bio module 3 Flashcards
does cell division occur at all times? explain why yes or no
no it doesnt because uncontrolled cell division (cell division that happens all the time) is dangerous and can lead to cancer
what are cyclins?
proteins that appear and disappear repeatedly (cyclically)
what are cyclin-dependent kinases (CDK)?
enzymes that are activated by cyclins (proteins that appear and disappear cyclically)
are CDK’s (cyclin-dependent kinases) always present and running?
yes they are always present but no they are only running when activated by a cyclin protein
when does the amount of cyclin protein increase and decrease
increases: mitosis
decreases: interphase
explain the three checkpoints in the cell cycle
- before entering S phase: check if DNA is damaged
- DNA replication checkpoint at the end of G2: is all DNA replicated?
- Spindle assembly checkpoint (before anaphase): are all chromosomes attached to the spindle
what are cell membranes composed of (3 things)
lipids, proteins and carbohydrates
a selective barriers that controls the movement of molecules between the inside and the outside of the cell
the plasma membrane/ cell membrane
what organelles do the endomembrane system involve
nucleus, nuclear envelope, endoplasmic reticulum, golgi appartus, lusosomes, vesicles and plasma membrane
organelles involved in harnessing energy and likely evolved from free-living prokaryotes
mitochondria and chlroplasts
state the cell theory (3)
- all organisms are made up of cells
- all cells come from preexisting cells
- there is not life without cells (the cell is the fundamental unit of life)
what does amphipathic mean?
both hydrophilic and hydrophobic
what part of the phospholipid is hydrophilic and what part is hydrophobic
hydrophilic head, polar
hydrophobic tail, non polar
what are the four proteins in the membrane
- anchors
- transporters
- enzymes
- receptors (for da signals)
which protein is permanently stuck in the cell membrane and which is not?
integral are permanent
peripheral are temporary
diffusion moves from ________ concentration to ________ concentration
higher solute concentration to lower solute concentration
what are functinos of the golgi apparatus (3)
- to further modify proteins and lipids produced in the ER
- to sort proteins and lipids as they move to their final destinations
- to synthesize the cell’s carbohydrates
define catabolism and anabolism
Catabolism: breaking down of macromolecules into smaller units, producing ATP
Anabolism: building of macromolecules from smaller units, using ATP, cost ATP, DOES NOT PRODUCE ATP
weak bonds have _______potential energy and strong bonds have _______ potential energy and why?
more, less
because strong bonds require more energy to keep them together
because weak bonds require less energy to keep them together and therefore, more energy is stored
what are the two laws of thermodynamics?
- energy cannot be created nor destroyed
- as energy increases, entropy (amount of disorder) increases
what is our microbiome
The microbiome is the collection of all microbes, such as bacteria, fungi, viruses, and their genes, that naturally live on our bodies and inside us
what is a microbe
things that are too small to be seen with the naked eye
involve the breaking and forming of bonds
chemical reactions
describe energetic coupling
spontaneous reacrtion drives a non spontaneous reaction (ex. primary and secondary active transport)
an enzyme that is activated or inhibited when binding to another molecule changes its shape.
allosteric enzyme
what are enzymes
enzymes are proteins, biological catalysts that help speed up reactions (they increase the rate of reactions) also reduces activation energy
what are ROS
reactive oxygen species: they are unstable oxygen that causes damage to cells
the amount of energy in a system able to do work
Gibbs free energy
if we add two reactions and the resulting delta G is negative this is an example of
energetic coupling (the spontaneous reaction drives the non-spontaneous reaction)
in a reaction there is a time where old bonds are breaking and new bonds are forming, unstable, large amount of energy
transition state
cellular respiration is a set of __________ processes
catabolic (breaking into smaller compounds, we break glucose)
electron carriers accept electrons and therefore are____
reduced
what are the three phases of glycolysis?
- prepatory phase: we add 2 phosphates to glucose, we use 2 ATP
- cleavage phase: 6 carbon glucose is cut into two 3 carbon pyruvate
- payoff phase: final results: 2 ATP, 2 NADH, 2 pyruvate
what happens during pyruvate oxidation
pyruvate is oxidized
so for 1 pyruvate (3 carbon molecule): it forms 1 carbon CO2 and 2 carbon acetyl COA enzyme molecules
so for 2 pyruvate we get 2 CO2 and 2 acetyl CoA and 2 NADH
what happens in the krebs cycle
acetyl CoA (2 C) + oxaloacetate (4C) –> ciitrate 6C molecule
- acetyl CoA is the fuel molecule
RESULTS: 2 ATP, 2 FADH2, 4 CO2, 6 NADH
where does glycolysis, pyruvate oxidation, krebs and ETC happen?
glycolysis: cytoplasm
pyruvate oxidation: mitochondrial matrix
krebs: mitochondrial matrix
ETC: inner mitochondrial membrane
what is the final electron acceptor in ETC
oxygen
describe the two components of ATP synthase
The F0 subunit forms a channel (in inner mitochondrial membrane like ETC) that rotates as protons pass through it
The F1 subunit then uses this rotational energy to catalyze the synthesis of ATP
Where ATP is generated
what are the final products of the ETC in cellular respiration
28 ATP, 6 H2O
what is fermentation
fermentation is the process in which we extract energy from fuel molecules without the presence of oxygen
- do not rely on oxygen as a final electron acceptor
- instead they use organic molecules as the final electron acceptor
in lactic acid fermentation what is the final electorn acceotor
pyruvate
in ehtanol fermentation what is the final electron acceptor
acedltedhye
what are the electron donors in cellular respriation and photosynthesis
cellular respiration: NADH
Photosynthesis: H2O water!!!
where does the photosynthethic ETC happen
thylakoid membrane of chlroplast
where do the dark reactions/ calvin cycle take place?
stroma of chrlorplast
what are the inputs and outputs of the light reaction and the dark reaction
light reaction:
- input of water
- ouput of O2
dark reaction:
- input of CO2
- output of sugar
what is the photosynthetic pigment
chlorophyll
what is a reaction centre and their role
pair of chlorophyll pigments
- they change photons (light energy) into chemical energy
The regeneration phase of the Calvin cycle regnerates______ molecules of _______ from _______ molecules of ________.
3 RuBP
5
triose
can white plants perform photosynthesis
no they cannot because they lack any pigment so therefore they must use the help of fungi
what are the roles of PSII and PS1
PSII: absorbs light and then pulls electrons from water
PSI: absorbs light and produces electrons donor needed to reduce NADP+
what is the Z scheme
in the photosynthethic ETC is describes the relationship with energy between the two photosystems
what is cyclic electron transport
electrons reenter the ETC, electrons from photosystem I are redirected from ferredoxin back into the ETC
ROLE: generate more ATP
WHEN are ROS more likely to occur?
when the light density is too high
what are the two defence mechanisms to ROS?
- Antioxidants: detoxify ROS
- Xanthophylls: yellow orange pigments that convert excess light energy to heat and therefore reducing the rate at which electrons enter the ETC
what are two photosynthetic challenges
- excess light energy
- photorespiration
what is photorespiration
when rubisco binds to O2 instead of CO2 during the calvin cycle
what is a defence mechanism for photorespriation?
c4 plants increase the amount of CO2 around rubisco to increase the change of rubisco binding to CO2 rather than O2
photosynthetic effecienty
how much light is acc turned into chemical energy (max 4%)
what is horizontal gene transfer
transfer of genetic material
1) DNA transfer by conjuction: two cells closely alligned theres a bridge and DNA passed through the bride formed between the cells
2) DNA transfer by transformation: no contact, DNA released into the environment by dead cells is taken up by a recipient cell
3) DNA transfer by transduction: DNA is transferred from a donor to a recipient cell by a virus (virus transfers genetic material from one bacterium to another)
what is a harpoon DNA
a stray piece of DNA
What are the two theories of evolution of photosynthesis in eukaryotes?
- Horizontal gene transfer
- duplicarion and divergence
explain hypothesis 2 of evolution of photosynthesis
endosymbiosis: cyanobacterium was engulfed by an ancient eukaryotic cell
why does cell division occur (4 reasons)
growth, cell replacement, healing, reproduction
nondisjunction results in:
extra or missing chromosomes
why is the cell cycle regulated
so that cell division occurs only at appropriate times and places
what is cancer
cancer is uncontrolled cell division that results from mutations in genes that control cell division
What is the difference between nondisjunction I and nondisjunction II
Nondisjunction I: failure of homologous chromosomes to separate in anaphase I
Nondisjunction II: failure of sister chromtids to separate in anaphase II
what are 4 toxic mushrooms to avoid
- jack o lanterns
- death caps
- false morals
- destroying angels
what is isoleucine
isoleucine is an oxygen carrying pigment in red blood cells, a low amount of isoleucine increases lifespan and decreases chances of developing cancer
how do fungi get food?
they are heterotropic organisms, they feed by absorption
how do fungi reproduce
asexually and sexually
can fungi make their own food
no they are heterotropic
what are fungal cell walls made of
chitin (same compound found in the exoskeleton of insects)
what are filamentous fungi
multicellular strucutures with branching
true or false: yeast is an example of filementouds fungi
no they are single celled
what are mycorrhizal fungi
fungi that supply plant roots with nutrients from the soil and in return receive carbohydrates from their host
what are two challenged fungi face in completing their life cycles?
- maintaining genetic diversity
- dispersal
what does parasexual mean?
parasexual describes the crossing over process
-does not undergo meiosis
what is karyogamy?
fusion of two nuclei followed by plasmogamy
what is plasmogamy
cytoplasmic union of two cells
describes a stage in the life cycle of some fungi in which plasmogamy is not followed immediatelt by karyogamy and the cells have unfused haploid nuclei from both parents
heterokaryotic
