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IB BIO > Unit 1 - Cell Biology > Flashcards

Unit 1 - Cell Biology Flashcards

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1
Q

Cell Theory

A

1- all living things are composed of cells
2- the cell is the smallest unit of life
3- cells only arise from pre-existing cells

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2
Q

All living things carry out 7 basic functions integral to survival
MR SHENG

A

M: metabolism - living things undertake essential chemical reactions
R: reproduction - living things produce offspring, either sexually or asexually
S: sensitivity - living things are responsive to internal and external stimuli
H: homeostasis - living things maintain a stable internal environment
E: excretion - living things exhibit the removal of waste products
N: nutrition - living things exchange materials and gases with the environment
G: growth - living things can move and change shape or size

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3
Q

[unicellular organisms]

Paramecium (heterotroph)

A

surrounded by small hairs called cilia allowing it to move - responsiveness
engulf food via specialized membranous feeding groove called cytostome - nutrition
food particles are enclosed within small vacuoles that contain enzymes for digestion - metabolism
solid wastes are removed via an anal pore and liquid waste pumped out via contractile vacuoles - excretion
essential gases enter (O2) and exit (CO2) the cell via diffusion - homeostasis
divide asexually (fission) although horizontal gene transfer can occur via conjugation - reproduction

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4
Q

[unicellular organisms]

Scenedesmus (autotroph)

A

exchange gases and other essential maters via diffusion - nutrition, excretion
chlorophyll pigments allow organic moecules to be produced via photosynthesis - metabolism
daughter cells form as non-motile autospores via the internal asexual division of the parent cell - reproduction
may exist as unicells or form colonies for protection - responsiveness

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5
Q

The rate of metabolism of a cell is a function of its ____/____

A

mass/volume

larger cells need more energy to sustain essential functions

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6
Q

The rate of material exchange is a function of its ______

A

surface area

large membrane surface equates to more material movement

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7
Q

as a cell grows, volume increases _____ than surface area, leading to a ______ SA:V ratio

A

faster/decreased

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8
Q

Calculation of magnification

A

M = Image size / Actual size

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9
Q

Calculation for actual size

A

A = Image size / Magnification

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10
Q

Features of a Bacteria (e. Coli) under microscope

A

Cell wall
Flagella
approx. 1 - 10 um

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11
Q

Features of a Protist (amoeba) under a microscope

A

Nucleus
Pseudopodia
Food vacuoles
approx. 50 - 500 um

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12
Q

Features of a Plant cell (leaf) under a microscope

A

Nucleus
Chloroplasts
Cell wall
approx. 10 - 100 um

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13
Q

Features of an Animal cell (cheek) under a microscope

A

Nucleus
Mitochondria
approx. 10 - 50 um

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14
Q

Specs of multicellular organisms

A

Cells may be grouped together to form tissues
Organs are then formed from the function of grouping of multiple tissues
Organs that interact may form organ systems capable of carrying out specific body functions
Organ systems collectively carry out the life functions of the complete organism

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15
Q

Organisation of multicellular organisms

A

muscle - cardiac - heart - vascular - human
and respectively
cell - tissue - organ - system - organism

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16
Q

Differentiation

A

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

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17
Q

All cells of an organism share an _______ ________

A 
identical genome 
(each cell contains the entire set of genetic instructions for that organism)
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18
Q

Gene packing

A

Within the nucleus of a eukaryotic cell, DNA is packaged with proteins to form chromatin

  • active genes are usually packaged in an expanded form called euchromatin that is accessible to transcriptional machinery
  • inactive genes are typically packaged in a more condensed form called heterochromatin (saves space not transcribed)
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19
Q

Stem Cells

A

unspecialised cells that have two key qualities

  • self renewal: the can continuously divide and replicate
  • potency: they have the capacity to differentiate into specialised cell types
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20
Q

Types of Stem Cells

A

Totipotent - can form any cell type, as well as extra embryonic (placental) tissue (e.g. zygote)
Pluripotent - can form any cell type (e.g. embryonic stem cells)
Multipotent - Can differentiate into a number of closely related cell types (e.g. haematopoeitic adult stem cells)
Unipotent- can not differentiate, but are capable of self renewal (e.g. progenitor cells, muscle stem cells)

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21
Q

Totipotent

A

Oocyte sperm, Morula, Blastocyst

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22
Q

Pluripotent

A

inner mass cells

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23
Q

Multipotent and Unipotent

A

Digestive tissue, nervous tissue, cardiac tissue

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24
Q

Uses for Stem Cells

A

Necessary for embryonic development as they are an undifferentiated cell source for which all other cell types may be derived
Cell types that are not capable of self renewal (e.g. amitotic nerve tissues) are considered to be non-stem cells
viable therapeutic option when these tissues become damaged

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25
Q

Prokaryotes have a _____ cell structure ______ compartmentalisation

A

simple/without

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26
Q

Eukaryotes have a _______ cell structure

A

compartmentalised

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27
Q

Prokaryotes divide by ______

A

binary fission - asexual reproduction

28
Q

Binary Fission

A

circular DNA is copied in response to a replication signal
The two DNA loops attach to the membrane
The membrane elongates and pinches off (cytokinesis), forming two cells

29
Q

Ribosomes

A

Structure: two subunits made of RNA and protein, larger in eukaryotes (80s) than prokaryotes (70S)
Function: site of polypeptide synthesis (translation)

30
Q

Cytoskeleton

A

Structure: a filamentous scaffolding within the cytoplasm
Function: provides internal structure and mediates intracellular transport (less developed in prokaryotes)

31
Q

Plasma Membrane

A

Structure: Phospholipid bilayer embedded with protiens (not an organelle - vital structure)
Function: Semi-permeable and selective barrier surrounding the cell

32
Q

Nucleus

A

Structure: Double membrane structure with pores: contains an inner called nucleolus
Function: stores genetic material (DNA) as chomatin

33
Q

Nucleolus

A

Structure: inside nucleus
Function: site of ribosome assembly

34
Q

Endoplasmic Reticulum

A

Structure: a membrane network that may be bare - smooth ER or studded with ribosomes - rough ER
Function: transport materials between organelles
smooth - lipids
rough - proteins

35
Q

Golgi Apparatus

A

Structure: An assembly of vesicles and folded membranes located near the cell membrane
Function: involved in the sorting, storing, modification and export of secretory products

36
Q

Mitochondrion

A

Structure: double membrane structure, inner membrane highly foled into internal cristae
Function: site of aerobic respiration (ATP production)

37
Q

Peroxisome

A

Structure: membranous sac containing a variety of catabolic enzymes
Function: catalyses breakdown of toxic substances and other metabolites

38
Q

Centrosome

A

Structure: microtubule organising centre (in animal cells - paired centrioles)
Function: radiating microtubules form spindle fibres and contribute to cell division (mitosis and meiosis)

39
Q

Chloroplast

A

(plant cell only)
Structure: double membrane structure with internal stacks of membranous discs (thylakoids)
Function: site of photosynthesis - manufacture organic molecules are stored in various plastids

40
Q

Vacuole

A

(plant cell only)
Structure: fluid-filled internal cavity surrounded by a membrane
Function: maintains hydrostatic pressure (animal cells may have small and temporary ones)

41
Q

Cell Wall

A

(plant cell only)
Structure: external out covering made of cellulose (vital structure not ‘organelle’)
Function: provides support and mechanical strength; prevents excess water uptake

42
Q

Lysosome

A

(animal cell only)
Structure: membranous sacs filled with hydrolytic enzymes
Function: breakdown / hydrolysis of macromolecules

43
Q

The phosopholipid bilayer is held together by _____ hydro______ interactions between the ______

A

weak/phobic/tails

44
Q

Integral proteins

A

are premanently attached to the membrane and are typically transmembrane (span across the membrane)

45
Q

Peripheral proteins

A

are temporarily attached by non-covalent interactions and associate with one surface of the membrane

46
Q

Membrane Protein key functions

A

JET RAT
J: junctions - connect and join two cells
E: enzymes - fixing to membranes localises metabolic pathways
T: transport - responsible for facilitated diffusion and active transport
R: recognition - markers for cellular identification
A: anchorage - attachment points for cytoskeleton and extracellular matrix
T: transduction - receptors for peptide hormones

47
Q

Cholesterol component of ______ cells, where it functions to maintain mechanical stability

A

animal

where the plant cell lacks this, it has cellulose in the rigid cell wall

48
Q

Cholesterol interacts with the fatty acid tails of phosopholipids to moderate the properties of the membrane:

A

Immobilise the outer surface of the membrane - reducing fluidity
Less permeable to very small water-soluble molecules that would otherwise freely cross
Seperate phospholipid tails and so prevent crytallisation of the membrane
Secure peripheral protiens by forming high density lipid rafts capable of anchoring the protien

49
Q

Components of the Plasma Membrane

A

Phospholipids - form a bilayer with phosphate heads facing outwards and fatty acid tails facing inwards
Cholesterol - found in animal cell membranes and functions to improve stability and reduce fluidity
Protiens - may be either intergral (transmembrane) or peripheral and serve a variety of roles

50
Q

Cellular Membranes possess two key qualities

A

semi-permeable

and selective - membrane proteins may regulate the passage of material that connot freely cross

51
Q

Passive Transport - involves the movement of material _____ a concentration gradient. Since it is moving _____ the concentration gradient it requires ____ energy
Three main types of passive transport:

A

along/down/no
Simple diffusion
Osmosis
Facilitated diffusion

52
Q

Simple Diffusion

A

movement of small or lipophilic molecules (O2, CO2)

53
Q

Osmosis

A

movement of water water molecules (dependent on solute concentrations)

54
Q

Facilitated Diffusion

A

movement of large or change molecules via membrane protiens (ie. ions, sucrose)

55
Q

Active Transport invloves the movement of materials _____ a concentration gradient. Since the materials are moving ______ the concentration gradient it requires _____ energy
There are two main types of active transport:

A

against/against/some
Primary (direct)
Secondary (indirect)

56
Q

Primary (direct) active transport

A

involves the direct use of metabolic energy (ATP hydrolysis) to mediate transport

57
Q

Secondary (indirect) active transport

A

involves coupling the molecule with another moving along an electrochemical gradient

58
Q

Hypertonic solutions the water will ____ the cell causing it to _____

A

leave/shrivel

59
Q

Hypotonic solutions water will _____ the cell causing it to _____ and potentially ____

A

enter/swell/burst

60
Q

Active transport uses carrier protiens (called protien pumps due to their use of energy)

A

a specific solute will bind to the protein pump on one side of the membrane
the hydrolysis of ATP - ADP + Pi causes conformational change in the protein punp
the solute molecule is consequently transloacted across the membrane (against the gradient) and released

61
Q

Sodium Potassium Pump - an integral protein that exchanges ____ sodium ions (moves out of the cell) with ___ potassium ions (moves into the cell)

A

three/two

62
Q

Vesicular Transport - three organelles that part take in this?

A 
Endoplasmic Reticulum - materials are transported from the ER when the membrane bulges and then buds to create a vesicle surrounding the material 
Golgi Apparatus - material stored within the golgi apparatus will either be secreted externally or may be transported to the lysosome 
Plasma Membrane (vesicles containing materials destined for extracellular use will be transported to the plasma membrane) - the vesicle wil fuse with the cell membrane and its materials will be expelled into the extracellular fluid
63
Q

Endocytosis process by which large substances (or bulk amounts of smaller substances) _____ the cell _____ crossing the membrane

A

enter/without

64
Q

Two main types of endocytosis

A

Phagocytosis - the process by which solid substances are ingested (usually transported to the lysosome)
Pinocyotosis - the process by which liquids/ dissolved substances are ingested (allows faster entry than via protien channel)

65
Q

Exocytosis - the process by which large substances (or bulk amounts of smaller substances) ____ the cell ______ crossing the membrane

A

exit/without

66
Q

Processes of exocytosis

A

vesicles (typically derived from the golgi) fuse with the plasma membrane, expelling their contents into the extracellular environment

adds vesicular phospholipids to the cell membrane, replacing those lost when vesicles are formed via endocytosis

67
Q

_______ and ______ are both organelles suggested to have arisen via endosymbiosis

A

mitochondria/chloroplasts

IB BIO (2 decks)

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