Ib bio unit 1 Flashcards
what is the cell theory/what are the rules?
- all living things are composed of cells
- cells are the smallest unit of life
- cells come from pre-existing cells
what are three exceptions of the cell theory and why?
- straited muscle- type of tissue used to change positions of our bodies(made out of muscle fibres)
-fibres are atypical and much larger than most animal cells(length is 30mm, normal cells usually
0.3)
-instead of having one single nucleus, they have several hundred in one cell - aspetate fungal hyphae-consist of thread like structures(called hyphae)
-no such thing as septa(divides the nuclei or hyphae)
- this causes the organism to work as a whole as there are many nuclei working together as one instead of seperatly divided. - giant algae-organisms fed by photosynthesis
-larger in size while only having one nucleus
What’s the 7 functions of life needed for a unicellular organism to survive and what do they do?
nutrition: obtains food + provides energy needed to grow
metabolism: chemical reactions in the cell to release energy
growth: an irreversible increase in size
response: the ablility to react to changes in the environment
excretion: getting rid of waste products of the metabolism
hemeostasis: the need to maintain a steady system
reproduction: producing offspring either asexually or sexually
What are stem cells?
- are cells we have that are able to become any type of cell cuz there not specialized
-big in researching cuz they can help repair broken limbs, tissues, etc.. - there are two types of stem cells (embryonic + adult)
-embryonic: unpsecialized cell that can turn into any type of cell
-adult: similar to embryonic just cannot turn into any type of cell
-there are lots of ethical and social concerns with this
Regarding functions of life, what is division of labour?
-a group of cells that has one specific job
eg. cells that are only responsible for the lungs or stomach, etc…
what is the formula to find the actual size of an organism after seeing it under a microscope?
magnification= size of image/actual size of specimen
Cell differentiation
-specialized tissues that can develop by cell differentiation in multicellular organisms
- this is because m.c. Organisms have properties that emerges from the interaction of there cellular components
What are prokaryotic cells?
-they have a simpler cel structure + no compartments
-does not have a nucleus
-mostly small in size
-found almost everywhere (water,soil,our skin,etc…)
Describe the structure of a prokaryotic cell and list out the 9 key parts of the cell
-simple structure
-does not have a nucleas
-has cel wall outside the cell membrane (much thicker and stronger as it protects the cell from bursting)
-since there is no nucleas, the cytoplasm entirely fills the cell
-cell membrane
-nucleoid region
-cytoplasm
-ribisome
-plasmid
-cell wall
-pili
-capsule
-flagellum
Describe the functions of the 9 key parts of a prokaryotic cell
Cell membrane
-regulates what goes in + out of the cell
Nucleiod region
-DNA with ends that come together to form a circle and is NOT wrapped around proteins also called (naked DNA)
Cytoplasm
-gell-like fluids (which is mostly water with dissolved molecules) this is the site of metabolic reactions occur
Ribisome
-where proteins are assembled (70s)
Plasmid
-small circular extra peices of DNA that can be shared between bacteria often confer antibiotic resistance
Cell wall
-rigid structure that gives cell shape and allows the cell to resist turbot pressure w out it bursting
Pili
-enables bacteria to attach to surfaces + transfer DNA (plasmid)
Capsule
-helps prevent dehydration and helps the cell stick to surfaces
Flagellum
-used for locomotion (the act or ability to transport itself)
What is Binary fission
-Binary fission is a form of asexual reproduction
-offspring arise from a single parents
-offspring are genetically identical to the parent
-prokaryotes use it
The process of binary fission in a prokaryote?
1) the bacterium before binary fission is the dna tightly coiled
2) the dna of the bacterium has replicated
3) the dna is pulled to the opposite poles of the bacterium as its increasing size to prepare for splitting
4) the growth of a new cell membrane+ cell wall begins the separation of bacterium
5) the new cell membrane and cells all fully develops, resulting in the complete split of bacterium
6) the new daughter cells have tightly coiled dna, ribisomes, and plasmids
What are eukaryotic cells
-has membrane surrounding their dna/genetic material
-are much more compartmentalized into organelles that have specific roles
-this is an advantage as it allows for the specialization of functions w out interface w other functions and enzymes + substances can be more concentrated then if they were spread out in the cytoplasm in prokaryotes
Examples of eukaryotes?
Protista, fungi, plantae, animalia
What is the structure of a eukaryote?
Plasma membrane; is semipermeable, which allows ut to regulate what gets in + out of the cell
-its fluid allows vesicles to pinch off and fuse w it
-includes phospholipids, integral proteins, peripheral proteins, cholesterol, glycolipids
-the smaller+less charged smt is the easier it is to pass through the phosphobilyaer
-cholestral helps stabilize the membrane and what can pass thru it
-proteins helps transport materials across the membrane
-carbohydrates helps w the cell id. eg. Blood types
Mitochondria
-site of cellular respiration which produces ATP
-has double membrane
Ribisomes
-site of protein synthesis(eg.where they make proteins+instructions from dna)
-much smaller than other organelles
-found in cystol
RER
-an extension of the outer layer of nuclear membrane
-has ribisomes attached to give “rough” look
-these ribisomes produce proteins for membranes, lysosomes, or to be secreted
SER
-no ribisomes attached
-produces phospholipids and cholesterol for cell membrane
Golgi apparatus
-series of vesicles and folded membranes located near the cell membrane
-its job is to receive, modify, and pack products from RER into vesicles for lysommes, plasma membrane, secretion out of the cell
What are the two classes of membrane proteins?
Integral and peripheral
What are the differences between integral and peripheral proteins?
Integral; permanent part of the membrane
Peripheral; not permanent and attached only temporarily to the cell membrane
What are the different membrane proteins?
Receptor proteins, recognition proteins, enzyme proteins, adhesion proteins, channel proteins, and pump proteins
What are the roles of a receptor protein?
Receptor proteins *integral or peripheral
-receives signal from, outside the cell (eg.hormones) that caused a change inside the cell
1) a messenger molecule binds to the receptor proteins
2) messenger molecule binding activates the receptor proteins, then changing its shape
3) the activated receptor protein stimulates a response in the cell]
Example; insulin receptor
-Insulin is required when blood sugar levels are high and glucose needs to be taken in by cells in the liver
-Insulin will bind to receptors on surface of liver cells, causing glucose transporter proteins to open
- this allows glucose to enter the cell
Enzyme proteins
-ATP synthase is an example of an enzyme protein
-it provides energy
Adhesion proteins
-anchors the cell membrane to the inner part
-helps support the membrane
*can be integral peripheral
Example; blood clotting process- helps to bind collagen in the blood to begin the clotting process
Recognition proteins
-acts as an identification tag on the cells surface
-it allows body cells to recognize each other as “self” instead of “invader”
-may be referred to antigens
*integral or peripheral
Channel proteins
-acts as tunnel for larger or hydrophilic molecules to be transported in/out of the membrane
-may also be carrier proteins
-always works w conc. proteins
-channel proteins functions passively (no energy required)
*integral
Example; glucose channel proteins
-allows glucose to enter cell
-glucose is too large and hydrophytllic to fit thu bilayer
-glucose needs channel protein to do this
-acts passively no energy required cuz moving from high to low conc gradient
Pump proteins
-act as tunnels for large hydrophilic molecules to be transported in/out of membrane
-function actively
-work against conc. gradient
*all are integral
Example; sodium pump
-sp binds w three s ions + a molecule of ATP
-splitting of ATP gives the channel the energy to change shape of channel
-s ions released to the outside of membrane and the new shape of the channel allows two new potassium ions to bind
-release of the phosphate allows the channel to revert to original form then releasing p ions to inside of membrane
Endosymbiotic theory process
-organelles such as chloroplast and mitochondria used to be there own independent cell becuase they have there own dna + ribisomes, etc… and then evolves to prokaryotes and eukaryotes
In the context of origins of cells, what are the mitochondria and chloroplast believed to have originated by?
Both chloroplast + mitochondria are believed to have originated when a larger cell engulfed a smaller cell by endocytosis
What is spontaneous generation therory?
-the production of living organisms from non-living matter
-eg. Maggots appear in meat
Francesco redis expriment and summary
Bot 1- meat in open flask (maggots appeared after mosquitos showed up)
Bot 2- put meat in closed flask and no maggots appeared and no mosquitos
Bot 3- put meat in open flask w cloth on top (mosq appeared on top and maggots on top of cloth where mosq were but nothing in the meat)
Pasteurs swan neck flask expriment
Flask 1- soup and no signs of growth/bacteria
Flask 2- neck of flask was broken causing air and bacteria to get inside
Summary: although air could enter the flask the bacteria present was trapped at the curve of the enck
Conclusion: if spontaneous generation was true then the soup would’ve gotten the bacterium even with the first flas expriment
what are the the four processes required for the first cell to arise? (SASP)
- Synthesis of simple organic molecules
- Assembly of organic molecules into polymers
3.self replication of some polymers - Packaging of molecules to membranes
(Basic organic molecules could form in the early atmosphere including amino acids, fatty acids, nitrogenous bases, and sugars)
+
(Basic molecules form complex polymers that includes RNA nucleotides to RNA strands)
+(self-replicating molecules evolved and become common includes RNA)
+
(Membrane form around these bilayers)
Which type of prokaryote was taken in first; mitochondria or chloroplast? Why?
-the mitochondria was taken in first
-cuz all eukaryotic cells have mitochondria, but only the plants have chloroplasts
Evidence for the claim; synthesis of simple organic molecules from non-organic molecules
Claim: simple organic molecules are the basis of more complex molec. In living things so they would have needed to arise more first
Evidence:miller and urey showed the early atmosphere has the ingredients to form these compounds spontaneously
Reasoning: simple substances must appear before more complex
Evidence for the claim; assembly of organic molecules into polymers (polymerization)
Claim: Complex organic molecules are the basis of life; proteins, nucleotides, fatty acids, and sugars that carry out the functions of life
Evidence: all living things store the same basic plan; DNA stores info and proteins carry out those functions
Reasoning: LUCA must have been made of these molecules
Evidence for the claim; self replication of some of those polymers
Claim: life must be able to reproduce (7 characteristics)
Evidence: all known forms of life are self-replicating and the first living things must’ve also been
Reasoning: if life couldn’t replicate it would not persist as it has
Evidence for claim; packaging of molecules into membranes
Claim: a membrane would sorround the polymers and self-replicating molecules
Evidence: all cells require we a membrane to separate the interior form the exterior
Reasoning: the membrane is only “useful” once the polymers and self-replicating molecules exist
Why do cells divide?
-to replace old cells
-apart of the cell cycle
-allows for more cell differentiation
In summary, any time new cells are required, mitosis is required. What does GATE stand for in this context?
G rowth- MC increase size by number of cells thru mitosis
A sexual reproduction- certain euk organisms may produce asexually by mitosis
T issue repair- damaged tissue can recover by replacing dead or damaged cells
E embryonic development- a zygote will undergo mitosis and differentiation into an embryo
Why does zygote undergoe meiosis and not mitosis.
-to produce haploid nuclei (sex cells)
How do you calculate the myotonic index?
MI= number of cells in mitosis/total number of cells x100
Why would one want to calculate a myotonic index?
-good for directing cancer cuz you can see the uncontrolled cell division
Interphase
1) G1: increase the volume of cytoplasm
-organelles are produced
-proteins are synthesized
2) S (sythensis): DNA replication
3) G2: increase the volume of cytoplasm
-organelles produced
-proteins are synthesized
When the cell carries out its normal functions… MR.POD
Metabolic reactions- necessary for the life of the cell (eg. Respiration to produce ATP)
Protein synthesisl: protein enzymes necessary to allow the cell to grow
Organelles numbers are increased- support the enlarged cell
DNA is replicated- to ensure a second copy is available to enable mitosis
Prophase
1) DNA supercoils: chromatin condenses and becomes sister chromatids
2) the nuclear membrane: broken down and disappears
3) centrosomes: move to opposite poles of cell and spindle fibres begin to form between them
Metaphase
1) spindle fibres attach to centrometre of each pair of sister chromatids
2) contraction of microtubule spindle fibres cuz the sister chromatids line up along centre of cell
Anaphase
1) continued contraction of microtubule spindle fingered that caused separation of the sister chromatids
2) after separation are now referred to as chromosomes
3) chromosomes move to the opposite poles of the cell
Telephase
1) chromosomes uncoil + d’émondeuse to chromatin
2) chromosomes arrive at poles
3) microtubule spindle fibres disappear
4) now nuclear membranes reform around each set of chromosomes
5) now cytokinesis begins (the cytoplasm + organelles divide)
Cytokinesis
-division of cell into two daughter cells
-this occurs during telephase
Process:
-a ring of contractile protein (micro filaments) is formed
-inside the plasma membrane the micro filaments pull at the equator that opulent the plasma membrane
-inward pull produces cleavage furor
-then this creates two separate cells
Cytokinesis in plants
-during telephase, membrane enclosed vesicles directed form, the Golgi. A. Migrate to the centre of cell
-vesicles fuse together to fuse tubular structures
-tubular structures merge to form two layers of plasma membrane (ie. cell plate)
-the cell plate continues to develop until it connect w existing cells
-completes the division of cytoplasm and formation of two daughter cells
Why are the cells still technically together after cytokinesis in plants?
-to maintain plant structure
-we dont need that cuz we have bones and tissue to hold us together
What are cyclins
family of proteins that control the progression of cells thru the cell cycle
What is a centrometere
-part of chromosomes that links sister chromatin
Sister chromatids
Duplicated chromosomes attached by centrometere (after anaphase when they separate called chromosomes)
What are centrioles
hold together spindle fibres
What are spindle microtubules
-Spindle fibres
-aggregates that move chromosomes around during cell division
osmosis
- may occur when there is a partially membrane
-when a cell is submerged in water, the water molecules pass thru the cell membrane from an area of low solute conc. (From outside the cell) to one of the high solute conc. 8inside the cell)
Aquaporin
An integral protein that acts as a pore in the membrane that speeds the movement of water molecules
What’s the importance of osmotic control?
-water makes solution in your cell more diluted and balanced
Hypotonic solution
Solute conc is higher inside causing H2O to move inwards to balance(osmosis)
-cell gets inflated and may burst
(Lyses)
(Normal state in plant cells)
Isotonic solution
H20 and solute conc. Is balanced in and out of cell
(Normal)
Hypertonic solution
Solute conc. Higher on the outside so H2O goes to outside leaving the cell dehydrated and deflated
(Shriveled)
What is Active transport
-typically transports material against/up conc gradient
-neurons in cell that send signals thru the body extremely quickly (to do so they depend on the conc of K+ and Na+ and this is referred to membrane potential cuz it has the potential to work)
What is resting state, depolirization, and repolirizatrion in active transport?
- Resting state
-at rest the inside of neutron has high conc. Of K+ and low of Na+ - depolirization
-when signals travel down a neutron called depolizrioation the ions are permitted by ion channels to flow across the membrane - Repolirization
-the K=/Na+ conc must be restablished
-this is done by sodium-potassium pump
Polar heads
Attracted to other polar (charged molecules)
Non polar tails
Will repel any charged molecule therefore preventing passage of ions thru the membrane
Endocytosis
(Large molecules)
-takes in extra cellular material
Exocytosis
(Bulk transport)
-expels material
Cylcin D
Triggers cells to move from G0 to G1 and G11 into S phase
Cyclin E
Prepares the cell for DNA replication in S phase
Cyclin A
Activates DNA replication inside the nculeas during S phase
Cylcin B
Promotes the assembly if the mitosis spindle and other tasks in the cytoplasm to prepare for mitosis
What are the advantages of a eukaryotic cells structure?
-enzymes can be more concentrated cuz there compartmentalized instead of being spread through the cytoplasm
-if a part of the cell gets damaged, it is likely to stay there, and not hurt the entire cell
-PH levels are maintained better
-organelles with their content can be moved around within the cell
Are integral proteins hydrophobic or hydrophilic
Hydrophobic
Are peripheral proteins hydrophobic or hydrophilic
Hydrophilic
What is the most important purpose of cholesterol in the cell?
-to control the fluidity inside the cell
If there’s too much, it would control less what could pass through
If there’s too little, it could restrict too much what could pass through
