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Biology Topic 1: Cell Biology > topic 1.1 - 1.4 > Flashcards

topic 1.1 - 1.4 Flashcards

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1
Q

Rules of the cell theory

A
  1. living organisms are composed of cells
  2. cells are the smallest units of life
  3. cells come from pre-existing cells
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2
Q

cell theory exceptions

A

Unicellular organisms:
- they carry out all functions of life (metabolism, growth, reproduction…etc)
- they use cell division for reproduction (binary fission)

Viruses:
- not cellular (acellular)
- they are only made with DNA/RNA surrounded by a protein coat
- They don’t carry out functions of life

Skeletal muscle cells:
- muscles are made out of muscle fibres - and these contain hundreds of nuclei
- much larger than normal cells

Hyphae:
- these are thread-like structures in fungi with a cell membrane and cell wall.
- they often contain nuclei without dividing walls between them

Extra cellular matrix:
- many tissues contain extra cellular matrix- material outside the cell membrane such as plant cell wall, bone

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3
Q

characteristics of viruses

A
  • viruses are acellular
  • they are intracellular parasites
  • they are considered non-living as they do not perform: metabolic activities, reproduction on their own, homeostasis, and nutrition
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4
Q

formula used to calculate magnification

A

Magnification = size of drawing / actual size

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5
Q

functions of life

A

Metabolism – The regular set of life-supporting chemical reactions that takes place within the cells of living organisms.

Growth – An increase in size or shape that occurs over a period of time.

Response (to a stimulus) – A reaction by the living organism to changes in the external environment.

Homeostasis – The maintenance of a constant internal environment by regulating internal cell conditions.

Nutrition – The intake of nutrients, which may take different forms in different organisms. Nutrition in plants involves making organic molecules (during photosynthesis), while nutrition in animals and fungi involves the absorption of organic matter.

Reproduction – The production of offspring, either sexually or asexually, to pass on genetic information to the next generation.

Excretion – The removal of waste products of metabolism and other unimportant materials from an organism.

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6
Q

surface are to volume ratio information

A
  • as cell size increases, surface area and volume increase
  • as cell size increase the surface area: volume ratio decreases
  • the rate of heat production/ waste production/ resource consumption of a cell is a function of its volume
  • the rate of exchange of materials and energy (heat) is a function of its surface area
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7
Q

what happens of a cell grows too big?

A
  • distance from the centre of the cell to membrane is greater, therefore it takes longer for nutrients to reach it.
  • the diffusion rate becomes too slow to support cell function and its needs.
  • cannot absorb nutrients and oxygen fast enough
  • cannot excrete waste products such as carbon dioxide fast enough.
  • heat is not lost quickly enough
  • large cells become structurally weaker
  • some cells are adapted to increase their SA:volume ratio
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8
Q

structure of a prokaryotic cell (bacteria)

A
  • cytoplasm
  • plasmids
  • cell wall
  • slime capsule
  • pili (pilus)
  • mesosome
  • plasma membrane
  • flagellum
  • 70s ribosomes
  • genetic material
  • photosynthetic membrane (found in some bacteria)
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9
Q

structure of eukaryotic plant cell

A
  • cell wall
  • plasma membrane
  • mitochondrion
  • smooth ER
  • rough ER
  • plasmodesmata
  • nucleus
  • 80s ribosomes
  • cytoplasm
  • chloroplasts
  • permanent vacuole
  • golgi apparatus
  • vesicles
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10
Q

structure of eukaryotic animal cell

A
  • plasma membrane
  • microtubials
  • 80s ribosomes
  • nucleolus
  • nucleus
  • rough ER
  • smooth ER
  • mitochondria
  • microphilaments
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11
Q

function of plasma membrane

A

controls the movement of substances in and out of the cell

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12
Q

function of cytoplasm

A

fill the cell and holds all organelles. it also contains enzymes that catalyse various reactions occurring in the cytoplasm.

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13
Q

function of mitochondria

A

a site of cellular respiration in which ATP is generated

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14
Q

function of 80s ribosomes

A

the sites of protein synthesis. free ribosomes produce protein used inside the cell itself

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15
Q

function of nucleus

A

controls all the activities of the cell, as well as the reproduction of unicellular organelles

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16
Q

function of nucleolus

A

part of the nucleus which is involved in the production of ribosomes

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17
Q

function of smooth endoplasmic reticulum (ER)

A

responsible for producing and storing lipids including steroids.

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18
Q

function of rough endoplasmic reticulum (ER)

A

transport the protein produced by ribosomes on its surface to the golgi apparatus. these proteins are usually for use outside of the cell.

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19
Q

function of golgi apparatus

A

processes and packages proteins, which are ultimately released in the golgi vesicle

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20
Q

function of vesicle

A

a small sac that transports and releases substances produced by the cell by fusing with the cell membrane

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21
Q

function of lysosomes (only in animal cells)

A

contains hydrolytic enzymes and plays important roles in the destruction of microbes engulfed by white blood cells, as well as in the destruction of old cellular organelles.

22
Q

function of centrioles (only in animal cells)

A

plays an important role in the process of nuclear division by helping to establish the microtubules

23
Q

function of cell wall (only in plant cells)

A

protects the cell, maintains its shape, and prevents it from bursting in hypotonic media.

24
Q

function of chloroplasts (only in plant cells)

A

these are double membrane-bound organelles. They contain pigments that are responsible for photosynthesis.

25
Q

function of cytoskeleton

A

provides internal structure and meditates extracellular transport

26
Q

what makes up the cytoskeleton?

A

microfilaments and microtubules

27
Q

what is compartmentalisation?

A

this refers to the formation of compartments within the cell by membrane bound organelles.

28
Q

advantages of cells being compartmentalised

A
  • greater efficiency of metabolism as enzymes are enclosed, and therefore much more concentrated
  • internal conditions such as pH can be differentiated in a cell to maintain the optimal conditions for different enzymes.
  • isolation of toxic or damaging substances away from the cytoplasm
  • flexibility of changing the number and position of organelles within the cell based on the cell’s requirements.
29
Q

relationship between R.E.R., golgi apparatus, and vesicles

A

proteins are made by ribosomes embezzled into the RER membrane and vesicles bud off the RER and carry the proteins to the Golgi apparatus. these proteins are processes and packaged in the golgi and finally, the vesicles bud off golgi and release the final protein to the outside of the cell.

30
Q

components of the plasma membrane

A

all biological membranes are composed mainly of lipids and protein molecules.

31
Q

3 major types of lipids in cell membranes

A
  • phospholipids - most abundant
  • cholesterol
  • glycolipids
32
Q

structure of phospholipids

A
  • polar phosphate and glycerol head group that is hydrophilic
  • two non-polar fatty acid tails bonded to the head group are hydrophobic
33
Q

phospholipid bilayer

A

As the lipids group together, they form bilayers with the fatty acid chains positioned towards the non-aqueous interior and the polar heads in contact with the water

34
Q

cholesterol

A

found in animal cell membranes and functions to improve the stability and reduce fluidity of the membranes

35
Q

characteristics of cholesterol

A
  • cholesterol is amphipathic
  • the hydroxyl group end o cholesterol aligns with the phospholipid heads
  • the remainder embeds itself in the bilayer between the phospholipid tails, adding stability to the membrane
  • it is a steroid
36
Q

permeability

A

The property of membranes that permits movement across their surface

37
Q

high to low permeability

A

hydrophobic molecules, small uncharged polar molecules, ions (only through a protein channel or carrier)

38
Q

diffusion

A

the passive random net movement of a substance from an area of high concentration to an area of low concentration

39
Q

types of transports across membranes

A
  • simple diffusion
  • facilitated diffusion: channels or carriers
  • osmosis
  • active transport: protein carrier
  • bulk transfer
40
Q

simple diffusion

A
  • occurs in gases or liquids and only requires a concentration gradient
  • if particles are too big, they cannot pass through the bilayer
41
Q

facilitated diffusion

A
  • requires channel proteins or carrier proteins to move from high to low concentration
  • the channels and carriers are specific to the molecules being transported
42
Q

osmosis

A
  • form of diffusion that involves water molecules
  • water molecules move from through a partially permeable membrane from a side of higher concentration to a lower concentration till equilibrium is reached.
43
Q

bulk transport

A

endocytosis: The process by which large substances (or bulk amounts of smaller substances) enter the cell without crossing the membrane

exocytosis: The process by which large substances (or bulk amounts of small substances) exit the cell without crossing the membrane

44
Q

Emergent properties

A

Emergent properties arise when the interaction of individual component produce new functions

45
Q

organisation of multicellular organisms

A

cells - tissues - organs - systems - organism

46
Q

cell differentiation

A

Differentiation is the process during development whereby newly formed cells become more specialised and distinct from one another as they mature

All cells of an organism share an identical genome – each cell contains the entire set of genetic instructions for that organism

The activation of different instructions (genes) within a given cell by chemical signals will cause it to differentiate

47
Q

who proposed a model whereby two layers of protein flanked a central phospholipid bilayer

A

Danielli and Davson

48
Q

new model of membrane structure

A

Singer and Nicolson
According to this model, proteins were embedded within the lipid bilayer rather than existing as separate layers

49
Q

active transport

A

Active transport involves the movement of materials against a concentration gradient (low concentration ⇒ high concentration)

Because materials are moving against the gradient, it requires the expenditure of energy (e.g. ATP hydrolysis)

50
Q

passive transport

A

Passive transport involves the movement of material along a concentration gradient (high concentration ⇒ low concentration)

51
Q

Osmolarity

A

Osmolarity is a measure of solute concentration, as defined by the number of osmoles of a solute per litre of solution

Biology Topic 1: Cell Biology (1 decks)

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