Microscopy and Cell structure Flashcards

1
Q

Define the limit of resolution

A

The minimum distance two objects can be distinguished at

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2
Q

What is limit of resolution proportional to?

A

Wavelength

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3
Q

What is the theoretical limit of resolution for a light microscope?

A

0.2 micrometres

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4
Q

What is the theoretical limit of resolution for an electron microscope?

A

0.002nm

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5
Q

What feature of the phospholipid bi layer structure makes it selective, and in what way?

A

Phospholipid molecules are ampipathic - Hydrophillic phosphate groups on outside, hydrophobic lipids on inside. This means they are relatively impermeable to most water soluble molecules.

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6
Q

What feature of phospholipid bilayer allows it to mediate the majority of its functions?

A

Protein molecules dissolved within the membrane

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7
Q

What is the structure of the golgi?

A

Saucer shaped stacks of cisternae

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8
Q

How do vesicles get to golgi, and where do they fuse?

A

Bud off from Rough Endoplasmic reticulum and fuse with the convex cis face of the golgi body

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9
Q

What feature of golgi bodies allows proteins to move through it?

A

Its polarity

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10
Q

In which direction do protein migrate through golgi?

A

From convex cis phase to the the concave trans face of the stack

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11
Q

What are the four function of the golgi?

A

Modify, sort, concentrate and package proteins synthesised on rough endoplasmic reticulum

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12
Q

What two destinations do vesicles budding from the golgi have?

A

Either lysosome assembly or secretion

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13
Q

What is the glycocalyx, and what is their function?

A

The cell “coat made up of oligosaccharide and polysaccharide side chains on the outiside of the plasma membrane Give the cell specificity

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14
Q

What are the 7 functions of the plasma membrane of a cell?

A

Selective permeability Transport of materials along the cell surface Endocytosis Intracellular recognitio Exocytosis Signal transduction Intercellular adhesion

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15
Q

What are the major functions of the nucleus?

A

1) Stores the cells DNA 2) It coordinates the cell’s activities, metaolism, growth, protein synthesis an mitosis

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16
Q

What does most of the nuclear material consist of, and what does it form during mitosis?

A

Chromatin, the unstructured for of the cell’s DNA. Organises to form chromosomes during mitosis.

17
Q

What is the function of nuclear pores withing the nuclear envelope?

A

They allows specific types and sizes of molecules to pass back and forth between the nucleus and cytoplasm.

18
Q

What is the nuclear membrane attached to?

A

A series of tubules called the endoplasmic reticulum

19
Q

What is hte function of the nucleolus?

A

An organelle that synthesises protein producing macromolecular structure called ribosomes.

20
Q

What is the function of ribosomes?

A

Site of translation and also the unit used for protein synthesis.

21
Q

When does a ribosome bind to RER?

A

When it begins to synthesis a protein destined for the secretory pathway

22
Q

Give two major functions of the RER

A

Lsosomal enzymes with a mannose-6-phosphate marker added in the cis-golgi network Secreted proteins, either secreted constitutively or regulated Initial glycosylation - N linked

23
Q

What cells are smooth ER found in and what are their functions?

A

iver and mammary gland, and in the ovaries testes and adrenal glands Assist in lipid and steroid synthesis

24
Q

What do lysosomes contain, and how do they protect themselves against their contents?

A

They contain acid hydrolysases at pH 5. Lysosomal membrane proteins are highly glycosylated for protection from these enzymes.

25
Q

What do primary lysosomes fuse with?

A

Membrane bound vesicles, autophagosomes (defunct organelles) or with excess secretory product to form secondary lysosomes in which contents are degraded.

26
Q

What do peroxisomes do?

A

Major site of oxygen utilisation and H202 production

27
Q

What utilises H202 produced from peroxisomes, and to what effect?

A

Enzyme catalase utilises H202 to oxidise other substancs such as alcohol (half alcohol we drink oxidsed to acetaldehyde)

28
Q

What is interesting about peroxisome reproduction?

A

Self replicating, but no genome of their own

29
Q

Why are peroxisomes most present?

A

In kidney tubules and liver parenchymal cells, where they detoxify toxic molecules in blood stream

30
Q

What is the structure of a mitochondrion?

A

Double membrane with innermembrane thrown into distincy folds called cistae which are usually lamellar

31
Q

What is the primary function of mitochondria?

A

Generation of energy rich ATP molecules by oxidative phosphorylatoion

32
Q

What are the main substrates of mitochondria?

A

Glucose and fatty acids

33
Q

What does the matrix of mitochondria contain?

A

Enzymes involved in krebs and fatty acid cycles, DNA, RNA, ribosomes and calcium granules

34
Q

How can mitochondria divide?

A

Have their own genetic material

35
Q

Where do humans inherit mitochondria from?

A

Maternal line

36
Q

Give four functions of a cell cytoskeleton

A

Structural support or the plasma membrane and cell organelles Means of movement for organelles, plasma membrane and other cytosol constituents Locomotor mechanisms for amoeboid movements (e.g lymphocytes) and for cilia and flagella Contractability in cells of spcialised tissues (muscles)

37
Q

Give four features of microfilaments

A

5nm diameter Two strings of actin twisted together Associated with ATP (contractile) Cann assemble and dissociate (dynamic)

38
Q

Give four features of intermediate filaments

A

Not dynamic 10-12 nm diamete Common in nerve and neurological cells Also common in epithelial cells that are made of cytokeratin. Form tough suporting meshworks in cytoplasm.

39
Q

Give four features of microtubules

A

Thirteen alpha and beta subunits polymerise to form wall of the hollow microtubules They originate from the centrosome Found at sites where structures in cells are moved (mitotic spindle, for instance) Attachment proteins can attach to organelles and move them along the microtubule (movement of chromosomes along mitotic spindles - classic example)