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The Cell > week 1 > Flashcards

week 1 Flashcards

RER - Rough endoplasmic reticulum SER - Smooth endoplasmic reticulum GA - Golgi Apparatus E - eukaryotic P - prokaryotic

1
Q

what are the properties of the main molecules of life?

A
  • Amino Acids polymerise into Proteins
  • Purines and Pyrimidines polymerise into Polynucleotides
  • Polynucleotides can directly guide the formation of exact copies of their own sequence (base pairing of DNA)
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2
Q

what did early earth consist of?

A
  • Molten Surface?
  • Atmosphere ammonia or methane?
  • Little free Oxygen
  • No Ozone
  • Generally agreed –violent conditions, volcanic eruptions, lightning, storms….
  • Great conditions for producing simple carbon-based (organic) molecules
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3
Q

what happens if you mix gases sucg as CO2, CH3, NH3 and Hydrogen in water?

A

they react to form small organic molecules Purines, Pyrimidines,Sugars, Amino Acids

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4
Q

what is the function of a plasma membrane?

A
  • Every cell is surrounded by a plasma membrane
  • Maintain homeostasis
  • Selectively permeable
  • Important in communicating without side environment
  • Aids in binding and adhering
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5
Q

what does cell theory state?

A

– Cells are the fundamental units of life.

– All organisms are composed of cells.

– All cells come from pre-existing cells.

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6
Q

who was Robert Hooke and what did he discover?

A

The cell was first described by Robert Hooke

He remarked that they looked strangely similar to cellula or small rooms whichmonks inhabited, thus deriving the name.

However what Hooke actually saw were the dead cell walls of plant cells (cork) as they appeared under the microscope

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7
Q

who was Anton Van Leeuwenhoek and what did he discover?

A

The first man to witness a live cell under a microscope was Anton Van Leeuwenhoek, who in 1674 described the algae Spirogyra.

Leeuwenhoek probably also saw bacteria when looking at the algae but didn’t describe them at the time

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8
Q

how is a plasma membrane structured?

A

The plasma membrane is a lipid bilayer with proteins and other molecules embedded in it. Some archaea have a lipid monolayer.

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9
Q

what is the size of the smallest object a person can see?

A
  • Smallest object a person can see is about 0.2 mm (200 μm) in size

.* Objects must be about this distance apart for them to be distinguished from one another (resolution).

  • Most cells smaller than 200 μm in size
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10
Q

what is the resolution of a Light Microscope?

A

Resolution 0.2 μm (About 1000 times that of the human eye

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11
Q

what is the famous quote from Matthias Jakob Schleiden? (Cell Theory)

A

“All plants are made up of cells”

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12
Q

what is the famous quote from Rudolf Virchow? (Cell Theory)

A

“Cells come from cells”

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13
Q

what is the famous quote from Theodor Schwann? (Cell Theory)

A

“The cause of nutrition and growth resides not in the organism as a whole but in the elementary parts – the cells.”

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14
Q

who came first out of Scheiden, Virchow and Schwann?

A

the order is as follows:

Schleiden - “all plants are made up of cells”
Virchow - “Cells come from Cells”
Schwann - “The cause of nutrition and growth resides not in the organism as a whole but in the elementary parts – the cells.”

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15
Q

what is the resolution of a electron microscope?

A

The resolution 0.2 nm.

(About 1,000,000 times greaterthan the human eye)

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16
Q

what is cell size limited by and how?

A

Cell size is limited by the surface area-to-volume ratio.

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17
Q

what is meant by surface in relation to cell size?

A

The surface of a cell is the area that interfaces with the cell’s environment.

18
Q

what is meant by cell volume?

A

The volume of a cell is a measure of the space inside a cell.

19
Q

what is meant by surface-area: volume ratio?

A
  • Surface - area: volume ratio is defined as the surface area divided by the volume.
  • For any given shape, increasing volume decreases the surface -area: volume ratio
20
Q

why do we use the surface-area: volume ratio？

A
  • The volume of a cell determines how much chemical activity it can carry out per unit of time.
  • The surface area of the cell determines the amount of a substance it can take in from the external environment and how much waste itcan release into the environment.
21
Q

what is unique about the structure of Prokaryotic cells when compared to Eukaryotic cells?

A

they have no nucleus or other membrane-bound compartments. They lack distinct organelles

22
Q

what is unique about the structure of Eukaryotic Cells in comparison to Prokaryotic cells?

A

Eukaryotic Cells have a membrane-enclosed nucleus and other membrane-enclosed compartments and organelles

23
Q

what are the shared features of prokaryotic and eukaryotic cells?

A

Cytoplasm
Ribosomes
Nucleoid
Plasma
Membrane

24
Q

Do prokaryotic cells have cell walls?

A
  • Some prokaryotic cells have Cell Walls
  • Located outside plasma membrane
  • Maintains shape of cell
  • Cell wall of most bacteria (Not Archaea) contains peptidoglycan (sugars and amino acids)

*In some bacteria (Gram –ve) an outer layer of lipopolysaccharide (lipid and pilysaccharide) and protein encloses the peptidoglycan layer

25
Q

what is a mycoplasma?

A
  • Bacteria that lack a cell wall
  • This makes them unaffected by some antibiotics such as penicillin
26
Q

what is the capsule in prokaryotic cells?

A
  • Some bacteria also have a layer of slime enclosing the cell wall.
  • This is mostly polysaccharides and is referred to as the capsule

Capsule can protect bacteria from attack by white blood cells in animals they infect. Also stops the bacterium drying out and can help it attach to other cells. The capsule is not necessary for the survival of the bacterium and if it is lost the bacterium cansurvive

27
Q

can prokaryotic cells undergo photosynthesis? if they can how do they do this?

A

Cyanobacteria and some other bacteria have a complex and highly organised system of internal membranes with which to carry out photosynthesis

28
Q

what are the corkscrew structures found in some prokaryotic cells known as?

A

Some prokaryotic cells have flagella, locomotory structures shaped like corkscrews

29
Q

what are the helical structures found in some prokaryotic cells used for?

A

Some prokaryotes have a helical structure just inside the plasma membrane which is made up of proteins very similar to actin in eukaryotes.

It has been suggested that this protein is responsible for maintaining the structure of the cell

This structural protein is not found in spherical bacteria.

However, this is not a
‘true’ cytoskeleton and as such prokaryotes do not undergo mitosis. They divide by a process known as binary fission after replicating their DNA.

30
Q

what are the function of endospores in prokaryotic cells?

A
  • Some bacteria produce dormant,resistant endospores within vegetative cells.
  • Endospores are highly resistant to environmental stresses such as high or low temperature or drought.
31
Q

what are the main characteristics of eukaryotic cells?

A
  • Generally have dimensions upto 10 times greater than prokaryotic cells

.- Like prokaryotes they have a plasma membrane, cytoplasm and ribosomes.

  • Contain a membrane-bound nucleus

.- Also have membrane

-boundorganelles and a protein scaffolding called the cytoskeleton.

  • Compartmentalization is the key to eukaryotic cell function.
  • Each organelle or compartment has a specific role defined by chemical processes.
  • Membranes surrounding these organelles keepaway inappropriate molecules and also act as traffic regulators for raw materials into and out of the organelle.
32
Q

what is the function of the nucleus in eukaryotic cells?

A
  • Usually the largest organelle in the cell.
  • Contains most of the cell’s genetic material(DNA).
  • Replication of DNA and the first steps in decoding it for protein production take place in the nucleus.
33
Q

what is the function of the RER (rough endoplasmic reticulum) in eukaryotes?

A
  • ER can enclose up to 10% ofthe interior volume of the cell.
  • Rough ER (RER) is studded with ribosomes which are temporarily attached to itsouter surface.
  • RER segregates newly synthesised proteins away from the cytoplasm and transports them to other areas of the cell.
  • While inside the RER proteins can be chemically modified to alter their function and destination
34
Q

what is the function of the SER (smooth endoplasmic reticulum) and how is it different from the RER?

A
  • More tubular than RER.
  • Lacks ribosomes on the outside.
  • Responsible for chemical modification of small molecules taken into the cell –drugs.
  • Site of hydrolysis of glycogen(multi-branched polysaccharide of glucose) in animal cells.
  • Site for synthesis of lipids and steroids
35
Q

what do ribosomes do in eukaryotic cells?

A
  • In prokaryotic cells Ribosomes float freely in the cytoplasm.
  • In Eukaryotic cells they are found in 2 places
    – 1. The cytoplasm where they may be free or attached to the surface of the endoplasmic reticulum.
    – 2. Inside mitochondria and chloroplasts.
  • Site of protein synthesis
36
Q

what is the function of the golgi apparatus?

A
  • Usually consists of flattened membranous sacs called cisternae.
  • Receives proteins from RER and may further modify them.
  • Concentrates, packages and sorts proteins before they are sent to final destination.
  • Site of synthesis of polysaccharides for plant cell walls.
37
Q

what are lysosomes in E cells??

A
  • Lysosomes are vesicles containing digestive enzymes that come in part from the Golgi.
  • Lysosomes are sites for breakdown of food and foreign material brought into the cell by phagocytosis.
  • Lysosomes are also the site where digestion of spent cellular components occurs, a process called autophagy
38
Q

what is the function of Mitochondria in E cells?

A
  • These are the ‘power houses’ of the cell.
  • Have their own independent genome which is very similar to bacterial genomes.
  • Energy stored in the bonds of carbohydrates and fatty acids (food) isconverted into a more useful form for the cell (ATP) by ATP synthase in the inner membrane.
  • The number of mitochondria in a cell varies by organism and tissue type.
  • 650 Mitochondrial proteins identified inhuman heart cells – 940 in rats
39
Q

what are plastids?

A
  • Plastids are organelles found only in plants and some protists.
  • Chloroplasts, the sites where photosynthesis occurs, are one type of plastid
40
Q

what are vacuoles?

A
  • Vacuoles have several functions.
  • Storage
  • Structure
  • Reproduction
  • Digestion

The Cell (10 decks)

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