Chapter 1: The Cell Flashcards

Question

distribution of organelles

Answer 1

Different cells have different organelle amounts Cells that require locomotion (i.e. sperm) have high concentration of mitochondria (energy!) Cells involved in secretion (pancreatic/endocrine tissue) have high concentration of RER and Golgi apparatus Transport cells (RBC's) have no organelles at all

Answer 2

Contain hydrogen peroxide Allow for breakdown of very long fatty acid chains via beta-oxidation Synthesis of phospholipids Contain some pentose phosphate pathway enzymes

Answer 3

Maintain structure/shape of cell Transport of materials around cell Components: microfilaments, microtubules, and intermediate filaments

Answer 4

Made of rods of actin Actin filaments organized into bundles & networks--resistant to breakage and compression Cell protection Filaments can also use ATP to generate force for movement by interacting with myosin (muscle contraction) Play role in cytokinesis--division of materials between daughter cells Pinch off connection between daughter cells

Answer 5

Hollow polymers of tubulin Primary pathways for vesicle carrying via motor proteins (kinesin and dynein) Make up cilia and flagella

Answer 6

Projections from cell primarily involved in material movement along surface of cell Mucus movement in respiratory tract Composed of microtubules

Answer 7

Involved in movement of cell itself Composed of microtubules made of tubilin 9+2 arrangement

Answer 8

Cilia and flagella microtubule arrangement 9 pairs of microtubules in outer ring 2 microtubules at center Only seen in eukaryotic cells of motility

Answer 9

Found in centrosome 9 microtubules with hollow center Organize mitotic spindle during mitosis when migrate to opposite poles of dividing cells Attach to chromosomes via kinetochores and exert pulling apart force on sister chromatids

Answer 10

``` Diverse group of filamentous proteins (keratin and desmin) Cell-to-cell adhesion Maintenance of cytoskeleton integrity Make cell more rigid Anchor organelles like nucleus ```

Answer 11

Cover body and line cavities Protection against pathogen invasion and desiccation Absorption, secretion, sensation Cells tightly joined together and to underlying basement membrane Polarized: one side interacts with lumen/outside world, the other side interacts with blood vessels and structural cells

Answer 12

Functional part of an organ Nephrons in kidney, hepatocytes in liver, acid producing cells in stomach Consists of epithelial cells Stroma is support structure (thanks to connective tissue)

Answer 13

One layer of cells

Answer 14

Multiple layers of cells

Answer 15

Appear to have multiple layers, really only has one

Answer 16

Supports body and provides framework for epithelial cells to carry out functions Main contributors of stroma (support structure) when epithelial cells contribute to parenchyma of organ Bone, cartilage, tendons, ligaments, adipose tissue, blood Most cells produce and secrete materials like collagen and elastin to form extracellular matrix

Answer 17

Simplest of all organisms No membrane bound organelles Single circular molecule of DNA concentrated in nucleoid region DNA not coiled around histones No membrane bound organelles, but may have plasmids 30S and 50S ribosomes

Answer 18

Where circular DNA molecule in prokaryotes is concentrated This DNA not carried around histones May have plasmids

Answer 19

Single celled organisms that are visually similar to bacteria Contain genes and metabolic pathways that are more similar to eukaryotes (start translation w/ methionine, contain similar RNA polymerases, associate DNA with histones) Extremophiles Resistant to many antibiotics Divide by binary fission or budding

Answer 20

All contain cell membrane and cytoplasm Some have flagella and fimbriae (analogous to cilia) Outnumber human cells in the body 10:1 Do not form multicellular organisms, so responsible for protecting self from environment

Answer 21

Bacteria in the gut produce vitamin K (clotting) and biotin Some bacteria prevent overgrowth of other bacteria Babies are not colonized with bacteria yet, so given a vitamin K shot at birth to aid in clotting

Answer 22

Require oxygen for metabolism

Answer 23

Use fermentation or other metabolism that does not require oxygen

Answer 24

Cannot survive in oxygen containing environment

Answer 25

Can use oxygen for aerobic metabolism if present or can switch to anaerobic metabolism if no oxygen

Answer 26

Unable to use oxygen but not harmed by it

Answer 27

Cell wall + cell membrane in prokaryotes

Answer 28

In prokaryotes, forms outer barrier of cell Provides structure and controls movement of solutes into and out of bacterium Allows for maintenance of concentration gradient relative to environment Two types of cell walls: (dependent on Gram staining process) a) gram positive b) gram negative

Answer 29

``` Absorbs crystal violet stain Appears deep purple Consist of thick layer of peptidoglycan Provides protection from host organisms immune system Also contains lipoteichoic acid No outer membrane ```

Answer 30

Polymetric substance made from amino acids and sugars Present in gram+ bacteria, and gram- (but in small amounts) Penicillin targets the enzyme that catalyzes the cross-linking of peptidoglycan--if a gram+ cell can't cross-link cell wall, it's no longer an effective barrier

Answer 31

Present in gram+ bacteria | Function unknown, but human immune system may be activated by exposure to this chemical

Answer 32

Do not absorb crystal violet stain Absorb safranin counterstain, and appear pink-red Thin layer of peptidoglycan Contain lipopolysaccharides and phospholipids

Answer 33

Ability of a cell to detect chemical stimuli and move towards or away from them

Answer 34

Made of flagellin | Composed of hook, filament, and basal body

Answer 35

Part of flagella | Hollow, helical structure composed of flagellin

Answer 36

Complex structure that anchors the flagellum to the cytoplasmic membrane and is also the motor of the flagellum, rotating at rates of up to 300 hz

Answer 37

Connects filament and basal body so that, as basal body rotates, it exerts torque on the filament, which can thereby spin and exert the bacterium forward

Answer 38

Small circular structures on which DNA acquired from external sources may be carried This DNA is not vital to survival of bacterium, but may carry advantage (like antibiotic resistance) May contain virulence factors, which increase how pathogenic it is

Answer 39

Simple form of asexual reproduction seen in prokaryotes Circular chromosome attaches to cell wall and replicates while cell continues to grow Plasma membrane pinches towards midline to produce two identical daughter cells Proceeds more rapidly than mitosis, because requires fewer events

Answer 40

Traits that increase how pathogenic a bacterium is, like toxin production, projections that allow it to attach to cells, or evasion of immune system Carried in plasmids

Answer 41

Subset of plasmids Capable of integrating into genome of bacterium Help recombination and thus evolution of bacterial species over time

Answer 42

Form of recombination process Results from integration of foreign genetic material into host genome Often from lysed bacteria that spill genetic contents into vicinity of bacteria capable of bacterium capable of transformation Most gram- rods

Answer 43

Form of recombination process Bacterial form of mating Two cells form conjugation bridge that allows for the transfer of genetic material Transfer is unidirectional (from donor male (+) to recipient female (-)) Bridge is made from appendages called sex pili found on donor male Rapid acquisition of antibiotic of antibiotic resistance or virulence factors throughout a colony F factor example: Bacteria that possess F factor are called F+ cells; without are F- F+ replicates F factor during conjugation and donates to F- F- is now F+

Answer 44

Certain plasmids that are necessary for the formation of sex pili which creates the conjugation bridge Relevant to conjugation Best studied sex factor is the F (fertility) factor in E. coli

Answer 45

Best studied sex factor (in E. coli) Type of plasmid Bacteria that possess it are called F+ cells; without are F- F+ replicates F factor during conjugation and donates to F- F- is now F+

Answer 46

Type of recombination process Only recombination process that requires a vector--a virus that carries genetic material from one bacterium to another Viruses can accidentally trap segment of host DNA during assembly inside host during reproduction, and when bacteriophage infects another bacterium, it can release this trapped DNA into new host cell. This trapped DNA can integrate into genome, giving host additional genes.

Answer 47

Genetic elements capable of inserting and removing selves from genome. Observed in prokaryotes and eukaryotes

Answer 48

Bacteria adapt to local conditions

Answer 49

Bacteria grow exponentially | Resources reduced

Answer 50

Because resources were reduced in exponential phase, growth is slowed

Answer 51

environment can no longer support amount of bacteria

Answer 52

Are not living things; acellular Lack organelles and a nucleus Have genetic material, protein coat, sometimes an envelope containing lipids, tail sheath, tail fibers Genetic material may be SS or DS, circular or linear, RNA or DNA Lack ribosomes to carry out protein synthesis

Answer 53

virus protein coat

Answer 54

Surrounds capsid Sensitive to heat, detergents, and desiccation Easier to kill Composed of phospholipids and virus-specific proteins

Answer 55

Viral progeny | Released to infect additional cells

Answer 56

Viruses that target bacteria | Do not enter bacteria, but inject genetic material

Answer 57

Virus "syringe", that can inject genetic material into bacterium

Answer 58

help bacteriophage recognize and connect to correct host cell

Answer 59

Type of ssRNA virus | Implies the genome may be directly translated to functional proteins by the ribosomes by the host cells, just like mRNA

Answer 60

Type of ssRNA virus Requires the synthesis of an RNA strand complementary to the negative sense RNA strand, which can then be used as a template for protein synthesis Must carry an RNA replicase in the virion to ensure that the complementary strand is synthesized

Answer 61

Enveloped, ssRNA viruses in the family Retroviridae Virion usually carries 2 identical RNA molecules Carry reverse transcriptase, which synthesizes DNA from ssRNA The DNA then integrates into the host cell genome, where t is replicated and transcribed as if it were the host cell's own DNA. Only way to cure the infection is to kill the infected cell itself

Answer 62

Viruses can only bind to specific set of cells with proper receptors Enveloped viruses, like HIV, (*which enter the cell intact*) fuse with plasma membrane of cell, allowing entry of virion into host cell Bacteriophages only inset genetic material Host cell may misinterpret binding of virus to membrane as nutrient, etc, and bring virus into cell via endocytosis

Answer 63

Must go to the nucleus in order to be transcribed to mRNA | mRNA then goes to cytoplasm to be translated to protein

Answer 64

Genetic material stays in cytoplasm, where it's directly translated to protein by host cell ribosomes

Answer 65

Requires synthesis of complementary RNA strand via RNA replicase, which can then be translated to form proteins

Answer 66

Forms DNA through reverse transcription that travels to nucleus, where it can be integrated into host genome Must transcribe new copies of ssRNA from DNA that entered host genome to reenter viral genome

Answer 67

Bacteriophage makes maximal use of cells machinery with little regard for survival of host cell Once host cell is swollen with new virions, cell lyses, and other bacteria can be infected Bacteria in the lytic phase are termed virulent

Answer 68

Bacteria in the lytic phase | Swell with new virions and lyse

Answer 69

If virus does not lyse the bacterium, virus will be replicated as bacterium replicates because it is now part of host's genome Virus is known as provirus or prophage May enter lytic cycle via variety of factors

Answer 70

Infectious proteins Nonliving things Cause disease by triggering misfolding of other proteins Usually involves conversion of a protein from alpha-helical structure to beta-pleated sheet Drastically reduces solubility of protein, as well as ability of cell to degrade misfolded protein Eventually reduces function of cell Known to cause mad cow, Creutzfeldt-Jakob, and familial fatal insomnia

Answer 71

Small plant pathogens Consists of very short circular ssRNA Bind to RNA sequences and silence genes in the plant genome Prevent synthesis of necessary proteins and can subsequently cause metabolic and structural derangement in the plant cell Often plant pathogens, but some human pathogens, like Hepatitis D