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DSA > Topic 2- Tissue types and movements of molecules across Plasma membrance > Flashcards

Topic 2- Tissue types and movements of molecules across Plasma membrance Flashcards

1
Q

What is a cell

A

Cell: basic structural and functional unit of living organisms, smallest unit of life which can replicate independently(200 different types of cells)

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2
Q

What is Differentiation

A

process whereby cells assume their specialised structure and function

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3
Q

cytoplasm

A

Water substance contains electrolytes, organic molecules and organelles

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4
Q

Mitochondria

A

Powerhouse which produces ATP

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5
Q

Rough Endoplasmic Reticulum

A

site of protein production(ribosomes)

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6
Q

Smooth endoplasmic reticulum

A

Synthesis of lipids

Cell detoxification

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7
Q

Golgi Apparatus

A

Modify, concentrate and package proteins and lipids from the ER

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8
Q

Lysosomes

A

Breakdown foreign or damaged material

Membrane surrounds organelle to separate the ‘nasty’ enzymes from the cell

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9
Q

Cytoskeleton

A

Transport of intracellular organelles

Cell motility, division and contractility

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10
Q

Plasma Membrane

A

Semipermeable membrane which defines cell boundaries

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11
Q

Nucleus

A

Central control of all function i.e. DNA, growth, metabolism and reproduction

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12
Q

Plasma Membrane characteristics

A

Defines the cells boundary

Separates the intracellular and extracellular spaces (inside and outside of the cell)

Dynamic structure which alters to facilitate cellular requirements

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13
Q

phospholipid

A

Polar hydrophilic head (water loving)

Derived from glycerol conjugated to nitrogenous compounds

Non polar hydrophobic tail (water fearing)

Two long chain fatty acids

One fatty acid is saturated (straight) which the other is unsaturated (kinked)

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14
Q

Bilayer

A

Spontaneously forms a bilayer with hydrophilic heads faced outwards and hydrophobic tails forced inwards together

Structure is relatively weak and will separate if sufficient force is placed

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15
Q

cholesterol

A

Fills the gaps between unsaturated fatty acid tails

Stabilise and regulate the fluidity of the phospholipid bilayer

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16
Q

Proteins

A

Functional units within the plasma membranes

Integral proteins: incorporated within the membrane goes through both sides of the membrane

Transport channels or carriers

Enzymes

Receptors i.e. detects interactions with hormones

Peripheral proteins: embedded within the inner or outer surface

Cell recognition and cell to cell interactions i.e. glycoproteins

Cytoskeleton anchorage facilitates shape and placement of particular proteins

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17
Q

membrane junctions determined by?

A

Glycoproteins (glue like)

Wavy contours of the membrane (tongue and groove)

Special cell junctions

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18
Q

Desmosomes

A

Disk-shaped junctions that form cells into tissue

Found in areas that can be stretched prevents tearing due to arrangement of protein filaments i.e. found in organs subject to mechanical stress – heart

Due to cross-linkage of proteins which are densely accumulated at the cytoplasmic surface of each cell and in the extracellular space between cells

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19
Q

Tight Junctions

A

The joining of the extracellular surfaces of two adjacent cells

Occurs in a band around the entire circumference of the cell

Blocks extracellular pathway between cells impermeable

Found in epithelial cells in the intestinal tract keeps enzymes and microbes from the blood

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20
Q

Gap junction

A

Protein channels linking the cytosol of adjacent cells

Attached to each other via hollow cylinders connexons

-Composed of transmembrane proteins

Allow small molecules to pass through ions, simple sugars

Found in variety of cell types i.e. cardiac cells and smooth muscle

-Present in electrical excitable tissue where ion passage between cells enables synchronisation of their electrical activity and contraction

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21
Q

interstitial fluid

A

a solution which bathes and surrounds cells

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22
Q

interstitial fluid characteristics

A

main component of extracellular fluid containing hormones, fatty acids, amino acids, vitamins, neurotransmitters, hormones, sugars and wastes

Cells must be able to attain the correct balance of components for appropriate function

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23
Q

passive transport

A

No energy required

Diffusion or osmosis

Down concentration gradients to achieve equilibrium

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24
Q

Active transport

A

Requires energy (ATP)

Low high concentration against the gradient

Requires carrier proteins which combine specifically with the transport substance

-Phosphorylation of the protein facilitates movement

-E.g. hydrogen, sodium, potassium

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25
Q

when is bulk transport used

A

Substances which cannot be moved across the plasma membrane moved by bulk transport

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26
Q

Endocytosis

A

Bulk transport into the cell

Cell membrane extends outwards and surrounds particles outside of the cell

Forms a vesicle and can be released inside the cytoplasm

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27
Q

Exocytosis

A

Bulk transport out of the cell

Particles are transported in a vesicle to the cell membrane

Vesicle and cell membrane fuse together releasing the contents

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28
Q

what does diffusion depend on?

A

Diffusion depends on: molecule, size, charge, solubility and kinetic energy of the particles involved

29
Q

Simple Diffusion

A

Non-polar or lipid molecules diffuse directly through the plasma membrane

30
Q

Channel mediated facilitated diffusion

A

Transmembrane channels (proteins) facilitate diffusion via water filled channels

Selective depending on channel size and charge

Leak channels always open allowing movement according to concentration gradients

Chemically gated channels chemically/ligand gated channels open when the appropriate chemical binds

Voltage gated channels open and close in response to changes in membrane potential

Mechanical gated channels open in response to deformation of membrane i.e. via sensory receptors

31
Q

Carrier mediated facilitated diffusion

A

Transmembrane proteins (carriers) transport certain polar molecules which are too large

Alteration in the shape of the channel facilitate movement

32
Q

Factors affecting the rate of diffusion

A

Size of the chemical substance (smaller = faster)

Temperature (hotter = faster)

Difference in concentration (larger difference = faster)

33
Q

Osmosis

A

Passive transport of water from low solute concentration to high solute concentration

34
Q

Osmolarity

A

the number of solute particles present in a 1L of solution (~300 mOsmol/L in our cells)

i.e. 1 M NaCl = 2 Osmol/L solution depends on the dissociation of the solute

35
Q

Tonicity

A

the ability of a solution to change the shape or tone of cells by altering the cells internal water volume

36
Q

isotonic

A

solutions which have the same number of molecules, or the same osmolarity as our cells

Cells retain normal shape due to no fluid movement

37
Q

Hypertonic

A

solutions which have a higher number of molecules than those seen in the cell

Cells shrink/crenate

38
Q

Hypotonic

A

he solution is more dilute than those in the cells

Cells swell/lyse

39
Q

ATP

A

Adenosine Triphosphate

Glucose, fatty acids and amino acids are sources of energy for ATP synthesis

Production: Metabolic pathways

-Product of one enzyme reaction becomes the substrate for the next

-Inefficient -> Heat is bi-product

ATP-ADP cycle (occurs within mitochondria)

-When bonds are broken, energy is released

———–ATP -> ADP + Pi + energy

———–Faciliated through ATPase

40
Q

Glycolysis (anaerobic)

A

The breakdown of 6-carbon glucose into two 3-carbon pyruvic acid units

The hydrogens removed join with the hydrogen carrier NAD+ to form NADH

Although some energy is needed to start glycolysis, there is an overall net gain of 2 ATP

Occurs in the cytoplasm

41
Q

Krebs Cycle

A

Pyruvate moves into the mitochondria

Pyruvic acid Acetyl CoA produces NADH as a by-product

2 Acetyl CoA produced per glucose i.e. 1 Acetyl CoA per pyruvate molecule

FADH2 is also produced

NAD and FAD are carrier molecules that transport hydrogen atoms and electrons

1 ATP produced per Acetyl CoA

42
Q

Electron Transport Chain

A

High energy electrons help pump H+ across the inner mitochondrial membrane creating a concentration gradient

ATP synthase – site of ATP production H+ flow through, capturing energy

Hydrogen combines with oxygen to form water

43
Q

Aerobic respiration

A

Aerobic: with O2

The presence enables pyruvic acid acetyl CoA

44
Q

Anaerobic

A

Anaerobic: without O2

Undergoes purely glycolysis

Production of NADH ‘clogs’ up glycolysis

Pyruvic acid Lactic acid which enables NADH to provide its electrons to it

Lactic acid build-up causes pain

45
Q

Paracrine/Autocrine

A

Local communication:

Paracrine: Adjacent or close cells

Autocrine: Same cell

-Involved in positive feedback loops to perpetuate a response

46
Q

Hormones

A

Part of the endocrine system:

Slow but long lasting

Long range chemical messengers

The blood carries the messenger to other sites in the body, where they exert their effects on their target cells some distances from their site of release.

Only the target cells of a particular hormone have receptors

47
Q

Neurotransmitter

A

Nervous System:

Short range chemical messengers

Secreted at synapse

Exerts effects dendrites of post-synaptic neuron or neuromuscular junction (muscle cell)

Fast-response

Short lasting because cleared by reuptake, enzyme degeneration

Prevents any unwanted signals

Excitatory or inhibitory

48
Q

Control of hormones release

A

Hormone release results from gland stimulation, however patterns may vary
-Spurts
-Evenly
-Sporadically as needed

Controlled by:
-Humoral stimuli (chemical changes in blood nutrients, iron levels)
-Neural Stimuli (nerve fibres stimulates glands)
-Hormonal stimuli (can attach to a gland, which triggers to release another hormone)

 

49
Q

compare hormones and neurotransmitters based on duration, speed of response, transport and clearance

A

duration
hormone= prolonged
Neurotransmitter=immediate

Speed of response
Hormone= slow
Neurotransmitter=fast

Transport
Hormone= blood stream
Neurotransmitter= across synapse

Clearance
Hormones= Enzyme degradation
Neurotransmitter= Reuptake/diffusion

50
Q

Epithelial tissue

A

A sheet of cells that covers a body surface or lines a body cavity – form body boundaries

Function: protection, absorption, filtration, excretion, secretion – defends on structure

Forms in the body;

51
Q

Covering and lining epithelium

A

Covering and lining epithelium: forms the outer layer of the skin, dips into and lines the open cavities of the urogenital, digestive and respirator systems and covers the walls and organs of closed ventral body cavity

52
Q

Granular epithelium

A

Glandular epithelium: surrounds the glands of the body

53
Q

Main characteristics of epithelium tissue

A

polarity, specialised contacts, supported by connective tissue, Avascular and innervated, regeneration, simple or stratified

54
Q

Polarity

A

Polarity: all epithelia have an apical (top) surface and a lower attached basal (bottom) surface that differ in structure and function

Apical sections often have microvilli (small extensions which increase SA) or motile cilia (slender protuberances that beat in waves)

55
Q

Specialised contacts

A

Specialised contacts: epithelial cells fit close together and form continuous sheets tight junctions and desmosomes

56
Q

Support by connective tissue

A

Supported by connective tissue: reinforces the epithelium and helps resist tearing and stretching

57
Q

Avascular and innervated

A

Avascular and innervated: no blood tissues but supplied by nerve fibres

Nourished by diffusion of nutrients from blood vessels in underlying connective tissue

58
Q

Regeneration

A

Regeneration: regenerative capacity given adequate nutrition

Classification of Epithelia: (number of cell layers) (cell shape)

59
Q

simple or stratified

A

Simple or stratified (2 or more layers): simple for absorption and filtration and stratified for durability and protection

60
Q

Connective tissue

A

Tissue that connects, supports, binds or separates other tissues or organs

Highly vascular with exception of cartilage

61
Q

What are the three main components of connective tissue?

A

Ground substances(clear, colourless, viscous fluid that fills the space between the cell and fibres

Fibres

Cells
–Ground substances+fibres= extracellular matrix
–composition of each component differs in different tissues resulting in versatility

62
Q

What are the three types of fibres

A

collagen. elastic and reticular

63
Q

Collagen

A

Collagen: fibrous protein – extremely tough and provides high tensile strength

Cross link and bundle together into thick fibres

64
Q

Elastic

A

Elastic: long thin fibres (elastin) which form branching networks which allow stretching and recoil

65
Q

Reticular

A

Reticular: short, fine collagenous fibres which branch extensively to form a delicate network

Important around other tissue types – form fuzzy nets which allow more ‘give’ than collagen

66
Q

Specific cell types

A

-blast, -cyte fat cells
-blast immature, non-differentiated cells

Actively proliferating and secrete the ground substance and the fibres characteristic of their particular matrix

-cyte mature

Maintain the health of the matrix

Can revert to their active/immature state to repair and regenerate the matrix

Fat cells: store nutrients

67
Q

Muscle Tissue

A

Make ~50% of body mass

Cardiac muscle: contracts the heart to pump blood

Skeletal muscle: moves bones and other structures

Smooth muscle: changes shape to facilitate bodily functions

Characteristics

68
Q

Nervous Tissue

A

Nervous tissue is found in the central and peripheral nervous systems

The brain, spinal cord and nerves

Regulates and controls body function

Well vascularised (supplied by blood vessels)

69
Q

Simple squamous

A

DSA (4 decks)

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