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Flashcards in W3 - The Cell Deck (49)
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1
Q

Discovery of the cell

A

Robert Hooke, 1665

Looked at a thin slice of cork through his 2-lens microscope.

= Discovered tiny, hollow structures + called them cells.

2
Q

Who proposed the ‘cell theory’ and when?

A

Theodor Schwann

1839

3
Q

What does the ‘cell theory’ state?

A

All organisms are made up of 1 or + cells

Cell is the basic unit of life, the smaller unit that shows all characteristics of life

All cells come from pre-existing cells.

4
Q

Do prokaryotes have a distinct nucleus bounded by a membrane?

A

NO

5
Q

Do prokaryotes have membrane bound organelles?

A

NO

6
Q

What are plasmids?

A

Small circular extrachromosomal DNA mol

7
Q

How many cells does the human body contain?

A

Around 37.2 trillion

8
Q

Cytoplasm

A

Jelly like material in which organelles ‘float’

9
Q

Cytosol

A

Soluble part left of the cytoplasm if all the organelles were removed.

10
Q

What is the central dogma of molecular biology?

A

Flow of genetic info w/in a biological system.

11
Q

What are the 3 processes of central dogma of molecular biology?

A

Replication

Transcription

Translation

12
Q

Around how many genes do humans have?

A

25,000

13
Q

Give examples of structural proteins

A

Collagen

Elastin

Keratin

14
Q

Give examples of motility proteins

A

Actin

myosin

Tubulin

15
Q

Give examples of storage proteins

A

Ovalbumin

Casein

16
Q

Give examples of hormonal proteins

A

Insulin

Nerve growth factor (NGF)

17
Q

What % of cellular ATP is made in the mitochondria by oxidative phosphorylation?

A

Just over 80%

18
Q

Endosymbiotic theory

A

Mit were primitive bacterial cells.

Millions of years later… mit + eukaryotes became mutually beneficial.

NOW a permanent dependent relationship.

19
Q

Mitochondria DNA

A

Circular

Comes only from the mother

20
Q

How many genes roughly does mit DNA encode for?

A

37

21
Q

Where are SER more prominent in?

A

Adrenal cortex (secreting steroid hormones)

Hepatocytes

Sarcoplasmic reticulum of muscle cells

22
Q

Describe the Golgi apparatus

A

Stacks of membrane bound cistern between the ER + surface of cell.

23
Q

Function of Golgi apparatus

A

Processing of proteins synthesised in the RER

24
Q

What are ribosomes made of?

A

Protein

rRNA

25
Q

What does the ribosome do to make new protein?

A

Clamps over tRNAs + mRNAs

26
Q

What are the 3 main sites on a ribosome?

A

A

P

E

27
Q

A site on a ribosome

A

Receives new tRNA

28
Q

P site on ribosome

A

Receives peptide-bearing tRNA after peptide bond formation

29
Q

E site on ribosome

A

Where tRNAs exit

30
Q

What are the 4 major proteolytic systems?

A

Lysomomes - The ‘bulk’ protein breakdown

ATP dependent ubiquitin proteasome - protein breakdown

Calpains

Caspases

31
Q

How are lysosomes created?

A

When early endoscopes from Golgi apparatus have hydrolytic enzymes added to them.

32
Q

At what pH do lysosomes work best at?

A

Around 5

33
Q

What are calpains?

A

Calcium activated degredated proteins.

34
Q

What do calpains do?

A

Cleave + breakdown proteins in elevated levels of Ca2+

35
Q

What are peroxisomes?

A

Membrane bound enzyme sacs

36
Q

What do peroxisomes do?

A

Carry out oxidation reactions to prod H202. (Hydrogen peroxide)

+ oxidative reactions for uric acid, aa + FAs

37
Q

What is the cytoskeleton?

A

Network of protein fibres

38
Q

What are the functions of the cytoskeleton?

A

Mechanical strength

Locomotion

Remodelling

Chromosome separation in cell division

Intracellular transport of organelles

Cellular signalling

39
Q

What are microfilaments in the cytoskeleton?

A

Linear polymers of actin subunits.

40
Q

Characteristics of microfilaments in the cytoskeleton

A

Flexible

Strong

Resist buckling (compressive forces)

Resist filament fracture (tensile forces)

41
Q

What are microtubules in the cytoskeleton?

A

Linear polymers of tubulin that act as conveyer belts in cells.

42
Q

What do microtubules in the cytoskeleton do ?

A

Move vesicles, granules, organelles + chromosomes via special attachment proteins.

43
Q

What do intermediate filaments in the cytoskeleton do?

A

W/stand mechanical stress.

44
Q

What are focal adhesions?

A

Multi-protein structures forming mechanical links between intracellular actin bundles + extracellular substrate.

Large

Dynamic

Connects cytoskeleton of cell to ECM.

45
Q

How many protein components do focal adhesions comprise of?

A

At least 150

46
Q

What are signalling molecules (a.k.a ligands) ?

A

Mol that bind specifically to other mol i.e receptors.

Message carried by the ligands is relayed through a chain of chemical messengers in the cell.

47
Q

Briefly lay out the signal transduction pathway

A

Ligand / extracellular signal mol

Receptor

Chemical messengers in cell to relay signal

Response

48
Q

What is the result of a ligand binding to a cell-surface receptor?

A

Receptor’s intracellular domain changes shape.

= Sets off signalling events.

49
Q

Is signalling nonlinear?

A

YES