Life at cellular level Flashcards

1
Q

Describe the structures present in all cell types

A
  • Cytoplasm
  • Ribosome
  • Cell (plasma) membrane
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2
Q

Define role of nucleus.

A
  • Contains DNA
  • In a nuclear membrane
  • Nucleoli are sites of ribosomal RNA synthesis and ribosomal assembly
  • Closely associated with RER
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3
Q

Define role of endoplasmic reticulum and Golgi apparatus

A
  • Has RER, SER
  • RER has ribosomes,
  • Ribosomes synthesise proteins
  • RER modifies proteins
  • SER produces lipids, steroid hormones and metabolises toxins
  • Golgi apparatus packages proteins in preparation for transport outside cell
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4
Q

Define role of mitochondria

A
  • matrix contains majority of enzymes required for metabolising food molecules
  • inner membrane has cristae (folds) for larger surface area.
  • outer membrane contains pores
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5
Q

Define role of lysosomes and peroxisomes

A
  • vesicles that contain enzymes
  • Lysosomal enzymes are degradative and digest biological materials
  • Peroxisomal enzymes degrade long chain fatty acids and other foreign toxic materials
  • reactions generate hydrogen peroxide and peroxisomes break down hydrogen peroxide
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6
Q

Define role of cytoskeleton

A
  • maintain cell shape
  • maintains internal cell order
  • Helps with intracellular transport
  • Drives and guides cellular migration
  • Protein fibres of cytoskeleton connect with extracellular space and helps with assembly of tissues
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7
Q

Define role of flagellum and cilium

A
  • projections supported by cytoskeleton
  • Cilia are short, many present, move with stiff power stroke and flexible recovery strokes
  • Flagella are longer, with one or two present and have snakelike movement
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8
Q

Describe structure and function of the eukaryotic cell membrane

A
  • double layer of lipids with phosphate groups attached
  • selectively permeable bilayer
  • embedded with proteins such as receptors to detect signalling molecules
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9
Q

Define stem cells

A

Stem cells can differentiate into many (multipotent) or any (pluripotent) cell types

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10
Q

Describe cell differentiation

A

Differences in gene expression and local cellular environment can cause daughter cells to develop into different cell types

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11
Q

What is apoptosis.

A

Controlled and programmed cell death

normal process and essential for normal function

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12
Q

What is necrosis

A

death of cells in response to injury or infection

not a normal process

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13
Q

What are the major elements used to construct human biomolecules.

A

Hydrogen, Oxygen, Nitrogen, Carbon

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14
Q

State the importance of chemical functional groups

A

Groups of elements that attach to carbon structures and give specific chemical properties to molecule

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15
Q

State the importance of molecular configuration in determining bimolecular function

A
  • fixed arrangement of atoms in a molecule
  • biomolecules contain carbon double bond and have rigid structure
  • only 2 distinct configurations, cis and trans
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16
Q

What is the importance of conformation in bimolecular function.

A

spatial arrangement of groups

groups can have different positions in space due to rotation of single bonds.

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17
Q

What are the 5 chemical reactions occurring in living organisms, with examples.

A
  1. Redox reactions
  2. Making/breaking bonds
  3. Internal rearrangement
  4. Groups transfer
  5. Condensation and Hydrolysis
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18
Q

Describe the general structure of proteins

A

long chains of amino acids formed by condensation reactions

carboxyl and amino group joined by peptide bond

19
Q

Describe the general structure of nucleic acid

A
  • polymers of nucleotide monomers
  • linked by 3,5-phosphodiesterase bonds
20
Q

What are Pyrimidines

A

Cytosine - C

Thymine (DNA) - T

Uracil (RNA) - U

21
Q

What are Purines

A

Adenine - A

Guanine - G

22
Q

Describe the general structure of lipids

A

repeating units of fatty acids

23
Q

What are the different types of fatty acids

A
  • Saturated - single bonds
  • Mono-unsaturated - one double bond
  • Poly-unsaturated - more than one double bond
24
Q

What is the function of fatty acids in the cell membrane

A

fatty acid tail of phospholipids is hydrophobic and allows them to be used for drug delivery

25
Q

Define the term hydrophilic

A

Water loving

molecules that dissolve in water and are polar

26
Q

Give examples of hydrophilic substances

A
  • Sugars
  • Alcohols
  • Aldehydes
  • Ketones
  • Compounds with N-H groups
  • Charged particles such as ions
27
Q

Define the term hydrophobic

A

molecules that do not dissolve in water, minimising contact with surrounding water molecules

28
Q

Give examples of hydrophobic substances

A
  • Fat soluble vitamins (A, D, E, K)
  • Lipids
  • Steroid hormones
  • Oxygen
29
Q

Define the term amphipathic

A

contain both hydrophilic and hydrophobic parts

30
Q

How are proteins amphipathic

A

regions on inside of chain are hydrophobic

on outside are hydrophilic

allows them to be soluble in water

31
Q

Give examples of amphipathic substances

A
  • Sterols (Cholesterol)
  • Phospholipids
32
Q

What is the difference between liposome and micelles

A
  1. Liposomes are a sphere of phospholipids, formed by lipid bilayer and have a hollow core
  2. Micelles are a sphere of phospholipids, formed by single layer of phospholipids
33
Q

What is a chylomicron

A

used to transport lipids in blood

sphere with a shell comprising of proteins and phosphates with lipids stored in core

allows them to be transported in aqueous plasma of blood

34
Q

Define pH

A

measure of concentration of H+ ions in any aqueous solution

35
Q

What is the difference between an acidic and basic solution

A

acidic solution has a higher concentration of H+ ions

basic solution has a lower concentration of H+ ions

36
Q

What is a buffer

A

solution that can resist changes in pH

Weak acids and their bases are used as buffer systems within cells and organisms.

37
Q

What is the phosphate buffer

A

In cytoplasm of cell the phosphate buffer system is important.

Resists pH from 5.9 to 7.9

38
Q

What is the bicarbonate buffer

A

In plasma, bicarbonate system is important

affected by lungs and kidneys through change in CO2 levels or changes in reabsorption or secretion of plasma bicarbonate

39
Q

Define Metabolism

A

continuous flow of energy and matter that involves intermediate metabolites and through pathways of enzyme catalysed reactions

40
Q

Define catabolism

A

breakdown of large molecules and release of energy useful in anabolism

Catabolism and Anabolism are thermodynamically coupled

41
Q

Define anabolism

A

build up large molecules with the use of energy from catabolic reactions

Catabolism and Anabolism are thermodynamically coupled

42
Q

Describe the contribution to metabolic flow of ATP and ADP

A

ATP to ADP releases energy used in anabolism and ADP to ATP uses energy sourced from catabolism

43
Q

Describe the contribution to metabolic flow of NADP+, NAD+ and FAD+

A

involved in redox reactions within cell

This flow of electrons from catabolic reactions to other biological reactions is what ultimately produces energy