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FUN E > E1 Introduction to cells > Flashcards

E1 Introduction to cells Flashcards

1
Q

what are some exceptions of cells that can replicate themselves?

A
  • erythrocytes
  • platelets
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2
Q

describe the nuclear structure of prokaryotes

A

no defined nuclear structure

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3
Q

describe the nuclear structure of eukaryotes

A

defined nuclear structure

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4
Q

what is the main principle of viruses?

A

need a host to live / replicate

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5
Q

what is the cytosol?

A
  • represents the water containing inorganic ions and small organic molecules and accounts for 70-80% of the weight of a living cell
  • macromolecules (proteins, polysaccharides, lipids and DNA/RNA) account for the remaining weight of the cell
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6
Q

what is cytoplasm?

A

a semi-solid / fluid that typically includes all contents: cytosol, various organelles of the cell outside the nucleus and within the cytoplasmic membrane

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7
Q

describe how form relates to function in a red blood cell

A
  • discoid shape and lack of nucleus facilitates movement through blood vessels
  • provides large SA for gas exchange and for sticking to each other to form blood clots
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8
Q

describe how form relates to function in an epithelial cell

A
  • any cells in contact with the outside environment
  • some have microvilli at one end giving the cell polarity and a larger surface area for the absorption of nutrients
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9
Q

describe the function of a chondrocytes

A
  • found in cartilage and embedded in a thick extracellular matrix of proteins
  • hold water for cushioning / shock absorption eg. in knees
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10
Q

describe the nucleus structure and function

A
  • contains DNA in chromosomes
  • diploid (except gametes)
  • surrounded by double membrane (outer and inner nuclear membrane)
  • some cells have more than one
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11
Q

describe the nuclear membrane

A
  • nuclear envelope is a lipid bilayer and is continuous with the ER
  • hydrophobic and hydrophilic domains
  • large structures can’t move through
  • need transporters or pores
  • nucleus has pores that allow newly formed ribosomes to move through
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12
Q

what is the nuclear lamina?

A

a dense network of protein fibres that help provide structural integrity

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13
Q

give an example of cells that have more than one nucleus

A

osteoclasts

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14
Q

describe the structure of the endoplasmic reticulum

A
  • membrane bound
  • network of cistern with a common, interconnected lumen
  • in contact with the nuclear membrane
  • receives ribosomes form the nuclear pores
  • rough has ribosomes attached for translation
  • smooth has no ribosomes attached
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15
Q

how is the destination of ribosomes decided?

A

based on what proteins they end up coding for and where these proteins go to

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16
Q

describe the function of the ER

A
  • rough ER has ribosomes for translation
  • proteins are synthesised (translated) then modified within the ER before being passed to the Golgi or lysosomes for further modification
  • stores calcium ions (especially in sarcomeres)
  • synthesises lipids and steroids
  • detoxifies drugs in liver cells
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17
Q

describe the structure and function of the Golgi

A
  • similar to ER (derived from ER but no longer connected)
  • stacks of flattened smooth membrane sacs and vesicles
  • ribosomes from nucleus to ER then ER makes proteins which are delivered to Golgi
  • undertakes post-translational modification of many proteins
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18
Q

describe the structure of Golgi membrane sacs

A
  • cis (facing ER) receives proteins and lipids from ER
  • stack (main body) processes proteins and lipids
  • trans (facing cytoplasmic membrane) targets delivery of proteins etc.
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19
Q

describe the structure of the mitochondria

A
  • double membrane structure
  • enzymes of ETC embedded in the inner membrane
  • enzymes involved in Krebs cycle and fatty acid oxidation in matrix
  • has own DNA, RNA and ribosomes
  • inherited maternally from egg cell, sperm only has nucleus in its head
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20
Q

describe the mitochondrial genome

A
  • very small
  • encodes for some RNAs and some ETC proteins
21
Q

why does the number of mitochondria vary between cells?

A
  • muscle cells have more for contraction
  • other cells have less due to their functional adpatations
22
Q

why are inherited diseases usually inherited from the mother?

A
  • mitochondrial diseases
  • mitochondria are only inherited from the mother
23
Q

describe the structure and function of lysosomes

A
  • pinch off Golgi so are derived from Golgi complex
  • contained environment
  • different pH to cell and allows for different chemistry
  • contain various enzymes that work in acidic environment
24
Q

describe the structure and function of phagosomes

A
  • found in specialised cells eg. macrophages
  • break down ‘foreign bodies’ eg. bacteria
  • perform phagocytosis
  • antigen-presenting cell afterwards for the immune system
25
Q

what are peroxisomes?

A

organelles involved in redox reactions

26
Q

what are endosomes?

A
  • structures formed by pinching off part of the cytoplasmic membrane
  • happens when material like lipoproteins or ‘foreign bodies’ are brought into the cell
27
Q

are ribosomes classified as an organelle? explain

A

no, they are not membrane-bound

28
Q

describe the structure and function of ribosomes

A
  • site of protein synthesis
  • 2 subunits
  • decodes mRNA in translation and creates protein from genetic code
  • complex of rRNA and ribosomal proteins
29
Q

describe the structure of different types of ribosomes in detail

A
  • there are large and small
  • eukaryotic are 80S
  • prokaryotic are 70S
  • complexes of rRNA and ribosomal proteins
  • rRNAs fold and interact to give the ribosome 3D structure
30
Q

describe the structure of the cytoskeleton

A
  • made of distinct filamentous proteins that provide an internal scaffold
  • consist of microfilaments, intermediate filaments and microtubules
31
Q

describe the structure and function of the microfilaments in a cell’s cytoskeleton

A
  • eg. actin
  • provide mechanical support
  • actin binds many different proteins and contributes to many cell functions
32
Q

describe the structure and function of the intermediate filaments in a cell’s cytoskeleton

A
  • bigger than microfilaments
  • eg. keratin, desmin
  • mechanical strength
  • resistance to shear stresses
  • air through lungs detected by changes in cytoskeleton
33
Q

describe the structure and function of the microtubules in a cell’s cytoskeleton

A
  • bigger than microfilaments and intermediate filaments
  • eg. tubular involved in movement / separation of chromosomes (‘mitotic spindle’)
  • centrioles found in animal cells (and some plants)
  • paired structures associated with mitosis - centrosome
  • single structures associated with cilia or flagella
34
Q

describe the structure and function of muscle cells in relation to the cytoskeleton

A
  • contain specific protein fibres (actin and myosin)
  • in skeletal and cardiac tissues, the contractile fibres are arranged into prominent structures called sarcomeres
  • smooth muscles have less defined sarcomeres and they contract in a twisting manner
35
Q

describe the structure and function of the cytoplasmic membrane

A
  • all cells bound by a membrane
  • interacts with environment and regulates movement across it with designated transporters
  • phospholipid bilayer
  • organelles’ membranes have similar properties for their membranes
36
Q

describe the structure of a phospholipid bilayer

A
  • 2 phospholipid layers / leaflets
  • assemble to form closed bilayer due to amphipathic properties (hydrophobic and hydrophilic)
37
Q

what do the interactions of the cytoplasmic membrane depend on?

A

interactions depend on properties of the membrane and the molecules embedded in or on the membrane

38
Q

describe the structure of prokaryotes (bacteria mainly)

A
  • DNA is free-floating in the cytoplasm
  • smaller genome
  • less complex
  • haploid
  • reproduce quickly
  • transcription and translation are similar processes
  • naked, extra-chromosomal DNA
  • ribosomes are smaller
  • good target for drugs due to subtle differences in structure and biochemistry
  • rigid cell wall made of distinctive molecules
  • lack membrane-bound organelles
39
Q

describe the DNA in bacteria

A
  • plasmids
  • linked to pathogenicity
  • resistant to antimicrobials
  • insert genes into plasmids for DNA technology
40
Q

what features of bacteria make them a good target for drugs?

A
  • cell wall, animal cells don’t have one
  • different structure and biochemistry
41
Q

where can spore-forming prokaryotes be a problem and why?

A
  • in hospitals
  • they can survive many years and are resistant to many antimicrobials
  • can be a major cause for infections
42
Q

what are some recognisable conditions caused by viruses?

A
  • measles
  • hepatitis
  • covid
  • influenza
  • HPV
  • HIV
  • colds
43
Q

describe the genomes of viruses compared to eukaryotic cells

A
  • simple but no less complex
  • variation among viruses
44
Q

describe how viruses can be classified

A
  • naked or enveloped
  • by the host or the tissue they infect eg. hepatitis is liver
45
Q

describe the anatomy of a virus particle

A
  • capsid protects genome
  • assembly of viral proteins protect genomic material
  • capsid encapsulates a small number of enzymes / other proteins
  • capsomers bind receptors on host cells to help facilitate invasion of them
46
Q

what is tissue tropism in viruses?

A
  • viruses recognise receptors on our cells which is why certain viruses affect certain organs / tissues and cause certain diseases
  • this is why certain viruses cause specific symptoms / diseases
47
Q

describe naked classified viruses

A
  • capsid only
  • eg. papilloma virus, Polio, Hepatitis A
48
Q

describe enveloped classified viruses

A
  • capsid surrounded by lipid bilayer or ‘envelope’ (lipid is derived from the host cell which it pinched off from)
  • envelope also contains viral proteins for targeting / infecting specific cell types
  • eg. HIV, influenza A, influenza B, Coronaviruses

FUN E (11 decks)

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