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OAT QUESTION > Cell and Molecular Biology > Flashcards

Cell and Molecular Biology Flashcards

1
Q

The cell theory

A
  • All living things are composed of cells. -The cell is the basic functional unit of life.
  • The chemical reactions of life take place inside the cell.. -Cells arise only from pre-existing cells.
  • Cells carry genetic information in the form of DNA. This genetic material is passed from parent cell to daughter cells.
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2
Q

The six type of kingdom

A

-Bacteria -Archaea -Protista -Fungi -Plantae Animalia

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3
Q

Cell membrane

A

-phospholipid bilayer. -selective permeability -The phospholipid molecules are arranged such that the long, non-polar, hydrophobic, fatty chains of carbon and hydrogen face each other. -it is permeable to small non polar hydrophobic molecules such a oxygen and small polar and small charged ions. However charged ions and larger charged molecules cross the membrane with the assistance of carrier proteins.

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4
Q

Nucleus

A

the nucleus contains DNA wound around structural proteins called histones . It also contains a dense structure called the nucleolus where ribosomal RNA( rRNA) synthesis occurs. Prokaryotes do not have nuclei and therefore do not possess histones to organize their DNA into linear chromosomproduction es. Instead, prokaryotic DNA is organized into small circular chromosomes located in a region of the cell termed the nucleoid.

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5
Q

Ribosome

A

-production of protein. - rRNA are synthesized in the nucleolus of eukaryotes, they function in either the cytoplasm or rough ER. -In prokaryotes rRNA synthesis and ribosome function occurs in the cytoplasm.

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6
Q

Endoplasmic reticulum (ER)

A

membrane enclosed spaced involved in the transport of materials throughout the cell. Rough Er-contains ribosome -synthesis of proteins. Smooth Er- does not contain ribosomes- involved with metabolism and the production of lipids.

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7
Q

Golgi apparatus

A

primary site for cellular trafficking . It receives vesicles and their contents from the smooth ER and then modifies them(glycosylation), repackages them into vesicles and distributes them to the cell surface for exocytosis.

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8
Q

Mitochondria

A

are the sites of aerobic respiration within the cell. they convert sugars, fats, and other sources of fuel into usable energy(ATP). It is composed of an outer and inner membrane. The inner membrane folds into cristae. It has its own genome which allows it to divide independently of the nucleus via binary fission.

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9
Q

Cytoplasm

A

site of metabolic activities

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10
Q

Vacuoles/ Vesicles

A

membrane bound sacs involved in the transport and storage of materials that are ingested, secreted , processed or digested by the cell. Vacuoles are larger than vesicles and are found in plants.

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11
Q

Centrioles

A

are composed of microtubules and are involved in spindle organization during cell division.They are not bound by a membrane. Plant cells do not contain centrioles.

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12
Q

Lysosomes

A

are membrane- bound vesicles that contain hydrolytic enzymes involved in intracellular digestion. lysosomes break down material ingested by the cell.

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13
Q

Cytoskeleton

A

The cytoskeleton supports the cell, maintains its shape, and aids in cell motility. It is composed of microtubules, microfilaments and intermediate filaments. Microtubules are hollow rods made up of polymerized tubulin. -Microtubules provide the framework for organelle movement within the cell. centrioles have microtubules which help in cell division. Cilia and flagella are specialized microtubules

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14
Q

Cytokinesis

A

-Contain Actin and Myosin -Cytokinesis is different in plants, as no cleavage furrow forms, but a cell plate is formed A new cell wall forms between the two cell plate membranes.

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15
Q

Microfilaments

A

move materials across the plasma membrane. Actin.

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16
Q

Intermediate Filament

A

serve as the structural backbone of the cell and anchor organelles to their respective places in the cell.

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17
Q

Simple Diffusion

A

is the net movement of particles down their concentration gradients- from a region of higher concentration to a region of lower concentration. This is a passive process.

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18
Q

Osmosis

A

is the simple diffusion of water from a region of lower solute concentration to a region of higher solute concentration.

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19
Q

Hypertonic

A
  • if the extracellular fluid has a higher osmolarity than the cell’s cytoplasm, it’s said to be hypertonic—hyper means greater than—to the cell, and water will move out of the cell to the region of higher solute concentration.
  • When the cytoplasm of a cell has a lower solute concentration than the extracellular medium, water will flow out of the cell into the surrounding medium.
  • This is plasmolysis, it will cause the cell to shrivel.
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20
Q

Hypotonic

A

If the extracellular environment is less concentrated than the cytoplasm of the cell. water will flow into the cell,causing it to swell and lyse(burst).

  • If the extracellular fluid has lower osmolarity than the fluid inside the cell, it’s said to be hypotonic—hypo means less than—to the cell, and the net flow of water will be into the cell.
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21
Q

Isotonic

A

If the extracellular enviroment has the same concentration of solutes as the cell cytoplasm. the water will move back and forth in equal amounts across the cell membrane.

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22
Q

Facilitated Diffusion

A

is the net movement of dissolved particles down their concentration gradient through special channels or carrier proteins in the cell membrane .

This process does not require energy.(passive transport)

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23
Q

Active Transport

A

is the net movement of dissolved particles against their concentration gradients with the help of transport proteins. It requires energy.

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24
Q
  1. Symporters
  2. Antiporters
  3. Pumps
A
  1. move two or more ions in the same directions across the membrane.
  2. exchange one or more ions (or molecules) for another ion or molecule across the membrane.
  3. Energy-dependent carriers require (require ATP)
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25
Q

Endocytosis

A

is a process in which the cell membrane invaginates, forming a vesicle that contains extracellular medium. Allowing the cell to bring in large volumes of extracellular material inside the cell.

the materials never pass thru the cell membrane.

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26
Q
  1. Pinocytosis
  2. Phagocytosis
A
  1. is the the ingestion of fluids or small particles .
  2. is the engulfing of large particles
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27
Q

Exocytosis

A

a vesicle within the cell fuses with the cell membrane and releases a large volume of contentsto the outside.

Help with cell growth and intercellular signaling( neurotransmitters).

the materials never pass thru the cell membrane.

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28
Q

Cell division

A

is the process by which a cell doubles its organelles and cytoplasm, replicates its DNA and then divides in two.

For unicellular organisms, cell division is a means of reproduction whereas for multicellular organisms it is a method of growth, development, and replacement of worn-out cells.

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29
Q

Central dogma

A

DNA—RNA—PROTEINS

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30
Q

DNA STRUCTURE

A

the basic unit of DNA is the nucleotide.

A nucleotide consist a deoxyribose( sugar) bonded to both a phosphate group and nitrogenous base.

The two types of bases are PURINES AND PYRIMIDINES.

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31
Q

Purines and

Pyrimidines

A

Purines-Adenine & Guanine

Pyrimidines- Cytosine and thymine. RNA contain Uracil.

Purines are larger in structure than pyrimidines because they posses a two-ring nitrogenous base.

pyrimidines have a one ring nitrogenous base.

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32
Q

DNA

A

DNA is double-stranded helices of complementary strands with the sugar-phosphate chains on the outside of the helix and the nitrogenous bases on the inside.

They are held together by hydrogen bonds

T =A (2 bonds)

G=C (forms 3 hydrogen bonds)

Antiparallel

33
Q

DNA replication

A
  1. The double stranded DNA is unwinded by DNA helicase to form two single strands.
  2. The opening in the DNA molecule created by the DNA helicase is known as the replication fork. As the DNA is replicated, the fork continues to travel up the DNA molecule, which cause a build up of torsional strain upstream of the replication fork.
  3. Topoisomerase removes this strain by cutting, twisting and then rejoining the strand
  4. Semiconservative- has a daughter strands of DNA formed the parent strand. I new and 1 old
34
Q

DNA polymerase

A

DNA polymerase reads the parent DNA strand and creates a complementary, antiparallel daughter strand.

DNA polymerase always reads the parents strand in the

3’→5’ direction, creating a new daughter strand in the 5’→3’ direction.

DNA polymerase can only add nucleotides to 3’ ends of DNA strands.

35
Q

Leading strand

A

The leading strand has its 3’end facing towards the replication fork, thereby allowing DNA polymerase/ DNA synthesis and the replication fork to travel the same direction continually.

36
Q

DNA Polymerase

A

DNA polymerase proteins must reattach to the parent strand near the continually moving replication fork. The short fragments of synthesized DNA is called OKazaki fragments.

As the lagging strand is formed the fragments are held together by DNA ligase.

37
Q

Transcription

A

is the process in which genetic information is passed from DNA to RNA. The RNA, specifically messenger RNA, is transcribed in the 5’→3’ direction and is complementary and antiparallel to the DNA template strand.

The coding strand of DNA is identical to the mRNA strand, with the exception that all thymines bases are exchanged for uracil.

38
Q

Translation

A

is the process in which genetic information is passed from mRNA to protein. The ribosome translate the mRNA in the 5’→3’ direction and the protein is sythesized from amino terminus(N-terminus) to the carboxyl terminus (C- terminus)

39
Q

RNA structure

A

very similar to DNA except.

  • The sugar constituent is ribose
  • Uracil is used in place of thymine
  • Most RNA is single- stranded.

RNA can be found in both the nucleus and cytoplasm of the cell.

40
Q

Messenger RNA

A

mRNA carries the compliment of the DNA sequence. transport the information from the nucleus to the ribosome for protein synthesis.

Eukaryotic mRNA is monocistronic, meaning that one mRNA strand codes for one polypeptide

41
Q

Transfer RNA

A

is a small RNA molecule found in the cytoplasm. It assist in the translation of mRNA into sequence of amino acids. tRNA recognizes the mRNA codon and its coresponding amino acid

42
Q

Ribosomal RNA(rRNA)

A

Is synthesized in the nucleolus of eukaryotes and in the cytoplasm of prokaryotes.

It is the most abundant in the cell.

43
Q

Transcription

A

is the process through which information coded in the sequence of DNA is used to direct the synthesis of a strand of RNA.

After the post- transcriptional modification , the RNA leaves the nucleus through nuclear pores.

44
Q

Transcription step

A
  1. RNA polymerase binds to the DNA template strand at a promoter region( TATA box).
  2. RNA polymerase transcribes a new RNA strand. It read the DNA in 3’→5’ direction and creates a new daughter strand of RNA in the 5’→3’ direction.

A—U

45
Q

Post-transcriptional processing

A
  • Introns- are extra sequences that are removed out by the spliceosome.
  • Exons- are the nucleotides necessary to make the protein and are kept during the post- transcriptional processing.
  • 5’guanine cap and aseries of adenines known as a poly-A tail. They provide protection from RNA- degrading enzymes within the cytosol.

After these things RNA molecule, it is termed mRNA and can leave the nucleus.

46
Q

Ligases

A

a ligase is an enzyme that can catalyze the joining of two large molecules by forming a new chemical bond.

47
Q

Isomerases

A

Isomerases are a general class of enzymes that convert a molecule from one isomer to another. Isomerases facilitate intramolecular rearrangements in which bonds are broken and formed.

48
Q

Lyases

A

catalyze the cleavage of a single molecule into two products w/o water as a substrate and do not require oxidoreductases.

49
Q

Hydrolases

A

catalyze the breaking of a compound into two molecules using the addition of water.

ex.phosphatase, peptidases, nucleases, and lipases

50
Q

Oxidoreductases

A

catalyze oxidation- reduction reactions, that is, the transfer of electrons between biological molecules. They are cofactors.

ex. NAD+, dehydrogenase or reductase

51
Q
  • Transferases
  • Kinases
A
  • catalyze the movement of a functional group from one molecule to another .
  • catalyze the transfer of a phosphate group, generally from ATP to another molecule.
52
Q

Cellular respiration

A

describes the biochemical conversion of chemical energy stored in molecular bonds into usable energy(ATP), a catabolic process.

Aerobic respiration: in the presence of oxygen

Anaerobic respiration- occurs in the absence of oxygen

53
Q

External and Internal respiration

A

External respiration refers to the inhaling and exhaling of air into and out of the lungs as well.

Internal respiration refers to exchange of gas between individual cells and the extracellular fluid.

54
Q

Glycolysis

A

The degradation of glucose by oxidation begins with glycolysis and then splits into two separate pathways, Aerobic and anaerobic .

AEROBIC

  • Decarboxylation of pyruvate
  • Krebs cycle
  • Electron transport chain.

ANAEROBIC

  • Fermentation
55
Q

energy investment stage

A

2 ATPs are used to add two phosphate groups to glucose.

producing fructose 1,6-biphosphate . These action are completed by kinases.

56
Q

Cleavage

A

splits fructose 1,6-biphosphate into glyceraldehyde 3-phosphate and dihydroxyacetone phosphate( DHAP).

DHAP is then isomerized to form a second PGAL.

57
Q

Glycolysis net reaction

A

under anaerobic conditions (absense of oxygen), pyruvate is reduced during the process of fermentation. NAD+ must be regenerated for glycolysis is continue in the absnce of 02. This is accomplished by reducing pyruvate into ethanol or lactic acid via fermentation.

Under aerobic conditions ( in the presence of oxygen ), pyruvate is further oxidized during cellular respiration in the mitochondria.

58
Q

Alcohol fermentation

A

occurs in yeast and some bacteria. The pyruvate produced in glycolysis is converted to ethanol. In this way, NAD+ is regenerated and glycolysis can continue.

Fermentation does not produce any ATP itself; glucose metabolized in the anaerobic pathway only produces the two ATP through glycosis.

59
Q

Aerobic respiration

and anaerobic respiration

A

aerobic respiration can yield 36-38 ATP.

Anaerobic respiration yield 2 ATP.

Aerobic respiration happens in the mitochondria for eukaryotes and the cytoplasm for prokaryotes.

Prokaryotes: citric acid cycle occurs in the cytosol and the ETC in the bacterial membrane.

60
Q

Glycolysis

A

literally means “sugar breaking” and is a series of reactions that lead to the oxidative breakdown of glucose into two molecules of pyruvate, the production of ATP, and the reduction of NAD+ into NADH.

  • Glucose is reduced and NAD+ is oxidized.
  • Glycolysis occurs in the cytoplasm and can be completed by both prokaryotes and eukaryotes.
61
Q

Pyruvate decarboxylation

Citric Acid Cycle

A

pyruvate is transported to the mitochondria where it is decarboxylated (loses a CO2) and the acetyl group that remains is transferred to coenyme A to form acetl -CoA.

NAD+ IS REDUCED to NADH.

62
Q

Citric Acid cycle( Kreb Cycle)

A

1 molecule of glucose= 2 pyruvate

63
Q

The net equation of the citric acid cycle

A
64
Q

The electron transport chain (ETC)

A

Takes place on the inside of the inner mitochondrial membrane. During Oxidative phosphorylation, ATP is produce due to the tansfer of NADH AND FADH2.

The ETC uses cytochrome electron carriers. It uses a redocx reaction.

The coupling of the oxidation of NADH and FADH2 with the phosphorylation of ADP is called the oxidative phosphorylation.

65
Q

Photosynthesis

A

All green plants use it to convert carbon dioxide and water into glucose and oxygen . Glucose can be stored as starch or used as energy source. Plants have chloroplast but photosynthetic bacteria lack chloroplast but can perform the similar functions.

Photosynthesis is a reduction of CO2 by the release of oxygen and formation of water.

Photosynthesis can be divided into light and dark reactions.

66
Q

Light reactions

A

which require sunlight.

it splits H20 and produce both ATP and NADPH.

chlorophyII absorbs light.

it has two pathways the cyclic flow or noncyclic flow

  • The net result of noncyclic electron flow is the production of NADPH and ATP and the break down of water.
  • Happens in the thylakoid
67
Q

Dark reaction( carbon fixation).

Calvin cycle

A

coupled with the light reactions, do not requre sunlight.

it is a reduction synthesis, form sugar from CO2 and the energy produced in the light reaction.

The dark reaction use the ATP and NADPH produced by the light reaction to reduce CO2 to carbohydrates

Carbon fixation- the formation of glucose(organic compound) from CO2.

Happens in the stroma

68
Q

Calvin cycle

A
69
Q

post translational modification

A

phosphorylation: Addition of a phosphate group.

Carboxylation: Addition of carboxylic acid groups.

Glycosylation: Addition of oligosaccharides( sugars) completed in the golgi body.

Prenylation: Addition of liquid groupss, allowing for incorporation of the protein into membranes.

70
Q

Prokaryotes

A

In eukaryotes, transcription occurs in the nucleus

prokaryotes: transcription happens in the cytoplasm.no posttranscriptional modification.

71
Q

Proteins

A

formed by the culmination of transcription and translation , proteins are the functional units of life .

enzymes are proteins.

72
Q

The primary protein structure

A

of a protein is the sequence of amino acids, determined by its mRNA strand. It list amino acids from the N-terminus to C-terminus. Peptide bonds link them together.

73
Q

Secondary protein structure

A

it is the 3D structure of neighboring amino acids, which is determined by the primary structure of the protein.

The alpha and beta sheet. The secondary structure stability relies on hydrogen bond formation between amino acid side chains

74
Q

Tertiary protein structure

A

of a protein refers to the folding of a polypeptide forming the 3D structure. the folding is called chaperones. Tertiary structure relies on the hydrophobic and hydrophillic interactions of amino acid side groups, as well as disulfide bonds.

75
Q

Quaternary structure

A

Of a protein describes the combining of polypeptides to form a complete protein complex.not all protein have quaternary structure. Hemoglobin is a tetramer formed by four separate polypeptides(subunit)

76
Q

Enzymes

A

Enzymes do not akter the equilibrium constant.

Enzymes are NOT consumed in the reaction.

Enzymes lower the activation energy of a rxn.

Enzymes are pH and temperature sensitive.

77
Q

Lock and Key Theory

A
78
Q
A

OAT QUESTION (5 decks)

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