to specific signaling molecules, they can develop into clusters of cells that have similar characteristics to organs
- generate organoids
- can be used to study organ development or cancer development
- test which pharmaceuticals would be most effective
- mini tumors can be used to determine which anti cancer drug is most effective
What type of Stem Cell(s) would you use to develop a therapy that could replace any of the 220 Cell?
iPS
Why are the Pluripotent Stem Cells in the umbilical cord blood of infants collected at birth and stored?
it provides the child with a supply of their pluripotent stem cells for future medical treatments
What are the medical advantages of cord blood banking?
there is a supply of pluripotent stem cells for possible future medical treatments
What are the functions of Adult Stem Cells in the Human Body?
they can develop into a specific subset of human cell type or a single cell type
where are adult stem cells located in the body?
adipose tissue
blood vessels
bone marrow
brain
breast
eyes
hair
heart
intestine
liver
lung
muscle
olfactory mucosa
skin
teeth in dental pulp
testes
How could Adult Stem Cell Therapy improve the quality of life?
the body is completely dependent on adult stem cells as they supply the body with new cells for growth, repair, renewal and immunity
What are some potential Adult Stem Cell Therapies?
- regenerative medicine
- restoration of most cell types in the body that were lost or injured
- organ harvesting by injecting human stem cells in pigs to transfer to humans
Why is Adult Stem Cell injection into the Body a medical risk?
they could multiply abnormally and cause cancer
trigger destructive immune responses
secrete signaling molecules that can have unintended consequences
What are Organoids? What are some practical uses of Organoids?
clusters of cells that express some organ characteristics
uses
testing cancer treatments
researching tumors
Which type of Stem Cells are used to make Organoids?
induced pluripotent cells
The Adult Stem Cells are in the “Stem Cell Niches” of the Human Body. Why are the Stem Cell Niches critical to maintain proper Adult Stem Cell function?
niches contain all the physical and chemical characteristics necessary to maintain the essential properties of the adult stem cells
Why must multi-cellular organisms precisely regulate Mitotic Cell Division?
to serve the overall needs of the body- when the body needs a supply of new cells for growth, development, renewal, repair or defense
When does the Body instruct its Adult Stem Cells to divide (reproduce)?
during interphase (g1, s, g2)
when the body needs a supply of new cells for growth, development, renewal, repair or defense.
Why does the Body frequently require a supply of new Cells?
growth, development, renewal, repair or defense
what is the cell cycle?
the sequence of events an adult stem cell experiences from the time it is produced by the mitotic division of its parent cell until the time it divides to produce 2 daughter cells
what happens in the g1 phase?
commit to reproduce
begin organelle duplication
build more ribosomes to increase protein synthesis capacity
begin duplicating all proteins
synthesize deoxyribonucleotides
begin doubling in size
what happens in the s phase?
dna polymerase enzymes replicate all 46 dna molecules in the nucleus which ensures that each daughter cell inherits 46 dna molecules
what happens in the g2 phase?
makes final preparations to divide,
completes duplication of all organelles and biological molecules, including proteins
synthesize more tubulin proteins for spindle formation
repairs all injured organelles and defective biological molecules
cell size is doubled
what happens in the m-phase?
mitotic phase in which the cell reproduces and divides by mitotic cell division
what happens in the g0 phase?
occurs when the cell has exited the cell cycle and is not preparing to divide,
when the body instructs an adult stem cell int he g0 phase to re enter the cell cycle, it will enter the cycle in the g1 phase
During which Cell Cycle Phase does the Adult Stem Cell make the commitment to divide?
g1
During which Cell Cycle Phase does the Adult Stem Cell increase in size?
g1, g2
During which Cell Cycle Phase does the Adult Stem Cell replicate dna and synthesize nucleotides?
g1.
During which Cell Cycle Phase does the Adult Stem Cell duplicate its organelles?
g1, g2.
During which Cell Cycle Phase does the Adult Stem Cell makes its final preparations before dividing?
g2
During which Cell Cycle Phase does the Adult Stem Cell divide (reproduce) by mitotic cell division?
m-phase
Why must multi-cellular organisms precisely regulate Mitotic Cell Division?
to serve the overall needs of the body,
if it fails to regulate, it can result in cancer, tumors, etc
What is the function of Cell Cycle Checkpoints?
each checkpoint sensor verifies that essential cellular events were completed accurately, search for biochemical errors, advance if no errors are detected
function of the g1/s checkpoint (first checkpoint)
the cell must recognize a go-signal the body produced to pass this checkpoint and enter s phase
the g1 cyclin protein and cdc2 CDK control passage through the g1/s phase checkpoint
checks growth factors, cell size and nutrition of the cell
function of the g2/m checkpoint (2nd checkpoint)
verifies the accurate completion of dna replication (dna synthesis) during s phase and instructs the cell to advance to g2 phase
checks for dna replication completion, that chromosomes are lined in the middle, search for biomedical errors and corrects them if there are
function of the m-phase (spindle) checkpoint (third checkpoint)
prevents aneuploidy (not having 46 chromosomes) in the nucleus of each daughter cell
ensures all chromosomes are attached to the spindle before the adult stem cell can complete mitotic cell division
Do some cancer cells ignore one or more Checkpoints?
yes, therefore they can complete the cell cycle and reproduce.
How do mutations enable cancer cells to ignore one or more Checkpoints?
yes, some mutations can enable cancer cells to ignore the checkpoints, thus completing the cell cycle and multiplying
What factor would activate each Checkpoint?
cyclin dependent kinases
A Checkpoint is activated. How will the Adult Stem Cell respond after the biochemical error is repaired? What is the response if the biochemical error can’t be repaired?
after it is repaired, it will continue the cell cycle until completion. if it cannot be repaired, it will undergo apoptosis
What is the result of defective Cell Cycle Checkpoints?
cancer
What is Apoptosis? Do some mutations prevent Apoptosis in cancer cells?
apoptosis is controlled cell death
yes, come cancer cells can prevent apoptosis.
What are some types of Signals (Ligands) that your Cells must recognize?
defective human molecules
elements like calcium and sodium
food molecules
gases (O2 and CO2)
gravity
hormones
injury-related molecules
light
mechanical pressore
neurotransmitters
pH
pathogens
relative position
sound
temperature
toxins
What are Receptors?
they are proteins which bind to ligands and cause responses in the immune system
Which biological molecules serve as Receptors?
proteins and some are rna molecules (riboswitches)
What are the Major Groups of Receptors?
g protein coupled receptors (gpcr)
tyrosine kinase receptors (rtk)
histidine kinase receptors
ligand-gated ion channel receptors
riboswitches (rna molecules)
G-Protein Coupled Receptors functions
required for cell cycle regulation
immunity
sensory stimuli, hormone
neurotransmitter perception
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