Cell as the Basis of Life A2.2 (Cell Structures) Flashcards
Outline the three basic tenets of the cell theory
1.) All living things are composed of cells
2.) The cell is the basic unit of life
3.) Cells come from preexisting cells
Outline the reason why the cell is the basic unit of life.
Smallest structural unit that is capable of using energy to sustain itself in a highly ordered state
Outline the reason why we have multiple types of cells for multi-cellular organisms
it’s specialization (for efficiency)
Outline the evidences for the basic tenets of the cell theory
Cell’s the basic unit of life: plants, animals, fungi, protists, bacteria contained at least one or more cell
All living things composed of cells: Subcellular components do not perform the same processes as full cells
All cells came from pre-existing cells: No evidence of spontaneous generation
Outline the type of reasoning that uses specific (observation) -> general conclusion
Inductive reasoning
Outline what we mean when we say deductive reasoning
General premises -> specific conclusion
(e.g. using cell theory tenets to make a specific conclusion)
Define theory in daily usage
A guess — has doubt
Define theory in scientific usage
Shown true through repeated observations and experiments, STILL CAN BE QUESTIONED BTW, just no current doubt (but has a degree of uncertainty??)
Define “well substantiated”
Lots of evidence
Define “based on a body of facts”
not opinion
Define “through observation and experiment”
Rigorous testing and use of scientific method
If given a picture, outline which formula would you use for Magnitude
M = I/A
Outline why HP and LP are relative?
Due to the given.
Outline what is considered as an image.
The actual size but magnified for us to see w/ or w/o a microscope
e.g.: what we see using a microscope, drawings, our rulers (because how can we measure the actual size using a ruler only when the organisms we study are usually tiny?), etc.
How should scientific names be written
-If written, underlined
-If typed, italicized
- The genus name should be capitalized
(e.g. Allium cepa)
Describe the methods of determining the field of view diameter (FOV) using a ruler
Method 1: Place a transparent metric ruler
Outline the two types of cells.
There’s eukaryotic and prokaryotic
List the common structures of all cells
- Plasma membrane
- Cytoplasm
- DNA
- Ribosomes
Describe the plasma membrane
It is a bilayer formed from phospholipids
- Due to their amphipathic nature (hydrophilic and hydrophobic)
Describe what a cytosol is.
It is the liquid part of the cytoplasm.
- Gel-like fluid substance made of water and many dissolved solutes (sugars, amino acids, proteins …)
What does the scale bar refer to?
Image size
Give the parts of the microscope
Outline the process of preparing a wet mount
Define staining and give examples
Define “resolution”
Smallest interval distinguishable by the microscope — level of detail visible in an image created by the instrument
Outline the benefits of a compound light microscope
- Ease of use
- Less expensive to buy
- Can observe dead or living cells in color
- Cell movement can be studied
- Quick specimen prep (minutes to hours)
What does a compound light microscope do to magnify images?
Bend light
What does an electron microscope do to magnify images?
Use electron beams focused by electron magnets to magnify and resolve
Outline the disadvantages of a compound light microscope
- Maximum magnification of 1500X (can only see bacteria)
- low resolving power (0.25 micrometer to 0.3 micrometer)
- low level of detail and smaller image size
Define begets
Gives rise to
Outline the structures common to all cells:
- Plasma membrane
- Cytoplasm
- DNA
- Ribosomes
Give what carrier of genetic information do living things use today
DNA
Describe the functions and sizes of ribosomes in BOTH prokaryotes and eukaryotes
- Catalyzes the synthesis of polypeptides during translation
- Composed of two subunits that come together to form a functioning structure
- size of eukaryote ribosomes (80s) > size of prokaryote ribosomes (70S)
Distinguish the features of a prokaryotic cell from a eukaryotic cell. (SEP AFTER)
S(ize), M(embrane)o(rganelles), R(eproduction), C(ell) w(all), D(NA) l(ocation), M(ovement) F(lagella), D(NA) P(roteins), R(ibosomes), P(lasmids), U(ni-) M(ulti-)
S, Mo, R, Cw, Dl, Mf, Dp, R, P, U/M
Smart Moms rearing cutware Delicious Mof Deplacement Reception Poetic United/Multiple
Outline and describe the structures of the prokaryotic cell and its functions
Define and explain nucleoid
Prokaryotic
Define what we mean when we say that prokaryotic cell DNA is “naked”
DNA is not associated with proteins.
In eukaryotes, how does the DNA “associate itself with proteins?
Via nucleosomes
- which is when DNA coiled around proteins called histones.
(This doesn’t happen in prokaryotic cells as they are “naked”, they don’t have membrane and thus have no “histones”/protein to coil around in)
Identify the nucleoid, cell wall and plasma membrane of this prokaryotic cell
Outline the common structures of Eukaryotic cells (not necessarily seen in both plant and animal cells)
Describe the nucleus (eukaryotic cell as nucleoid is for prokaryotic)
- Contains DNA
- Contains nucleolus, a spherical structure that produces ribosomes
- Has a double membrane with pores through it
Explain the structures of ribosomes and its function (both prok and euk).
- catalyzes the synthesis of polypeptides during translation (common function)
- composed of two subunits that come tgt to form a functioning structure
In eukaryotes, give the two categories of ribosomes
1.) Free = floating in cytoplasm, synthesizing polypeptides (the blue string) used within the cell
2.) Bound = attached to the rough endoplasmic reticulum (green), synthesizing polypeptides that are secreted from the cell or become integral proteins in the cell membrane
Describe the structure and functions of the Rough Endoplasmic Reticulum [4]
- a series of flatten membranous sacs
-“membranous” because it carries proteins alike the cell membrane - Play a central role in the synthesis and transport of polypeptides.
- Like amazon. Creates products and ships it.
- has bound ribosomes which synthesize the polypeptide and release it to the inside of the RER.
- the RER membrane is continuous with the nuclear envelope, which surrounds the cell nucleus
- basically attached to outside of nucleus.
(Think of it like Amazon. And the bound ribosomes are the employees)
Describe the smooth endoplasmic reticulum
- a series of connected flattened membranous sacs that are continuous with the RER.
- In contrast to the RER, smooth endoplasmic reticulum lacks ribosomes and is not involved in protein synthesis
- Main Function*: synthesis of phospholipids and cholesterol (lipids)
Describe the golgi apparatus’ functions
- modify polypeptides into their functional state
- the golgi sorts, concentrates and packs their proteins into vesicles
- like delivery centers — the drop off points of Amazon (RER) ??
- vesicles are like the package
- depending on the contents, the vesicles are dispatched into one of three destinations:
- Within the cell, to lysosomes (synthesized by free ribosomes)
- The plasma membrane of the cell (synthesized by bound ribosomes)
- Secretion to the outside of the cell via exocytosis (synthesized by bound ribosomes)
Describe vesicles
Membrane bound sacs that contain and transport materials within cells.
Explain the two types of vesicles
1.) Transport vesicles - move molecules between locations inside the cell by budding off one organelle compartment.
2.) Secretory vesicles - secrete molecules from the cell via exocytosis.
- They are also *how new phospholipids are added to the cell membrane.
Describe the lysosome
-
small spherical organelles, enclosed by a single membrane.
- aka suicide bags
- contain enzymes that work in oxygen-poor areas and lower pH
-
enzymes digest large molecules (function) to degrade and recycle the components of the cell’s own organelles when they are old or damaged, or if the cell is ‘starving’ in the absence of nutrients (purposes)
- lysosome: the “fix-it”/feeding company; the enzymes: the handy men
-
also has an immune defense function by digesting pathogens that have been engulfed by phagocytes.
- lysosome also doubles as a security company! They contain threats engulfed by phagocytes!
- phagocytes: security guards
- pathogens: intruders (e.g. harmful bacteria)
Describe mitochondria
- mitochondria apadted for production of ATP by aerobic cellular respiration
- mitochondrion is surrounded by a double membrane
- because according to endosymbiosis, the ancestor of the mitochondria (a prokaryote cell) had its own membrane before being swallowed
- mitochondria evolved by endosymbiosis
Describe chloroplasts
- adapted for photosynthesis, converts sunlight to glucose via water and carbon.
- chlorophyll, light absorbing pigments, give the chloroplast its characteristic green color.
- chloroplasts evolved by endosymbiosis.
Describe vacuoles in plant cells
Purpose: water storage
- In mature plant cells, a central vacuole contains 30% - 90% of the volume of the cell.
- In addition to water storage, the main role of the vacuole is to maintain turgor pressure against the cell wall
-
Turgor pressure = mechanism the plants use to remain upright
- forces cell wall to protect the plant cell from the pressure and thus maintain posture by fighting pressure (??)
Describe cytoskeleton
IT IS NOT AN ORGANELLE (even if its present within both prokaryotic and eukaryotic cells)
It is a “backbone” or “skeleton” in the sense that it:
- helps cells maintain their shape
- organizes cell parts
- enables cells to move and divide (because it is made from microtubules)
Outline the components working together to form the cytoskeleton
- Several different components work together to form the
cytoskeleton, including: - microtubules
- actin filaments
- intermediate filaments
Describe/explain what are microtubules
Polymers of a protein called tubulin and form part of the exoskeleton
-Function: intracellular transportation of organelles and separation of chromosomes
- e.g.: in meiosis?
Explain/describe the centrioles
Paired cylindrical-shaped group of organelles composed of nine groups of three microtubules organized with radial symmetry
Functions:
- arrangement of the miotic spindle during cell division.
- anchor points for microtubules in the cytoplasm and for cilia and flagella (which modified to become a basal body)
distinguish and compare Cilia and Flagella
Similarities:
- Extensions from the cell surface which aid in cell movement (think of the sperm tell as an example)
Differences:
- Cilia: protrusions (the “tails”) are short and numerous
- Flagella: longer and less numerous.
Outline the shared processes of life
Homeostasis, Metabolism, Nutrition, Movement, Response to Stimuli, Excretion, Growth, Reproduction
MH GRREMN
Explain and define Homeostasis
Definition: maintaining an equilibrium/balance
- In living organisms, being able to be in homeostasis means to have a stable chemical environment inside despite their external environment
- Can be seen in all organisms
Define and explain metabolism
Definition: sum of all the chemical reactions in a cell.
- Can include polymerization AND the turning of polymers into energy and smaller molecules
- One of the reasons why viruses aren’t “living things”, they can’t metabolize.
Distinguish anabolic and catabolic reaction
Anabolic: energy + smaller molecules (monomers ??) => polymers
Catabolic: larger molecule => energy + smaller molecules (monomers)
Define and explain nutrition
definition: obtaining energy (to do processes) and matter (to get nutrients ??), basically using food to support life
Distinguish the two types of nutrition
- autotrophs - uses external energy (sun) to synthesize inorganic -> carbon compounds
- heterotrophs - gets carbon carbons to synthesize from OTHER organisms.
Define movement
Definition: changing location
Describe the two types of organisms according to mvmt.
1.) Sessile organisms - stay in one place
2.) Motile organisms - mobile
Define excretion
Definition: metabolic waste (e.g. poo) is eliminated from an organism
Describe how excretion is seen in living orgs
(Reminder! Excertion doesn’t always mean poop and pee, can also mean exhaling of carbon dioxide)
- excretion primarily occurs via lungs
- in many plants, excretion occurs via leaves, roots and stem
- excretion occurs through the cell membrane, which is one reason cells must have a large surface area to volume ratio (to excrete the cell waste)
Define growth (and development
Increase in size and mass of an organism
- Sub-topic to growth: development - transformation of the organism (e.g. metamorphosis or seed -> tree, could also be mitosis of amoeba)
Describe the process of “response to stimuli”
To recognize and respond to changes in environmental conditions
Describe the process of reproduction
life will create more life
Describe the two types of reproduction
1.) Sexual reproduction - 2 parents, fusion of haploid cells
- meiosis.
- due to more parents, there’s more genetic variation
2.) Asexual reproduction - 1 parent only.
- genetically identical offspring
- binary fission and mitosis
Could unicellular organisms carry out all the processes of life?
Yis (bc they have cell)
Outline how paramecium displays the basic processes of life
Outline how paramecium displays the basic processes of life (pt 2 SYNTHESIZE)
Outline how chlamydomonas displays the basic processes of life (SYNTHESIZE)
Outline how chlamydomonas displays the basic processes of life (SYNTHESIZE)
Define “Eukaryota”
The domain of Eukaryota is a domain (classification of living things)
- includes: eukaryotic cells
Describe the creatures under domain Animalia
Theyre called “animals”, largest kingdom
- multicellular eukaryotes w/o a cell wall
- holozoic (eat other organisms with internal digestion of nutrients, does this include plants?)
Describe what can be under “Fungus’
- Eukaryotes with a cell wall made of chitin
- uni- OR multi-cellular
-
MOSTLY saprotrophs
- secrete digestive enzymes into their environment and then absorb the nutrients into their body after there has been external digestion
- some are parasitic
- principal decomposers
Describe the kingdom Plantae
“plants” - multicellular eukaryotes with a cellulose cell wall
- autotrophs (make their own food)
- feel almost all heterotrophs
- 300,000 species of plants known
Outline the similarities in Eukaryota Cell Structure
Among animal, fungi and plant cells..
Explain the differences in cell structure in relation to plastids
Plastids - any of a class of small organelles, such as chloroplasts, in the cytoplasm of plant cells, containing pigment or food.
Explain the differences in cell structure in relation to cell walls
Cell wall - external to plasma membrane, provides strength
Explain the differences in cell structure in relation to vacuoles
Explain the differences in cell structure in relation to centrioles
Explain the differences in cell structure in relation to cilia and flagella
Distinguish between trends and discrepancies
1.) trend - typical, prevailing tendency
- give predictions
2.) discrepancy - atypical, does not fit the trend
- lead to scientific questions
Outline three examples of trends
- cells are small
- all living things are composed of true cells
- cells come from pre-existing cells
basically cell theory + that there are typical cell structures
Explain the discrepancy of red blood cells
It is a eukaryotic cell without a nucleus or mitochondria!
- what makes it eukaryotic?: they are produced by a eukaryotic organism and to begin with they do contain a nucleus
- for what purpose?: to carry more oxygen
Describe the discrepancy of the aseptate fungal hyphae
- What is that?: When Fungal hyphae are not made of clearly defined indv. cells, they’re called Aseptate hyphae
- Aseptate hyphae are not made of clearly defined individual cells, rather continuous structures with multiple nuclei
- for something to be a living thing, it must have a cell but how about something with multiple organelles but no clearly defined cell?
Describe the discrepancy of skeletal muscles
A very large cell with more than one nucleus
Define sieve tube elements
specialized plant cells that are part of the phloem, transports organic compounds during photosynthesis
Outline the discrepancy of phloem sieve element
A eukaryotic cell without organelles
Explain why the phloem sieve tube element as no nucleus and organelles?
To have more space for the transport of phloem sap (resembles the rbcs reasons for having no nuc a lil!)
Define micrographs
A photograph taken through a microscope to show the magnified image.
Distinguish the two different types of micrographs for prokaryotic cells
Distinguish the two different types of micrographs for plant cells
Distinguish the two different types of micrographs for animal cells
What part of the cell is this?
Nucleus.
What part of the cell is this?
What part of the cell is this?
Smooth ER
What part of the cell is this?
Golgi apparatus
What part of the cell is this?
Lysosome
What part of the cell is this?
Mitochondria
What part of the cell is this?
free ribosomes - synthesize polypeptides during translation
What part of the cell is this?
chloroplasts
What part of the cell is this?
Vacuole
What part of the cell is this?
Vesicles
What part of the cell is this?
Centrioles
What part of the cell is this?
NOT AN ORGANELLE — Cytoskeleton
What part of the cell is this?
Cilia
What part of the cell is this?
Flagella
What part of the cell is this?
Cell Wall
What part of the cell is this?
Cell membrane
What part of the cell is this?
How to draw and label a drawing of something viewed under the microscope?
HOW TO DRAW ANIMAL CELL
HOW TO DRAW PLANT CELL
Define ultrastructures
cellular structures (something that is structured to be a cell) that are to small to be seen by a light microscope
- Includes only prokaryotic cells (aka bacteria and archaea)
Give and explain the reason why the golgi apparatus and the endoplasmic reticulums (both of them) and the nuclear envelope have that curvedshape
Infolding
- evolved from the inward folds of ancestral prokaryotic cells (maybe relate this with the characteristics of prok. cells).
- Allows for more complex chemical reactions in different compartments (explain pls miss??)
Explain how ”endosymbiosis” explained the origin of mitochondria
Hypothesis: They were once aerobic bacteria and an ancestral host cell ingested some of these aerobic bacteria. Some of these bacteria remained and continued to perform respiration within the host cell.
- why aerobic?: Mitochondria burn oxygen and provide energy for the body, therefore the ancestral cells which were supposedly external to the eukaryotic cell, must be aerobic.
Explain ”endosymbiosis” on the origin of chloroplasts
Hypothesis: The ancestors were photosynthetic bacteria that lived inside a large host cell. Instead of being digested, some remained and continued to perform photosynthesis
- mitochondria evolved first before chloroplasts
Outline the structural evidence that supports the endosymbiosis theory [5]
1.) Structural evidence:
- Mitochondria and chloroplasts have the same size and shape as prokaryotic cells;
- They both have a double membrane — implies that they had their own membrane before being engulfed by the eukaryotes;
- also had 70s ribosomes when eukaryotes had 80s ribosomes.;
- have circular naked DNA like that of prokaryotic cells;
- common genetic sequences* with prokaryotes;
Outline the functional/behavioral evidence of enodymbiosis
both mitochondria and chloroplasts:
- move independently within the eukaryotic cell (seem that they had their own life, an organism)
- reproduce independently of the host cell through a process similar to *binary fission
- inhibited by probiotics like prokaryotes
Define genome(s). Explain how they are seen in the organisms
The genetic information of an organism
- ALL cells within an organism share a genome.
Explain why genomes are called “housekeeping genes”
They are code for proteins that are associated with the basic cellular functions
- includes cell cycle regulation, DNA replication and metabolism
(ahh so it’s like if the proteins are the computers, the genomes are the programs, because of their genes they’re inclined to do their cellular processes)
Outline the reason why, even with the same genomes, there are cells which have dissimilar/specialized shapes and functions?
Differentiation
- development of specialized structures and functions of cells
Explain how differentiation occurs
- Occurs: when different cell types express different genes.
Example:
For genes that are not genomes of a certain thing, what is the implication on their gene expression?
Some cell types express the gene whereas other cell types don’t
Outline how are stem cells able to specialize?
They turn off some genes (aka do not express them) and express others
Outline (the two ways) how environmental conditions can change gene expression.
The expression of genes in an organism can be influenced by the enviornment:
1.) External world
- where the organism is located and develops
- e.g.: drugs, chemicals, temperature, light
- for instabce: protein provides coloration on the skin and hair/fur is called melanin.
2.) Internal world
- includes its hormones and metabolism
Define tissues
Group of cells that have differentiated in the same way to perform the same function
Outline the benefits of cell specialization (ASK QUESTION)
It is more efficient because:
- cells can focus on fewer tasks at once to conserve energy
- they evolve to doing those tasks better
- can have specialized structures and metabolism
- wdym by specialized metabolism
When was the evidence of multicellularity?
2500 million or billion (?) years ago
Define the concept of “multicellularity” and give examples
Organisms composed of more than 1 cell
- all animals
- all plants
- most, but not all, fungi
- what are the exceptions?
- many but not all algae
- exceptions?
Explain the evolution of multicellularity
**Evolved independently many times in eukaryotes **
Steps:
1.) Formation of clusters from single cells
2.) Differentiation of cells within cluster for specialized functions
- (e.g. tissues?)
Outline two hypotheses for how cells may have formed clusters in the evolution of multicellularity
1.) A group of independent cells come together
2.) When a unicellular organism divides, the daughter cells fail to separate, causing in an aggregate of identical cells
Give the characteristics of clusters
- selective advantage over independent cells
- begins to serve specialized functions
Define and explain “biofilms”
a thin, slimy film of bacteria
(biofilm dispersion happens when the cells do not produce the glue needed for holding the biofilm (and thus the bacteria jelly that holds all of the, tgt)
Give the formula to get the FOV diameter in HP
Give the two methods of estimating the size of the specimen in the microscope field of view
Explain exocytosis
Definition: The release of cell contents from the cell to the outside
Process: The vesicles “bud”/“fuse” with the plasma membrane to release the contents of the vesicles.
Explain ATP.
Adenosine triphosphate (ATP) is the source of energy (bc of its high energy) for use and storage at the cellular level.
- mitochondria produces ATP but not energy
- energy currency
Explain turgor pressure
Liquid has a pressure. When a cell stores liquid such as water the pressure of the water will push out the cell.
- Therefore, for the plant cell and the fungi cell, they need a cell wall to reinforce their shape (counter-pressure?)
Explain infolding
Describe the DNA in nucleoid
Naked (uncoiles) and linear
