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Biology 95F > Cell Biology > Flashcards

Cell Biology Flashcards

1
Q

Define: Prokaryotes

A

Any of the group of organisms primarily characterized by the lack of true nucleus and other membrane-bound cell compartments: such as mitochondria and chloroplasts, and by the possession of a single loop of stable chromosomal DNA in the nucleiod region and cytoplasmic structures, such as plasma membrane, vacuoles, primitive cytoskeleton, and ribosomes.

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2
Q

Define: Eukaryotes

A

cells are organized into compartmentalized structures called organelles, the nucleus in particular. The presence of a distinct nucleus encased within membranes differentiates the eukaryotes from the prokaryotes. The eukaryotes are also known for having cytoplasmic organelles apart from nucleus, such as mitochondria, chloroplasts and Golgi bodies

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3
Q

Define: TEM

A

TEM –> transmission electron microscopy
Those forms of electron microscopy in which electrons are transmitted through the object to be imaged, suffering energy loss by diffraction and to a small extent by absorption.

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4
Q

Define: SEM

A

Scanning electron microscope (SEM)

a type of electron microscope capable of producing high resolution images of a sample surface.

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5
Q

Define: Plasma membrane

A

The cell’s outer membrane made up of a two layers of phospholipids with embedded proteins, and separates the contents of the cell from its outside environment, as well as regulates what enters and exits the cell

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6
Q

Define: Organelles

A

Plural form of organelle, i.e. a membrane-bound compartment or structure in a cell that performs a special function

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7
Q

Define: Cell wall

A

A membrane of the cell that forms external to the cell membrane whose main role is to give cells rigidity, strength and protection against mechanical stress

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8
Q

Define: Cell envelope

A

The cell envelope comprises the inner cell membrane and the cell wall of a bacterium. In gram-negative bacteria an outer membrane is also included. This envelope is not present in the Mollicutes where the cell wall is absent.

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9
Q

Define: Cytoplasm

A

The contents of a cell surrounded by the cell membrane, except for the nucleus in the eukaryotic cell

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10
Q

Define: Nucleus

A

The large, membrane-bounded organelle that contains the genetic material, in the form of multiple linear DNA molecules organized into structures called chromosomes

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11
Q

Define: Nuclear envelope

A

The two layered membrane that encases the nucleus of a eukaryotic cell, which separates the nucleus from other cell organelles

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12
Q

Define: Ribosome

A

A minute, sphere-shaped particle composed of protein and ribonucleic acid (RNA) that serves as the site of protein synthesis

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13
Q

Define: DNA

A

Deoxyribonucleic acid

A nucleic acid that generally is double-stranded and helical, and a crucial biomolecule for containing the genetic information for cell growth, division, and function

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14
Q

Define: RNA

A

Ribonucleic acid

A nucleic acid that is frequently single-stranded and folded onto itself, and composed of repeating nucleotide units of ribose sugar, phosphate group, and nitrogenous base

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15
Q

Define: Amino acids

A

The building block of protein in which each is coded for by a codon and linked together through peptide bonds.

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16
Q

Define: Endoplasmic reticulum

A

A membrane-bound organelle that occurs as labyrinthine, interconnected flattened sacs or tubules connected to the nuclear membrane, running through the cytoplasm, and may well extend into the cell membrane

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17
Q

Define: Golgi apparatus

A

An organelle that is comprised of membrane-bound stacks and is involved in glycosylation, packaging of molecules for secretion, transporting of lipids within the cell, and giving rise to lysosomes

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18
Q

Define: Lysosomes

A

Organelle containing a large range of digestive enzymes used primarily for digestion and removal of excess or worn-out organelles, food particles, and engulfed viruses or bacteria

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19
Q

Define: Peroxisomes

A

Peroxisome, membrane-bound organelle occurring in the cytoplasm of eukaryotic cells. Peroxisomes play a key role in the oxidation of specific biomolecules. … Specialized types of peroxisomes have been identified in plants, among them the glyoxysome, which functions in the conversion of fatty acids to carbohydrates.

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20
Q

Define: Mitochondria

A

A spherical or rod-shaped organelle with its own genome, and is responsible for the generation of most of the cell’s supply of adenosine triphosphate through the process of cellular respiration

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21
Q

Define: Chloroplasts

A

Chlorophyll-containing plastid found within the cells of plants and other photosynthetic eukaryotes

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22
Q

Define: Vacuoles

A

A membrane-bound vesicle found in the cytoplasm of a cell whose function includes intracellular secretion, excretion, storage, and digestion

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23
Q

Define: Cytoskeleton

A

The lattice or internal framework of a cell composed of protein filaments and microtubules in the cytoplasm, and has a role in controlling cell shape, maintaining intracellular organization, and in cell movement

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24
Q

Define: Centrosomes

A

The organelle located near the nucleus in the cytoplasm that divides and migrates to opposite poles of the cell during mitosis, and is involved in the formation of mitotic spindle, assembly of microtubules, and regulation of cell cycle progression; the region pertaining to the organelle.

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25
Define: Fluid Mosaic Model
The fluid mosaic model explains various observations regarding the structure of functional cell membranes. According to this biological model, there is a lipid bilayer in which protein molecules are embedded. The lipid bilayer gives fluidity and elasticity to the membrane
26
Define: Membrane proteins
A type of protein that is attached to, or associated with, a biological membrane (i.e. of a cell or of an organelle) Proteins are one of the most essential biomolecules. They serve as structural material, as enzymes, as transporters, as antibodies, or as gene expression regulators. They are made up of polymers comprised of amino acids.
27
Define: Plasma membrane
The cell’s outer membrane made up of a two layers of phospholipids with embedded proteins, and separates the contents of the cell from its outside environment, as well as regulates what enters and exits the cell
28
Define: Cytoplasmic membrane
The plasma membrane, also called the cytoplasmic membrane, is the most dynamic structure of a procaryotic cell. Its main function is a s a selective permeability barrier that regulates the passage of substances into and out of the cell.
29
Define: Phospholipids
Phospholipids are a subgroup of lipids. Other major types of lipids are fatty acids, sphingolipids, sterol lipids, and prenol lipids. Lipids are organic compounds that are readily soluble in nonpolar solvent (e.g. ether) but not in polar solvent (e.g. water).
30
Define: Osmotic pressure
A hydrostatic pressure caused by a difference in the amounts of solutes between solutions that are separated by a semi-permeable membrane.
31
Define: Types of Carbohydrate chains
Carbohydrate chains come in different lengths, and biologically important carbohydrates belong to three categories: monosaccharides, disaccharides, and polysaccharides.
32
Define: Passive transport
A kind of transport by which ions or molecules move along a concentration gradient, which means movement from an area of higher concentration to an area of lower concentration The four major types of passive transport are (1) simple diffusion, (2) facilitated diffusion, (3) filtration, and (4) osmosis.
33
Define: Active transport
A kind of transport wherein ions or molecules move against a concentration gradient, which means movement in the direction opposite that of diffusion – or – movement from an area of lower concentration to an area of higher concentration. Hence, this process will require expenditure of energy, and the assistance of a type of protein called a carrier protein
34
Define: Osmosis
Diffusion of a solvent (usually water molecules) through a semipermeable membrane from an area of low solute concentration to an area of high solute concentration.
35
Define: Isotonic
Having equal tension or tonicity
36
Define: Selectively-permeable membrane
A membrane that is selectively permeable, i.e. being permeable to only certain molecules and not to all molecules.
37
Define: Exocytosis
When materials leave the cell by the membrane "spitting it out"
38
Define: Endocytosis
A process in which cell takes in materials from the outside by engulfing and fusing them with its plasma membrane
39
Define: Phagocytosis
The process of engulfing and ingestion of particles by the cell or a phagocyte (e.g. macrophage) to form a phagosome (or food vacuole), which in turn fuse with lysosome and become phagolysosome where the engulfed material is eventually digested or degraded and either released extracellularly via exocytosis, or released intracellularly to undergo further processing.
40
Define: Pinocytosis
A process of taking in fluid together with its contents into the cell by forming narrow channels through its membrane that pinch off into vesicles, and fuse with lysosomes that hydrolyze or break down contents.
41
Define: Receptor-mediated endocytosis
Receptor-mediated endocytosis, also called clathrin-mediated endocytosis, is a process by which cells absorb metabolites, hormones, proteins – and in some cases viruses – by the inward budding of the plasma membrane.
42
Define: Cell junctions
Intercellular connections between adjacent cells, resulting in varying degrees of fusion and specialized functions of animal tissues
43
Define: Function of membrane proteins
Membrane proteins perform a variety of functions vital to the survival of organisms: Membrane receptor proteins relay signals between the cell's internal and external environments. Transport proteins move molecules and ions across the membrane. ... Cell adhesion molecules allow cells to identify each other and interact.
44
Define: Tight junction
A tight junction is a type of cell junction wherein the membranes of two neighboring cells join to form a barrier to larger molecules and water that pass between the cells. As a barrier, tight junctions help maintain the polarity of cells and the osmotic balance.
45
Define: Desmosome
A type of cell junction made up of desmosome-intermediate filament complexes, which in turn consists of cadherin proteins, linker proteins, and keratin intermediate filaments
46
Define: Gap junction
A type of cell junction characterized by the intercellular channel that is formed in between neighboring cells, and allows direct communication between cells, i.e. allowing small molecules, ions, and electrical impulses to move between cells without passing the outside of cells
47
Define: Intermediate filaments
An intermediate filament is comprised of two anti-parallel helices or dimers of varying protein sub-units. It may be composed of any of a number of different proteins and form a ring around the cell nucleus. Intermediate filaments are stretchable. They can be extended manifold their initial length. With the exception of nuclear lamin, the intermediate filaments are cytoplasmic.
48
Define: Extracellular matrix
The extracellular matrix is the non-cellular portion of a tissue. It is a collection of extracellular material produced and secreted by cells into the surrounding medium. The main function of the extracellular matrix is to provide structural and biochemical support to the surrounding cells.
49
Define: Ribosomes
A minute, sphere-shaped particle composed of protein and ribonucleic acid (RNA) that serves as the site of protein synthesis
50
Define: Transcription
The process of transcribing or making a copy of genetic information stored in a DNA strand into a complementary strand of RNA (messenger RNA or mRNA) with the aid of RNA polymerases
51
Define: Translation
A step in protein biosynthesis where a genetic code from a strand of mRNA is decoded to produce a particular sequence of amino acids
52
Define: Self replication
Self-replication is any behavior of a dynamical system that yields construction of an identical copy of itself. Biological cells, given suitable environments, reproduce by cell division. During cell division, DNA is replicated and can be transmitted to offspring during reproduction.
53
Define: Chromosomes
A structure within the cell that bears the genetic material as a threadlike linear strand of DNA bonded to various proteins in the nucleus of eukaryotic cells, or as a circular strand of DNA (or RNA in some viruses) in the cytoplasm of prokaryotes and in the mitochondrion and chloroplast of certain eukaryotes
54
Define: Chromatin
A chromatin is a macromolecule made up of DNA or RNA and proteins. It turns into a chromosome when it becomes condensed during cell division. Its functions are to package DNA into a smaller volume to fit in the cell, strengthen the DNA to allow mitosis and meiosis, and to serve as a mechanism to control expression. The chromatin is found within the cell nucleus of eukaryotic cells.
55
Define: Gene
A gene is the fundamental, physical, and functional unit of heredity. It is because a gene is comprised of nucleotides (on a specific site on a chromosome) that is responsible for the physical and heritable characteristics or phenotype of an organism.
56
Define: Gene expression
The conversion of the information from the gene into mRNA via transcription and then to protein via translation resulting in the phenotypic manifestation of the gene.
57
Define: mRNA
Messenger ribonucleic acid A ribonucleic acid RNA that carries the genetic code for a specific protein, and conveys this code from the DNA to the ribosome
58
Define: tRNA
Transfer ribonucleic acid A ribonucleic acid RNA involved in protein synthesis, particularly transporting specific amino acid to the ribosome to be added onto the growing polypeptide chain
59
Define: rRNA
Ribosomal ribonucleic acid Ribosomal ribonucleic acid (rRNA) is a ribonucleic acid that, together with the ribosomal proteins, makes up the ribosome. Ribosomal RNA does not carry the code in making proteins. Rather, it forms the two subunits (i.e. large subunit and small subunit) of a ribosome.
60
Define: Genetic code
relationship between the sequence of bases in nucleic acid and the order of amino acids in the polypeptide synthesised from it. A sequence of three nucleic acid bases (a triplet) acts as a codeword (codon) for one amino acid.
61
Define: Polymerisation
The act of process of forming a polymer, especially by chemical reactions that join monomers together in a chain or a three-dimensional network
62
Define: Endoplasmic reticulum
Endoplasmic reticulum (ER), in biology, a continuous membrane system that forms a series of flattened sacs within the cytoplasm of eukaryotic cells and serves multiple functions, being important particularly in the synthesis, folding, modification, and transport of proteins .
63
Define: Rough Endoplasmic reticulum (RER)
The presence of ribosomes on rER is an indication that the latter is involved in protein synthesis and secretion. Since rER has ribosomes attached to its surface it is therefore involved in protein synthesis and protein folding, as well as the shuttling of proteins to the Golgi apparatus where the nascent protein undergoes maturation.
64
Define: Mitosis
The process where a single cell divides resulting in generally two identical cells, each containing the same number of chromosomes and genetic content as that of the original cell
65
Define: Spindle
A collection of minute fibers composed of microtubules, which are prominent during cell division, as mitotic spindle or mitotic apparatus''.
66
Define: Spindle
A collection of minute fibers composed of microtubules, which are prominent during cell division, as mitotic spindle or mitotic apparatus''.
67
Define: Nuclei
Plural form of nucleus, i.e. the large, membrane-bounded organelle that contains the genetic material, in the form of multiple linear DNA molecules organized into structures called chromosomes
68
Define: Nuclear membrane
The nuclear envelope, also known as the nuclear membrane, is made up of two lipid bilayer membranes which in eukaryotic cells surrounds the nucleus, which encases the genetic material. The nuclear envelope consists of two lipid bilayer membranes, an inner nuclear membrane, and an outer nuclear membrane.
69
Define: Prokaryotes
Any of the group of organisms primarily characterized by the lack of true nucleus and other membrane-bound cell compartments: such as mitochondria and chloroplasts, and by the possession of a single loop of stable chromosomal DNA in the nucleiod region and cytoplasmic structures, such as plasma membrane, vacuoles, primitive cytoskeleton, and ribosomes.
70
Define: Energy production
A
71
Define: The Membranes of Chloroplasts
The chloroplast has at least three membrane systems: outer membrane, inner membrane, and thylakoid system. The thylakoids are disk-shaped structures that function as the site of photosynthesis. It is because embedded in the thylakoid membrane is the antenna complex consisting of proteins, and light-absorbing pigments, including chlorophyll (the green pigment) and carotenoids. The chlorophyll is capable of absorbing light energy for use in photosynthesis. The high amounts of chlorophyll give chloroplast a green color, making it easily recognizable from the other plastids.
72
Define: Energy production
Plants produce energy from light through a process known as photosynthesis. Eukaryotic cells use their mitochondria to generate ATP through a process called cell respiration. Respiration that uses oxygen is called aerobic respiration while oxygen-less respiration is called anaerobic respiration.

Biology 95F (4 decks)

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