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IB BIOLOGY 2017 EXAM > Cells > Flashcards

Cells Flashcards

1
Q

Cell Theory

A
  1. All Organisms are composed of one or more cells
  2. Cells are the smallest units of life
  3. All cells from from pre-existing cells
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2
Q

Swan Neck Experiment

A
  • Pasteur sterilized chicken broth by boiling it, showing that living organisms can’t ‘spontaneously’ reappear
  • only after exposure to pre-existing cells did life establish itself in the sterilized chicken broth
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3
Q

Functions of Life

A
  • metabolism
  • reproduction
  • homeostasis
  • excretion
  • growth
  • response
  • nutrition
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4
Q

Paramecium

A
  • a unicellular member of the Protista kingdom

- has all functions of life

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5
Q

Chlorella

A
  • single celled organism with a large chloroplast

- different nutrition approach; uses photosynthesis

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6
Q

Magnification Formula

A
  • size of image/size of specimen
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7
Q

Decreasing order of size

A

organelles–> bacteria–> viruses –> membranes–> molecules

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8
Q

Light microscope

A
  • use light, passing through living or dead specimens, to form an image
  • inexpensive to purchase and operate
  • simple and easy specimen preparation
  • magnifies up to 2000x
  • specimens may be living or dead
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9
Q

electron microscope

A
  • uses electrons passing through a dead specimen to form an image and provide us with the greatest magnifications and resolution
  • expensive to purchase and operate
  • complex and length specimen preparation
  • magnifies over 500 000x
  • specimens are dead; must be fixed in a plastic material
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10
Q

Surface area to volume ratio

A
  • limits the size of the cell
  • the rate of heat/waste production/recource consumption/functions depend on volume (chemical reactions depend on size of cell); a cell with more surface area per unit volume is able to move matierals in and out of the cell
  • as the width of the cell icnreases, the SA increases, but at a slower rate than the volume
  • large cell has less SA needed than small cell; cells limited in size to carry out functions of life
  • larger organisms have MORE cells, not bigger cells
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11
Q

cell size units

A 
micrometer= 1000th of a mm (um)
Nanometer= 1000th of a um (nm)

1mm= 1000 um
1um=100 nm

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12
Q

Differentiation

A

process that results in the expression of certain specific genes but not others, to give a cell a specific function and role (SPECIALIZED) e.g. Nerve and Muscle cells

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13
Q

what does each cell contain

A

the genetic information needed for the production of the complete organism

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14
Q

Stem Cells

A
  • cells that can infinitely divide
  • Usually new cells, found and needed during early life and growth
  • can differentiate into various cell stem cells
  • when stem cells form a specific type of tissue, they also produce daughter cells that say as stem cells
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15
Q

Types of stem cells

A

Embryonic Stem Cells
The primary cells found in an embryo that continuously replicate to form the organs and tissues of a fetus

Somatic Stem Cells
Found in adults, throughout the body. Used for self-renewal and differentiation. Usually can only differentiate to its ‘organ of origin’

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16
Q

what can Stem Cells be used for

A
  • Repair tissue
  • Grow organs
  • Cloning
  • Drugs and treatments
  • Diagnosis of viruses and diseases
  • Sequence all of the human genome
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17
Q

Diseases stem cells could treat

A
  • parkinson’s
  • alzheimers
  • diabetes
  • burn victims
  • Leukima
  • Stargardt’s disease
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18
Q

Parkinsons + alzheimers

A
  • loss of proper functioning brain cells;

stem cells could replaced lost/defective brain cells and relieve symptons

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19
Q

Diabetes

A

stem cells can provide cells in pancreas needed to produce insulin

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20
Q

CANCER (Leukemia)

A
  • stem cells can be used to introduce new blood cells to damaged bone marrow
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21
Q

Stargarts disease

A

STARGARDT’S DISEASE:

  • Inherited
  • Way of processing vitamin A (vision and sight loss)
  • Causes light-sensitive cells in retina to deteriorate: central side and peripheral vision lost
  • STEM CELLS could be used to treat stargardt’s disease by growing the light sensitive cells to make up for the losses
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22
Q

ethical concerns of stem cells

A
  • sanctity of life
  • destroying life: fetus/embryo (however can result in reduction in human suffering)
  • privacy
  • cloning
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23
Q

Prokaryote

A
  • Doesn’t have a definitive nucleus of membrane-bound organelles
  • Single celled organism in which DNA is suspended freely
  • small in size (around 1-10 um)
  • TYPES: 1. Bacteria, 2. Archaea
  • First life form
  • Can be killed by antibiotics
  • Found in every habitat on earth (including digestive system)
  • Divide very quickly
  • Asexual reproduction: binary fission
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24
Q

Features of prokaryotic cell

A
  • cell wall
  • plasma membrane
  • flagella
  • pili
  • ribosomes
  • nucleoid region
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25
Q

Prokaryotic cell wall

A
  • CELL WALL; protects and maintains the shape of thecell; composed of peptidoclycan; some bacteria have additional polysaccaride outisde of cell wall
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26
Q

Prokaryotic membrane

A

plasma membrane; controls movement of matierals into andout of cell + plays a role in binary fission of cell

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27
Q

Prokaryotic cytoplasm

A
  • no compartmentalization of organelles; chemical reactions not isolated from another (limits cell development and efficently)
  • all cellular processes occur in cytoplasm
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28
Q

Pili

A

hair like growths; used for attachment/sensitivity

- join bacterial cells in preperation for DNA transfer from one cell to another

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29
Q

Flagellum

A
  • responsible for cell locomotion (movement)
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30
Q

Prokaryotic ribosomes

A
  • site of protein synthesis

- 70 s size

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31
Q

Nucleoid region

A
  • non-compartmenalized circular thread of DNA

- bacteria also contain plasmids for DNA trasnfer

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32
Q

Binary fission

A
  • prokaryotic cell division; DNA is coppied and two daughter chromosomes become attached to different regions of the plasma membrane and the cell divides into two geneticaly identical daugheter cells
  • divide every 20 minutes
  • DNA FREE: not attached to proteins
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33
Q

Plasmid

A

Can be used for genetic engineering

Foreign dna that can be inserted into bacteria (can make them immune to antibiotics)

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34
Q

EUKARYOTES:

A

EUKARYOTES:
A eukaryote is a microorganism with membrane bound organelles
Organelles: responsible for a specific function critical to the cell’s survival
- 5 to 100 um size

  • plant, animal, algae, protozoa, fungi
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35
Q

organelle

A

a noncellular structure that carries out specific functions

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36
Q

Compartmentilization

A

allows for chemical reactions to be separated by membranes within the cytoplasm (isolation results in increased efficency)

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37
Q

Nucleus

A

Nucleus: contains DNA, genetic material. The DNA is organized in structures called chromosomes, associated with proteins. Controls cell activity, including mitosis, replication of DNA

  • generally in the centre of the cell; most cells possess a singular nucleus
    exeption; RBC don’t have any
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38
Q

Nucleolus

A

Nucleolus: found in nucleus. Ribosome factory (production of ribosomal RNA and assembly of ribosomal subunits)

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39
Q

Endoplasmic Retiuclum

A

Endoplasmic Reticulum: a network of membrane tubules.

Rough ER: dotted with RIBOSOMES, in which proteins are synthesized

Smooth ER: produces lipids, membrane components, production of sex hormones such as testosterone and oestrogen, detoxification of drugsin the liver, storage of calcium ions in muscle cells, liver release of glucose

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40
Q

Golgi apparatus

A

Golgi Apparatus: modifies + packages + ships proteins/matierals throughout the cell

  • looks like a wifi symbol
  • consists of cisternae (flattened sacs stacked on top of each other)
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41
Q

Lyosome

A

Lysosome: Contains digestive enzymes which help to break down macromolecules, removes waste and protects cell from invaders

42
Q

Chloroplast

A

Chloroplasts (PLANTS): captures sunlight +uses energy to convert water +CO2= sugar + O2 (PHOTOSYNTHESIS) (with chloroplhyll)

  • contains double membrane, similar size to bacterial cell, has own circular DNA and 70s ribosomes
  • contains thylakoids (in granum structure) and stroma which absorve light
  • can reproduce indepently of cell
43
Q

Mitochondria

A

Mitochondria: produces energy (ATP); site of cellular respiration

  • similar size to bacteria; has own circular DNA and functions, double membrane, inner cristae foldings and matrix cluid
  • contain 70 s ribosomes
  • muscle cells have a lot of them due to high energy requirement
44
Q

Centrosome

A

Centrosomes: where CENTRIOLES (microtubules that move chromosomes during cell division) form

45
Q

Large vacuole

A

Large Vacuole(PLANTS): contains water, occupies large space. Animal cell may have a small vacuole sometimes.

46
Q

Cytoskeleton

A

Cytoskeleton: (microtubules) filaments that reinforce cell shape

47
Q

Cell wall (plants)

A 
Cell Wall(PLANTS): protects +keeps cell structures
- composed of cellulose
48
Q

Amyloplasts

A

Amyloplast(PLANTS): starch grain

49
Q

Cell membrane eukaryote

A

Cell membrane: decides what comes in and out of the cell, structural, protection

50
Q

cytoplasm

A

Cytoplasm: site where chemical reactions take place

- fluid portion called cytosol

51
Q

Ribosome (eukaryote)

A
  • 80-90 s size
  • composed of RNA and a protein
  • protein synthesis
  • 2 subunits
52
Q

eukaryotic DNA

A
  • comes in chromosomes; carry all information needed for cell to exist
  • when cell isn’t dividing, chromosomes not visible as visible structures (chromatin form)
  • contained in the nucleus as a nucleosome (DNA wrapped around 8 histone proteins)
53
Q

compare prokayotic and eukaryotic cells

A

PROKARYOTIC;

  • DNA in ring form without protein
  • DNA free in cytoplasm
  • No mitochondria
  • 70 s ribosomes
  • no internal compartmentalization of organelles
  • size less than 10 um
  • divide using binary fission
  • peptidoglycan in cell wall

EUKARYOTIC;

  • DNA with proteins as chromosomes (assosiated with histones)
  • DNA enclosed with a nucleor envelope
  • Mitochondria present
  • 80 s ribosomes
  • compartmentalized organnless (membrane bound)
  • size more than 10 um
  • divide using mitosis and meiosis
  • plant cells have cellulose as cell wall

SIMILARITES:

  • both carry out all functions of life
  • DNA present in both
  • both have a plasma membrane
54
Q

Compare PLANT and ANIMAL Cells

A

PLANT:

  • contain cell wall
  • chloroplasts present
  • LARGE vacuoles
  • carbohydrates stored as starch
  • don’t contain centrioles
  • cell has fixed, angular shape

ANIMAL:

  • no cell wall (only plasma membrane)
  • no chlorplastas
  • only small vacuoles (if even present)
  • carbohydrates stored as glycogen
  • contain centrioles within a centrosome area
  • no cell wall; flexible and rounded shape

SIMILARITIES:

  • membrane bound organnless
  • both have mitochondria, and cellular respiration
55
Q

ECM

A

extra cellular matrix; in animal cells and composed of collagen fibres + sugars + glycoproteins

  • strengthen plasma membrane and allow attachments
  • involved in stem cell differentiation
56
Q

Davidson danielli Falsification

A

Davidson Danielli: chemical analysis, presence of protein.
Theory: phospholipid bilayer sandwiched between 2 layers of protein

falsified;

  • not all membranes are identifical
  • membranes with different functiosn have different combositions and structures
  • a protein layer would be largerly non polar and therefore not interface with water
57
Q

Fluid Mosaic Model

A

Fluid Mosaic Model: singer nicolson and daniel braxton, accurate on of the phospholipid bilayer with lil bits of protein

58
Q

membrane protein functions

A
  • Hormone binding sites
  • Enzymatic action
  • Cell adhesion
  • Cell to cell communication
  • Active and passive transport
59
Q

membrane protein types

A
  • Integral proteins
  • peripheral proteins
  • Glycoproteins
60
Q

Membrane structures

A
  • proteins
  • cholosterol
  • phospholipids
61
Q

Integral/Intrinsic/Transmembrane

A

proteins span whole width.
Carrier/channel of molecules, transport substances (ions, sugar, amino acids, etc.)
Receptors for hormones and neurotransmitters and enzymes

62
Q

Peripheral (extrinsic)

A

inner/outer surface of membrane.
Receptor for hormones/neurotransmitters,
cell recognition, are glycoproteins

63
Q

Glycoproteins:

A

Glycoproteins: attached to carbohydrate chains

64
Q

Phospholipids

A
  • polar (hydrophyllic) head and non polar (hydrophobic tail)
  • composed of glycerol (fatty acids) carbons and a polar phosphate group
  • membranes have two distinct area of polarity and water solubility
65
Q

Phospholipid bilayer

A
  • backbone structure consists of two layers of phospholipids that create a bilayer due to the polar and non polar structures
  • are fluid and flexible; allows for animal cells to have variable shape and allows for exocytosis
  • overal structure of membrane is the tendency of water to form hydrogen bonds
66
Q

Cholesterol

A
  • maintains fluidity and homeostatis of membrane

- allows for membrane to function at fluctuating temperatures

67
Q

types of cellular transport

A
  • passive transport

- active transport

68
Q

Osmosis

A

Osmosis: movement of water molecules from a high concentration to a low concentration through a semipermeable membrane

69
Q

Simple Diffusion

A

Diffusion: net movement of particles from a high to low concentration (down a concentration gradient)

70
Q

Facilitated diffusion

A

Facilitated diffusion: occurs through channels, it’s passive but controlled

71
Q

ACTIVE TRANSPORT

A

Carrier proteins transport certain molecules against the concentration gradient

Requires ATP to do so

Molecule: ions, glucose, amino acids

Example: small intestine (uptake of glucose and amino acids), absorption of mineral ions by plant roots, excretion of urea by kidneys, exchange of sodium and potassium ions in neuron and muscle cells

CELLS THAT UNDERTAKE LARGE-SCALE ACTIVE TRANSPORT HAVE MANY MITOCHONDRIA, AS A LOT OF ATP IS NEEDED

72
Q

Size and charge

A

size and polarity of a molecule determines the ease by which it can cross a membrane;

small and non polar molecules easily cross membranes;
(oxygen, carbon dioxide, nitrogen)

large and polar substances struggle
(glucose and sucrose and ions)

73
Q

Sodium-Potassium Pump

A
  1. Specific protein binds to three intracellular sodium ions
  2. The binding of sodium ions causes phosphorylation by ATP. ATP has three attached phosphates; when it carries out phosphorylation, one phosphate is lost, resulting in a two-phosphate compound called ADP.
  3. The phosphorylation cuases the protein to change its shape; thus expelling sodium ions to the exterior
  4. the extracellular potassium ions bind to different regions of the protein; causing the relase of phosphate groups
  5. loss of phosphate group restores proteins original shape; CAUSES release of pottasium ions into the intracellular space
74
Q

another example of active transport

A
  • liver cells use active transport to accumulate glucose molecules from blood plasma even though the liver has a higher glucose concentration
75
Q

endocytosis

A

Endocytosis (pinocytosis/phagocytosis/phagolysosome) : into cell; absorption of material using a vesicle, formation of vesicle from plasma membrane allow material to be taken in.

Vesicles are made by pinching off a piece of a membrane and can be used to transport materials around the cell.
Invagination of the membrane forms a flask=like depression which envelopes material, and is then sealed off to form a vesicle.

Types:

  1. PHAGOCYTOSIS: process by which solid substances (e.g.g food particles) are ingested *usually to be transported by the lysosome for breakdown)
  2. PINOCYTOSIS: process by which liquids/solutions (dissolved substances) are ingested by the cell (allows quick entry for large amounts of substance)
76
Q

exocytosis

A

Exocytosis: out of cell process by which large substances exit the cell without travelling across a plasma membrane,

vesicles fuse with plasma membrane,
expelling their contents into the extracellular environment,
vesicles are formed by the golgi apparatus

77
Q

BULK TRANSPORT

A

BULK TRANSPORT: when large substances need to be moved across the cell membrane

78
Q

exocytosis process

A
  1. proteins produced by the ribosomes of the rough ER enter lumen of ER
  2. Protein exists the ER and enters the cis side of the golgi apparatus; a vesicle is involved
  3. as the protein moves through the golgi apparatus, it is modified and exists on the trans side inside a vesicle
  4. the vesicle with the modified protein inside moves to and fuses with the plasma membrane; secreting the contents
79
Q

examples of exocytosis

A
  • pancreas cells produce insulin to secret into the bloodstream to regulate sugar levels
  • neurotransmitters are released at synapses in the nervous system
80
Q

exeptions to cell theory

A
  • multinucleuted cells of striated muscle cells, fungal hyphae
  • large cells with contnioues cytoplasm
  • virsues
  • problem with explaning ‘the first cells’
81
Q

ENDOSYMBIOTIC THEORY

A

Explains the existence of several organelles of eukaryotes, the theory states that the organelles originated as symbioses between separate single-celled organisms
E.g. chloroplasts and mitochondria

82
Q

MILLER AND UREY:

A

Scientists which conducted experiments (electrical impulses + a liquid bath with a bunch of chemicals) to recreate the conditions of pre-biotic earth, a week later they found 13/20 naturally occurring amino acids, which are the foundations for proteins, therefore the foundations of life

83
Q

ENDOSYMBIOTIC THEORY EVIDENCE:

A

Mitochondria have their own membrane, DNA (naked and circular), and can reproduce

Ribosome size similar to that of prokaryotes

Mitochondria and chloroplasts can produce their own energy

Evolutionary drive (oxygen toxic; look for protection, inability to ingest large amounts of nutrients)

Timeline of creation (prokaryotes, then oxygen and then eukaryotes)

Chloroplasts have a similar size to bacteria

Synthesis of DNA, RNA, RIBOSOMES, CHLOROPHYLL and PROTEINS similar to that of bacteria

84
Q

MITOSIS

A
  • Happens everywhere
  • Cell division of somatic cells
  • Produces 2 diploid identical daughter cells
  • Asexual reproduction
  • 1 cycle of chromosome duplication and splitting
85
Q

Meiosis:

A
  • Happens in the sexual organs
  • Cell division of sex cells
  • 4 haploid un-identical daughter cells produced
  • Sexual reproduction
  • 2 cycles of chromosome duplication and splitting
86
Q

CELL CYCLE:

A
  • behaviour of cells adn they grow and divide

- integrates a growth phase with a division phase

87
Q

Interphase

A

G1 (growth 1): cell grows, protein synthesis and respiration

S (synthesis): DNA Synthesis (Chromosomes replicate)

G2: Second growth, mitochondria and other organelles distributed and centrosomes divide

C: control checkpoint, repairs and checks damage of DNA before proceeding to mitosis

MITOSIS: process of nuclear division

88
Q

Prophase

A

Prophase:
chromatin condenses and spindle fibers form
nuclear envelope disintegrates and nucleoli dissapear
centrosomes move to opposite poles of the cell

89
Q

Metaphase

A

Metaphase:

spindle fibers attach to the centromeres of sister chromatids and chromosomes align in the equatorial plane

90
Q

Anaphase

A

Anaphase: when two sister chromatids of each chromosome split

  • centromeres cleave and chromatids separate, being pulled to opposite sides of the cell
  • chromatids become chromosomes
91
Q

Telophase

A

Telophase: new nuclear envelope forms and chromosomes uncoil and become invisible to microscope, cytokinesis begins

92
Q

Cytokenesis

A

splitting of cell into two daughter cells

93
Q

CYCLINS

A

are a family of proteins that control the progression of cells through the cell cycle

94
Q

CYCLINS process

A
  1. Cells cannot progress to the next stage of the cell unless a specific cycle reades its threshold
  2. Cyclins bind to enzymes called cyclin-dependent kinases (family related enzymes)
  3. These kinases then become active and attach phosphate groups to other proteins in the cell
  4. The attachment of phosphate triggers the other proteins to become active and carry out tasks (specific to one of the phases of the cell cycle)
95
Q

MITOTIC INDEX

A

ratio between the # of cells in mitosis in a tissue and the total # of observed cells

Mitotic index= number of cells in mitosis/total number of cells

96
Q

Tumour formation:

A

MUTAGENS: carcinogens (cancer causing) chemicals, high energy radiation (e.g. X-RAYS)

ONCOGENES: genes that have mutated that can cause cancer

METASTASIS: movement of cells form a primary tumour to set up a secondary tumour (spreading)

97
Q

FEATURES OF A CANCER CELL (TUMOUR):

A

cancer cells do not differentiate into a specialist cell type

a cancer cell is parasitic taking nutrients from
surrounding cells by forming large numbers of blood vessels to supply it

a cancer cell undergoes uncontrolled division

98
Q

RISK FACTORS: anything that increases a chance of developing a disease

A

Smoking is a major risk
Risk factors are correlational with a disease but not necessarily causal
E.g. international travel; rise factor for malaria, however the parasite in the mosquito’s is the cause

99
Q

LUNG CANCER:

A

Biggest cause of cancer-related deaths, 90% of cases caused by smoking
Most cases are due to uncontrolled growth of epithelial cells lining the airway, cancers arising from these cells are called carcinomas
Symptoms: shortness of breath, coughing, weight loss

100
Q

cancer lung cancer studies

A

STUDIES:
Richard Doll and Austin Bradford: investigated 1700 men and women in london
British male doctors: lifelong smokers died, on average, 10 years earlier than non-smokers

IB BIOLOGY 2017 EXAM (11 decks)

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