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year 1 random Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

what is diffusion?

A

the net movement of particles from a region of higher concentration to a region of lower concentration. it continues until movement is equal in both directions (equilibrium)

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2
Q

factors affecting the speed of diffusion

A

temperature
distance
difference in concentration
surface area

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3
Q

why would temperature decrease speed of diffusion

A

particles moving at high speeds are constantly colliding which slows down their overall movement. The more collisions that take place the slower the rate of diffusion.

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4
Q

what is facilitated diffusion

A

diffusion through protein channels in the membrane. involves movement down a concentration gradient (passive transport)

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5
Q

what is the phospholipid bilayer a barrier to without channel proteins

A

polar molecules and ions

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6
Q

what is facillitated diffusion affected by

A

affected by all factors which affect simple diffusion alongside the number of channel proteins present

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7
Q

what is endocytosis

A

the process of substances entering the cell via bulk transport

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8
Q

what is the process of endocytosis (step by step)

A
  1. cell surface bends inwards when comes into contact with material to be transported
  2. membrane enfolds the material until membrane fuses
  3. this forms a vesicle
  4. vesicle moves into cytoplasm and detached from membrane to transfer material for further processing eg bacteria to lysosomes
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9
Q

what ways can molecules move across membranes

A 
simple diffusion 
facilitated diffusion 
osmosis (water only)
bulk transport (endo/exocytosis)
active transport (against a concentration gradient)
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10
Q

what roles do cell membranes have

A

separate contents of cells from the surrounding environment

separate different areas within cells from each other
allow for compartmentalisation which allows for different potentially incompatible reactions to take place at the same time

allows to set up specific conditions for specific cellular reactions

allow chemical gradients to be maintained

protect vital cell components

allow for efficient cell communication

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11
Q

define what is meant by the term organ

A

a collection of tissues adapted to perform a particular function eg heart

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12
Q

define what is meant by the term tissue

A

made up of a collection of differentiated cells which have specialized functions. each tissue is adapted for a particular function within an organism.

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13
Q

define what is meant by an organ system

A

composed of a number of organs working together to carry out a major body function eg digestive system

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14
Q

describe chromatin

A

DNA accessible for transcription so genetic info can be translated
DNA usually packed loosely within nucleus
found in all non dividing cells in process of interphase

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15
Q

what are chromosomes

A

DNA that is easily segregated and transported without damage
the DNA cannot be transcribed
temporary packaging of tightly wound and condensed DNA.

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16
Q

what are homologous chromosomes

A

the same size
contain the same genes
contain sister chromatids

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17
Q

what is exocytosis

A

the bulk transport of substances out of the cell

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18
Q

what is the process of exocytosis (step by step)

A

vesicles are formed with material inside
vesicles move towards the plasma membrane to fuse with it
the contents of the vesicle are released to the outside of the cell

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19
Q

what is bulk transport

A

a form of ACTIVE TRANSPORT. large molecules and whole cells are too large to move through channel or carrier proteins so move in or out of the cell via bulk transport.

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20
Q

describe the step by step process of active transport when using a carrier protein

A
  1. the molecule to be transported binds to receptors in the channel of the carrier protein on the outside of the cell
  2. on the inside of the cell ATP binds to carrier protein and is hydrolysed into ADP and inorganic phosphate
  3. phosphate binds to carrier protein thus changing the proteins shape , opening up to the inside of the cell
  4. molecule released to inside of cell
  5. phosphate molecule released and recombined with ADP to form ATP
  6. carrier protein forms to original shape
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21
Q

describe osmosis

A

passive process
net movement of water from solution with high water potential to a solution of lower water potential down a water potential gradient.
will continue until there is equal movement in both directions (equilibrium)

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22
Q

what ways can a solution be described in relation to a cell

A

solution is either isotonic hypertonic or hypotonic to a cell

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23
Q

define hypertonic

A

solution has a lower water potential outside of the cell can lead to crenation

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24
Q

define hypotonic

A

solution has a higher water potential outside of the cell can lead to cell lysis

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25
Q

define isotonic

A

think lucozade solution has same water potential outside of the cell

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26
Q

What happens at checkpoint G1

A

G1 -nutrient levels growth factors and DNA damage checked if fails goes to G0

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27
Q

what factors effect membrane structure and permeability and how do they do this

A

Temperature when increased phospholipids will have more kinetic energy and thus move more. this increases the membranes fluidity to the point where it starts to loose its structure. at higher temperatures this means the cell can break down completely. there is also an increase in permeability due to the change in tertiary structure of membrane proteins carrier and channel proteins thus become denatured

Solvents water is a polar solvent this allows for interactions that keep the bilayer intact. organic solvents are less polar and will dissolve membranes less concentrated solutions do not dissolve membranes but there presence disrupts the membrane

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28
Q

describe plasma membrane structure

A

phospholipid bilayer forms majority of cell surface membrane. phospholipids have hydrophilic head and hydrophobic tail. hydrophilic heads form inner and outer surface of membrane. hydrophobic fatty acid tails form a hydrophobic core inside the membrane. their are intrinsic and extrinsic proteins within the membrane. the fluid mosaic model models the membranes properties and structure.

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29
Q

what is an adaptation of the plasma membrane structure?

A

phospholipids suited to aqueous environment both inside the cell and outside the cell, this is because hydrophilic heads can interact with water

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30
Q

what are channel proteins?

A

An intrinsic protein
Involves passive transport for polar ions and molecules.
Held in position by interactions between hydrophobic core of plasma membrane and hydrophobic r groups on the outside of proteins.

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31
Q

what are the intrinsic proteins found in the plasma membrane?

A

channel
carrier
glycoproteins
lipids

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32
Q

what are extrinsic proteins?

A

proteins that are only present on one side of the bilayer (usually have hydrophobic r groups on outer surfaces) interact with polar heads or intrinsic proteins. some can move between layers an example would be cholesterol

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33
Q

what are carrier proteins?

A

proteins in plasma membrane which involve both the passive and active transport into cells and change shape in order to let substances in

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34
Q

what are glycolipids?

A

lipids with an attached sugar chain. they act as cell markers like antigens which can be recognised as self and non-self.

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35
Q

what are glycoproteins?

A

proteins with an attached sugar chain. these play a role in cell adhesion and receptors for chemical signals playing a part in cell communication. when a chemical binds to a receptor it causes a direct response or a cascade of events.

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36
Q

what is cholesterol?

A

a lipid with a polar and non polar end it regulates fluidity of membranes, positioned in between phospholipids. cholesterol also adds stability by the polar end interacting with heads while non polar end interacts with tails. this pulls them together without making them too rigid. prevents phospholipid molecules grouping too closely and crystallizing.

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37
Q

what is meant by the fluid mosaic model?

A

it describes the fact that proteins occupy various positions on the membrane and that phopholipids are free to move in their layer relative to each other. the membrane is therefore flexible. proteions are also embedded in the membrane which vary in shape size and position, proteins have to be in particular positions for chemical reactions.

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38
Q

Basic principles of meiosis including interphase

A

In interphase chromosomes replicate
In meiosis 1 homologous chromosomes separate
In meiosis 2 sister chromatids separate
In both meiosis 1 and 2 PMAT is followed

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39
Q

Describe interphase in terms of activity

A 
Chromatin unwinds 
Chromosomes replicate 
Centrioles replicate 
Nucleus present 
Protein synthesis 
Cell growth 
ATP production 
Transcription and translation of DNA
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40
Q

Describe prophase in terms of activity (mitosis)

A

Chromatin condenses coiling to form chromosomes
Can clearly see chromosomes
Nucleus disappears
Spindle fibres attach to centromeres

41
Q

Describe metaphase in terms of activity (mitosis)

A

Chromosomes align at metaphase equator/plate
Nuclear envelope disappears
Spindle fibres attached to centromeres

42
Q

Describe anaphase in terms of activity (mitosis)

A

Sister chromatids separate and move to poles resulting in < shape
Nuclear membrane not present
Spindle fibres contract so pull sister chromatids to opposite poles centromeres divide

43
Q

Describe independent assortment in metaphase 1 meiosis

A

Orientation of each homologous pair is random and independent of other pairs
Maternal and paternal chromosomes can face either pole
The fact that chromosomes could be in any combination in which pole chromosomes are facing is random is known as independent assortment
This results in genetic variation

44
Q

More detail of prophase 1 meiosis key terms
Bivalent
Chiasmata
Recombination

A

Two homologous chromosomes pair up to form a bivalent
Crossing over of genetic material between non sister chromatids can occur at chiasmata where chromatids become entangled
The crossing over results in physical exchange of genetic material and new gene combinations are formed on chromatids this is known as recombination

45
Q

Reasons for mitosis TOAD

A

Tissue repair and replacement

Organism growth so multicellular organisms can derive new cells

Asexual reproduction in plants

Development of embryos from zygotes

46
Q

Reasons for meiosis GERR

A

Genetic variation
Ensures that produced organisms in sexual reproduction have correct number of chromosomes
Repairs genetic defects
Reprograms gametes helping fertilised egg grow

47
Q

Describe telophase and the activity that occurs mitosis

A

Chromatids form into chromosomes at opposite poles
Spindle fibres detach from chromosomes
Nuclear envelope reforms at each pole
Enters cytokinesis forming two identical daughter cells

48
Q

What happens at checkpoint G2

A

G2 -cell size correct replication checked if fails DNA is repaired and cell is allowed to continue growing

49
Q

What happens at metaphase checkpoint

A

Metaphase- chromosome spindle fibre attachment checked if fails waits for spindle fibres to attach to chromatids

50
Q

What happens at G0

A

G0 -non dividing stage cells leave cell cycle entering can be temporary or permanent usually aged damaged or dormant cells re enter but cells that have reached their max differentiation do not re enter the cell cycle
cells enter from G1

51
Q

describe function disadvantage usefulness of a TEM transmission electron microscope

A

function - looking at a thin cross section of an object (eg cell) for looking at internal structure

disadvantage - can’t view living things and is costly

useful for - looking at high resolution objects and relationships between structures

52
Q

describe function disadvantage usefulness of a SEM scanning electron microscope

A

function - looking at the surface of objects at high resolution

disadvantage - costly and cant view living organisms

useful for - looking at objects in 3D and surfaces

53
Q

describe function disadvantage usefulness of a confocal scanning laser microscope

A

function - allows us to look at thon slices of a sample while keeping it intact and label with fluorescence

disadvantage - low resolution only what is fluorescent can be viewed. fluorescences can cause artefacts

useful for - looking at living cells relationships between cells and highlighting individual components

54
Q

what is the function of a vacuole

A

to continue turgor pressure help support and act as a reservoir of waste including salts sugars and pigments

55
Q

describe function disadvantage usefulness of a compound light microscope

A

function - use visible light to illuminate a thin section of sample

disadvantage - lower resolution than electron microscope

useful for - viewing living organisms cells tissues and allows foe an overview of a sample

56
Q

describe key features of a prokaryotic cell

A

No nucleus has a single strand of DNA (circular plasmid)
Can have flagella
Is smaller than eukaryotic cell 0.1 to 10 micrometres
Single celled
Reproduction via binary fission
Organelles not membrane bound

57
Q

describe function disadvantage and usefulness of a light stereomicroscope

A

function - illuminates surface of sample
disadvantage - lower resolution than compound light microscope
useful for - looking at living surfaces

58
Q

what is endosymbiosis explain the process

A

Two independent bacteria
One engulfs the other
One now lives inside the other
Mutualism between the process
Internal bacteria passed on from generation to generation
Bacteria has more potential to become complex due to this process

59
Q

Explain the reproduction of prokaryotes

A

Binary fission
Circular DNA copied in response to replication signal
Two DNA loops attach to the membrane
Membrane elongates allowing for two cells to be formed

60
Q

how can we support the idea that mitochondria were once prokaryotes

A 
Would of existed as an internal bacteria which got passed on and as it did so evolved more complexly 
Mitochondria has 
Double membrane
DNA genome inside 
Similar reproduction process
Not all organelles membrane bound
61
Q

Function of mitochondria

A

Formation of ATP

Provides energy for aerobic respiration within cells

62
Q

Function of a chloroplast

A

Photosynthesises (transfers light into energy)

Has pigment that absorbs light

63
Q

Function of ribosome

A

Protein synthesis

64
Q

Function of plasma membrane

A

Controls exchange between cell and the environment
Selectively permeable
Has receptors for cell recognition and communication

65
Q

Function of nucleus

A

Controls activities of cell
Contains genetic information that can be transmitted to next generation
Involved in transcription

66
Q

overall role filaments and tubules

A 
Provide strength and support to cell
Determine cell shape
Involved in movement of organelles 
Help hold organelles in place
Can make up centrioles and spindle fibres
67
Q

Process of protein synthesis within eukaryotic cell

A

Synthesised via translation of genetic code in the cytoplasm (involves mRNA)
Ribosomes produce the protein
Ribosomes attached to the RER
RER lumen proteins fold up into the correct 3D shape and undergo additions like sugar chains
Transport vesicle created round protein to go to golgi
Golgi apparatus each compartment adds and takes away components modifying the protein
Secretory vesicle out of golgi

68
Q

function of cytoplasm

A

site of chemical reactions

69
Q

function of golgi apparatus

A

Process molecules and proteins
Used in secretion of ^^
Involved in lysosome formation

70
Q

function of cell wall

A

Gives cell its shape strength and support
Prevents cell lysis during osmosis
Fully permeable

71
Q

function of rough ER

A

Protein synthesis via ribosomes attached

Transport of proteins

72
Q

function of smooth ER

A

makes and transports lipids steroids hormones

73
Q

function of nucleolus

A

produces ribosomes

74
Q

key aspects of intermediate filaments

A

Stability main function anchoring organelles
In between microfilaments and microtubules (8-12 nm)
Consist of entwined dimers of various proteins
Add mechanical strength helping to maintain the integrity of cytoskeleton

75
Q

key aspects of microfilaments

A

Provide contractile motion when interact with myosin
Solid
Composed of protein ACTIN
Involved in cytokinesis forming two daughter cells
Support cell movement have FALSE HANDS
Smallest out of IF MT (7nm)

76
Q

key aspects of microtubules

A

Largest out of IF MF (25 nm)
Made up of globular tubulin proteins
Polymerise to form hollow tubes which form a scaffold to determine the shape of a cell (centrioles)
Act as roads for vesicles and organelles
Form hollow tubulin subunits forming cilia flagella and spindle fibres
Help separate chromosomes in cell division

77
Q

describe the cytoskeleton

A

An elaborate network of fine protein filaments
Made of protein filaments and tubules (fibres within the cell)
Helps cells maintain their shape and internal organisation giving an internal framework to the cell
Provides mechanical support enabling cells to carry
out TRANSPORT DIVISION and MOVEMENT
Eukaryotes cytoskeleton consists of MF IF MT

78
Q

What could happen to the protein once in the secretory vesicle (3 paths)

A
  1. transported to plasma membrane vesicle membrane and plasma membrane fuse to perform exocytosis (contents released to extracellular matrix)
  2. vesicle held at plasma membrane to be released upon specific signal
  3. quality control misfolded protein transported to lysosome where digestive enzymes degrade it
79
Q

describe the key features of a eukaryotic cell DORA

A

D - linear
O - has a true nucleus and organelles membrane bound
R - mitosis and meiosis
A - larger than prokaryotic cell 10-100 micrometers
Performs more complex functions like making multicellular organisms

80
Q

function of lysosomes

A

contains digestive enzymes to breakdown undigested material

acts as waste bin/quality control

81
Q

what contains RNA not DNA

A

ribosome

82
Q

structures that can penetrate the walls of adjacent plant cells are called what

A

plasmodesmata

83
Q

what cell structure does not have an envelope

A

mitochondrion

84
Q

what is the purpose of a sucrose solution

A

prevents organelles changing structure via osmosis

85
Q

what organelle always contains DNA

A

mitochondria

86
Q

what would be found in an animal cell undergoing mitosis but not in a plant cell undergoing mitosis

A

centriole

87
Q

interphase G1

A

Increase in cytoplasm volume
Proteins are synthesised for organelle production
Replication of organelles

88
Q

interphase S phase

A

DNA is replicated to produce new set of chromosomes

89
Q

interphase G2

A

Increase in cytoplasm volume
Errors in DNA checked for
Final growth phase before division

90
Q

interphase active phase

A

Preparation for division (won’t be able to see the chromosomes)

91
Q

prophase 2

A

chromosomes condense
nuclear membrane dissolves
centrosomes move to opposite poles (so perpendicular to before)

92
Q

metaphase 2

A

spindle fibres attach to chromatids at centromere aligning at equator of cell

93
Q

anaphase 2

A

spindle fibres contract separating sister chromatids

chromosomes move to opposite poles

94
Q

telophase 2

A

chromosomes decondense
nuclear membrane reforms
cytokinesis occurs to form 4 haploid daughter cells

95
Q

prophase 1

A

chromosomes condense
nuclear membrane dissolved
homologous chromosomes form bivalents (crossing over occurs here)

96
Q

metaphase 1

A

spindle fibres connect to bivalents at centromere

bivalents align along middle of cell in homologous pairs

97
Q

anaphase 1

A

spindle fibres contract splitting bivalents

homologous chromosomes move to opposite poles of cell

98
Q

telophase 1

A

chromosomes decondense
nuclear membrane reform
cytokinesis occurs to produce 2 haploid daughter cells

biology random y1 y2 (2 decks)

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