fall final Flashcards
what is the fluid mosaic model?
the structure of the cell membrane
what are the 6 functions of proteins?
-maintain cell shape
-coordinate changes inside and outside the cell
-receptors for chemical messengers from other cells ;
-enzymes that catalyze reactions;
-glycoproteins are involved in cellular recognition
-the transport of substances across the membrane.
what is a selectively permeable cell?
cell mem that allows some substances to cross
more easily than others
what is diffusion?
passive transport, requires no energy, the movement of
a substance down its concentration gradient from an area of higher concentration to an area of lower concentration
what is facilitated diffusion?
passive transport of a
substance across a membrane through a specific transport protein, down its concentration gradient.
What is aquaporin?
a pore forming prtein that allows for fast diffusion
what is osmosis?
the movement of water across a sleetivly permeable mem until equalibrium
what is hypertonic?
a higher concentration outside of the cell relative to the inside of the cell (crenates, loss of water)
what is hypotonic?
lower concentration outside of the cell, relative to the inside of the cell (bloating)
what is isotonic?
the same concentration
inside and outside of the cell
Define osmoregulation
describes how cells
control this water balance to maintain homeostasis
What is active transport? where does it get its energy from? What is actually transferred to the transport protein to give it energy?
substances move against CG and require energy.
ATP supplies energy
the phospahte group in ATP is transfered to get energy
In active transport do substances move up or down their concentration gradient?
move aginst CG from low CG to high CG
what is endocytosis?
get things from the outside of the cell to the inside
plasma membrane forms a vesicle surrounding
substances on the outside of the cell and this forms a vesicle within the cell
what are the three kinds of endocytosis?
-phagocytosis; cell eating, pseudopodia creates vacuole to be digested by a lysosoome
-pintocytosis; cell drinking, not specific, create small vesicles to get fluid from extracellular matrix that is brought into cell and does not get dissolved.
-receptor mediated; very selective, coated in proteins that
specifically bind particular molecules from their surroundings, these are pinched off to form vesicles within the cytoplasm.
what are the 2 basic forms of energy?
kinetic and potenial energy.
kinetic- the energy of motion like riding a bike, heat and light as well
potential- energy that matter possesses as a result of its location or structure, energy waiting to be used, like water held back behind a dam
what is Thermodynamics?
The First Law of Thermodynamics states:
The Second Law of Thermodynamics states:
the study of energy transformations.
1- law of energy conservation, Energy can be transferred and transformed, but it cannot be created or destroyed
2- the entropy law, all things tend towards max randomness
what is the primary difference between exergonic and endergonic reactions?
exergonic- reactants contain more energy than the products and the reaction releases
energy to the environment
endergonic- create products that are higher in energy, from reactants that are lower in energy
If the energy of the products is less than the energy of the reactants, the reaction must be..
exergonic
If the energy of the products is more than the energy of the reactants, the reaction must be..
endergonic
What is metabolism?
all exergonic and endergonic reactions in the body
what is energy coupling?
he use of energy released from exergonic reactions to drive essential endergonic reactions.
What is ADP and ATP?
ATP- cell energy, made of adenine, ribose, and 3 phosphate groups
ADP- what ATP becomes after energy is released (loss of a P group)
What is phosphorylation
he transfer of a phosphate group to another molecule. This
energizes the molecule so it can be used later in cellular work.
What is the energy barrier of a chemical reaction called and what do enzymes do to this barrier?
- activation energy, the amount of energy that reactants must absorb before a chemical reaction will start
What is an active site on an enzyme? What would happen to the active site if the protein became denatured?
-The part of an enzyme where a substrate binds by groove
-stop functioning
What is a cofactor? what is a coenzyme?
- non protein molecule required for functioning of enzymes (binds to active site) like iron
- a cofactor that is organic molecule like folic acid
what is tonicity
the ability of a solution surrounding a cell to cause that cell to lose or gain water
what is exocytosis?
exporting large substances out of cell
what are competitive inhibitors?
the inhibitor binds to the active site and competes w substrate for the active site and slows rate of reaction
what are noncompetitive inhibitors?
binds to the enzyme at another location, referred to as an allosteric site so it changes the shape of the enzyme so that the
active site no longer fits the substrate
what is a proenzyme?
enzymes in the body are produced in an inactive form that eventually will be active.
protects cell from digesting itself
what is feedback inhabition?
a method of metabolic control in which the product of a metabolic pathway acts as an inhibitor of an enzyme within the pathway and shuts off its production when enough is made.
what is cellular respiration?
exergonic, a series of chemical reactions that break down glucose to produce ATP
when is a substrate oxidized?
when a substrate LOSES an electron and increases oxygen (lose H)
when is a substrate reduced?
when it GAINS electrons and H
what is a redox reaction?
a chem reaction that involves the transfer of electrons
What is NAD and what is its primary function in cellular respiration?
nicotinamide adenine dinucleotide is a
coenzyme made from vit niacin, used as an electron shuttle, accepting electrons in redox reactions and becoming reduced to NADH + H+
what is FAD?
Flavin adenine dinucleotide is another electron acceptor, becomes reduced to FADH2, so also carries/transfers 2 electrons
what is the final electron acceptor in cellular respiration?
oxygen
what are the steps in order of cell resp?
Glycolysis, pyruvate oxidation, the Citric Acid Cycle, and
Oxidative Phosphorylation
what is glycolysis?
occurs in cytoplasm and doesnt require oxygen
6 glucose is broken down to ATP
adds 2 phosphate to 6 glucose on both ends
splits glucose in half called GP3
END PRODUCTION- 2 pyruvate, 2 ATP, 2 NADH, 2 H
what is citric acid cycle?
happens in mito matrix
2 carbons enter and make citrate
NAD reduced to NADH which releases Co2
END PRODUCT- 4 Co2, 2 ATP, 6NADH, 6H, 2 FADH
what is pyuvate oxidation?
happens in mitochandrial matrix
the pyruvate formed at the end of glycolysis enters the mitochondrion and is oxidized to become Acetyl Co-enzyme A (Acetyl CoA)
END PRODUCTS- acetyl CoA - 2Co2, 2 NADH, 2 H
what is total chem outcome of cell resp? how many total electrons?
4 ATP + 10 NADH + 10 H + 2 FADH
24 electrons total
During the Citric Acid Cycle, how many NAD+ and FAD are reduced and how many ATP are made per Acetyl CoA/ glucose?
6 NADH and 2 FADH2
2 ATP
Does the citric acid cycle consume oxygen?
no
what is oxidative phosphorylation? what are the 3 proteins?
elec transport
in mito matrix
1- gets elecs from NADH and pumps them across mem against CG
3 and 4
Hydrogen ions fall down their concentration gradient through a particular enzyme that is used add a phosphate group to ADP to make ATP, what is the name of the name of this enzyme?
ATP synthase, thru process called chemiosis phosphoralyzes ADP to ATP and can generate up to 28 ATP
How many ATP can be produced every second in a working muscle cell
10 million ATP
what would happen without oxygen in cell resp?
This whole system would back up and the production of the majority of your ATP would stop – this would starve your cells of energy
How does NADH + H+ get oxidized back to NAD if there is no oxygen?
lactic acid fermentation, pyruvate is reduced to lactate (lactic acid) and can make ATP
and ethanol/Alcohol fermentation, yeasts use this as they convert pyruvate to CO2 and
ethanol to oxidize NADH
what are faculative anaerobes?
yeast, They make ATP either by fermentation or oxidative phosphorylation,
depending on whether oxygen is available or not…but will always use oxidative phosphorylation if
given the option as it releases far more ATP
what are obligat aneieorobes?
oxygen is toxic to them and they need 16x more glucose to survive
In photosynthesis carbon dioxide becomes ______ to glucose and water becomes _______ to oxygen
what about in respiration?
reduced
oxidized
glucose is oxidized to carbon dioxide and oxygen is reduced to water
what is the stroma? granum? thylakoid membrane?
-in the mito matrix
-the stacks of thylakoid mems
- help absorb sunlight in order for photosynthesis contain the chlorophyll
What are stomata and what are they for?
regulate gas exchange between the plant and environment and control of water loss
where do light dependent reactions occur in chloroplasts? calvin cycle?
- thylakoid membrane and result in light energy being converted to chemical energy with the release of oxygen
-occurs in stroma
During the light reactions oxygen is released, where does the oxygen come from?
water
The conversion of carbon dioxide into sugar during the Calvin Cycle is called what?
carbon fixation. this is the first step
does light with shorter wavelengths have more or less energy than longer wavemlengths?
shorter wavelengths have higher energy because the distance between each peak is shorter
how is the colour we see visable?
the colour is being reflected rather than being absorbed, chlorophyll looks green
because it does not absorb, but reflects green light
Where are the photosynthetic pigments, chlorophyll a and b located within the chloroplast?
a- seen as green because it absorbs purp and red
both located in the thylakoid mem
what are accessory pigments?
secondary light absorbing pigments
include carotenoids (yellow, red or purple). The most important carotenoids are B- carotene (orange) and xanthophyll (yellow).
they absorb light so they increase the range of light that can be utilised by the plant for photosynthesis.
what does it mean when an electron has been raised from a
ground state to an excited state?
When a pigment molecule absorbs a photon of light, one of its electrons jumps to an energy level further from the nucleus, increasing its potential energy
what is a photosystem?
proteins embedded in thy mem, set of light absorbing pigments and associated electron carriers
theres 2 and 1
when does photosys 1 ocur?
when an excited elec is transfered to a protein carrier which reduces NADP to NADPH
The chlorophyll a in the reaction centre of photosystem II is called what? why?
P680, because it absorbs light best at this wavelength
The chlorophyll a in the reaction centre of photosystem I is called what? why?
P700, because that is its maximum absorption wavelength
This exergonic fall
of electrons provides energy to pump H+ across the thylakoid membrane from the stroma. This H+ gradient will then be used to what?
generate ATP as the hydrogen ions flow down their gradient through an ATP synthase enzyme.
The Calvin Cycle has to turn what many times to generate one molecule of G3P
Co2
What are the three main steps in the Calvin Cycle?
-Carbon fixation (adding carbon from carbon dioxide to a 5 carbon Ribulose bisphosphate
(RuPB)
* Reduction (of 3-PGA to G3P); so G3P can be released
* Regeneration of our starting molecule –RuBP (5 3-carbon G3Ps reconfigure themselves
through a series of steps to form 3 molecules of the 5 carbon RuBP, so the cycle can begin again.
what two physical factors affect the rate of photosynthesis?
temp- lower temo is slower rate
light intensity- if the amount of light decreases the rate of photosynthesis declines
what % of the carbohydrate made by photosynthesis is consumed as fuel for cellular respiration in the plant’s own mitochondria
50%
All of the energy that we use originally came from where?
the sun
what is photosynthesis
the process where sunlight is converted into chemical energy, which is a form of potential energy that can be used later to do work by plants
what is the primary reason for CO2 levels rising?
human activities, the burning of fossil fuels
what is the carbon cycle?
CO2 is release during cellular respiration and its consumption via photosynthesis
Since the Industrial Revolution, the global average temperature has already increased by about..
2 degrees
why do we need the natural greenhouse effect?
the effect traps heat in earths atmosphere and warms with, without this earth would be very cold (-18 degrees) because of it global temp is 15 degrees
why is melting sea ice bad?
less sea ice coverage of the planet means a feedback of more heat because the suns heat is not being reflected back from the ice. this is a positive feedback loop
Over the past 800,000 years, ice core data indicate that global CO2 levels never exceeded _____ ppm, but they are now over ____ ppm
never peaked above 280 ppm. We are now over 416 ppm.
when did james hanson warm about climate change?
1988
what are tipping points
when you add a certain amount of CO2 (for example), or
cause a certain amount of change in the system, the change causes feedbacks within the system that amplify the change (positive feedback) and may cause more rapid and dramatic effect
List 10 effects of climate change
-warming temp
-glaciers melting
-shorter snow or ice months
-higher sea levels
-longer more intense heat waves
-more floods, droughts, and fires
-changes migration patterns because of the changing seasons
-more intense storms
-increased susceptibility of organisms
-changing precipitation patterns
List 3 sources of energy that do not release carbon dioxide to the atmosphere
-solar energy from sun
-wind power
-Geothermal energy from heat inside the earth
-Hydropower from flowing water.
List 5 things the average person can do to help reduce their carbon footprint
-Composting
-Eat less red meat
-plants trees
-Growing and purchasing of local food
-reduce, reuse, recycle
what is solar geoengineering? who came up w the idea?
Dr. David Keith proposed this method to help cool the planet by injecting a fine sulfur dioxide aerosol into the upper atmosphere to reflect away some of the sun’s light before it can reach the earth
what is ozone?
O3 which is oxygen found in only 2 parts of the atmosphere; the stratosphere aka ozone layer (90%) and troposphere which is where we live and breathe
it acts as UV protection
What happened when we introduced CFCs (chlorofluorocarbons) into the atmosphere?
was used in the 30s as a repelent of in fridges.
learned that it damages the ozone layer as they enter the stratosphere UV hits H and releases chlorine splitting the ozone molecule makinf oxygen and chlorine which degrades the ozone layer so it cant be made fast enough to keep up w natural degration
How is ozone formed and destroyed by UV?
O2 is hit w UV and split to O atoms, they can then bind to other O2 to make O3 making ozone
what is the montreal protocol?
a document that was signed by 197 countries in 1987, where they agreed to stop producing and using CFCs.
This was the first global treaty ever signed, and it paved the way for the action that is largely responsible for reducing damage to the ozone layer
If no action were taken to reduce CFCs, what do they think might be the current state of our ozone layer?
by 2050 we would have no ozone left
what are 2 ways to asexually reproduce?
budding- new individual grows from an outgrowths of the parent and will split off, ex is yeast
binary fission- like mitosis
what are genes?
units of hereditary information consisting of a specific sequence of DNA (or RNA in some viruses) located located on the chromosomes
What are centrioles and how are they related to centrosomes?
Each centrosome has a pair of centrioles, can-shaped structures
made of microtubules
forms base of cillia and flagella
What is a centromere? A kinetochore?
centromere- links sis chromatids and assembles kinetochore
kinetochore- protein structure that each chromatid has, allows for spindles to attach to pull apart chromosomes in cell div
In an animal cell cytokinesis occurs via…
a cleavage furrow forms and the cell pinches into two
In an plant cell cytokinesis occurs via…
cell plate, becasue they have cell walls, grows inside towards the outside until it reaches both ends of cell then cell div is complete
how many pairs of autosomes chromosomes do humans have? how many sex?
22
1
what two ways introduce genetic variability?
independent assortment- how the 23 pairs of chromosomes align and are pulled apart during metaphase 1
crossing over- the exchange of genetic material between homologous pairs in prophase 1
how many possible gametes are there per parents
over 8 mill
what is a polypoid organism?
happens when meiosis goes wrong, organism is one that has more than 2 complete sets of chromosomes. Thus, a new
species is born! Many are tetraploid – containing 4 full sets of chromosomes. This dramatically increases their
genetic variability
what is cancer?
disease of the cell cycle control sys
develops thru abnormal rapid growth of cells
what are the cancer checkpoints?
G1, G2, and mid mitosis/ m phases
what is a tumour? what is a benign tumour?
-an abnormally growing mass of body cells.
-when abnormally growing cells
remain at the original site, the lump is called a benign tumour
what is a malignant tumour? when are tumours considered cancerous?
-cancerous tumour, invades neighbouring tissues and has cells that can break away and
travel through the blood or lymphatic system and spread to other parts of the body
-cancerous when it metastizies and spreads
what are the 5 types of cancers?
Carcinomas, most common, in skin or intestine
Sarcomas, in supportive tissues like bone or cart
Leukemia and Lymphomas, blood cancer
Blastoma, cancer embryonic tissue or immature cells
how do you treat cancers that have metastisized?
chemo
angiogenesis
rapidly dividing cancer cells release factors that stimulate the formation of new blood vessels towards them
oncogene
a signle gene that causes a normal cell to become cancerous
proto-oncogene
is a normal, healthy gene that, if changed, can become a cancer-causing oncogene.
what are the 3 tumour types?
-Benign, non cancerous and dont spread
-Precancerous, may turn into cancer if not treated
-Cancerous, metastasize, cancerous
How do proto-oncogenes become oncogenes?
mutate
An error in DNA replication or recombination generates multiple copies of the gene
The proto-oncogene might be moved from its normal location in the cell’s DNA to another
location
what are tumour-suppressor genes
Cells also contain genes that inhibit cell division, prevent uncontrolled cell growth
whats the RAS gene? whats the P53 gene?
in 30% of cancers, tells cells to div when not given the code to div.
in 50% of cancers, stops cell div
what is a carcinogen? what is a mutagen?
-Cancer causing agents that alter DNA and make cells cancerous.
-substances that cause mutations. Most mutagens are carcinogens.
most potent are xrays, UV or radiation
what causes the most cancer?
tobacco
The Stem Cell Theory of Cancer
tells us that even if we physically remove or shrink the majority of a tumour with chemotherapy or radiation that the cancer may continue to come back unless we have removed these special cells
list 5 ways to reduce risk of cancer
-dont smoke
-exercise
-eat veg
-reduce sun exposure
-routine testing
what is most common cancer that leads to death?
what is the most common in women?
lung
breast
90% of Canadians who develop cancer are over the age of what
50
whats the best cancer and worst?
best- Thyroid and testicular Cancer (97%) survive
worst- Pancreas (10%) survive
what is a Character? what is a trait?
-a variable (like flower colour)
-the variant of the character (purple)
what is a Hybrid?
the offspring of two different varieties
what is an Allele?
an alternate version of a gene that resides at the same
locus on homologous chromosomes.
What were Mendel’s 4 hypotheses that he derived from all of his experiments? (pea guy)
- There are alternate versions of genes that account for variations in inherited characters
- For each character, an organism inherits 2 alleles, one from each parent which are hetero or homo
- there are dom and recessive traits and dom will always be expressed even if its only seen on one
- A sperm or egg carries only one allele for each inherited character
What is a dominant allele? Recessive?
dom- an allele that needs to be present on only one of the homo chroms to be expressed and masks the expression of other alleles
rec-allele that must be present on both chroms to be expressed
The probability that an event can
occur in two or more alternative ways is the sum of their separate probabilities
the rule of addition
Epistasis
When the expression of one gene interferes with the expression of another, ex is the labs coat colour
Incomplete dominance?
co dominence?
in- produces a mix of the two alleles, would see pink
co- express both alleles themselves, wouls see red and white
why is type O uni donor? why is AB uni receiver?
o- has no antigens so wont harm anything if added to another blood type
ab- has antigens for a and b so can accept both and o has no antigens so it can also be accepted
Pleiotropy
when a single gene affects many phenotypic characters, sickle cell
Polygenic Inheritance
occurs when multiple genes affect a single phenotypic character, skin colour.
if all genes rec, youre light, if all dom, youre dark
what is epigenetics
alterations in the genome that result in changes in gene expression that arent attributed to changes in DNA sequence, this can be caused by things like trauma or diet
what are linked genes?
Genes located close together on the chromosome
tend to be inherited together
what can turn off genes?
trauma
what is The chromosome theory of inheritance
states that genes occupy specific loci on chromosomes and it is the chromosomes that undergo segregation
and independent assortment during meiosis
what is sex-linked gene
A gene that codes for something other than sexual determination, that is on a sex chromosome,
