Chapter 4: Eukaryotic Cells Flashcards

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1
Q

Endosymbiotic Theory

A

series of sequentail, cell merging events between an ancient eukaryotic ancestor and certain prokaryotes; mitochondria evolved from an engulfed nonphotosynthetic prokaryote; chloroplast evolved from an engulfed photsynthetic prokaryote (cyanobacterium)

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2
Q

What is some of the evidence supporting endosymbiotic theory?

A

mitochondria and chloroplasts have their own circular DNA;, 70S ribosomes, double membrane structures, similar size to bacteria, ability to replicate by a process similar to binary fission, genes resembling certain bacterial gnees

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3
Q

Eukaryotic Cells

A

plants, animals, protists, fungi, larger in size and more complex than prokaryotic cells; larger genomes; multiple linear chromosomes

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4
Q

Membrane Bound Organelles

A

eukaryotic cells have a defined nucleus; a variety of other membrane bound organelles; mitochodria, chloroplast

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5
Q
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6
Q
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6
Q

Cell Division in Eukaryotes

A

eukaryotic cells can exhibit sexual or asexual reproduction; before a cell divides it must copy it genetic material; cell division is longer in eukaryotes because they have a larger genome and organelles to replicate

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7
Q

Mitosis

A

generates two genetically identical offspring from one parent cell; offspring cells maintain the same number of chormosomes as the parent cell; clones

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8
Q

Meiosis

A

involved in sexul reproduction; consists of two cell division stages; one parent cell produces four gametes; gametes are haploid; crossing over allows for genetic recombination

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9
Q

Endocytosis

A

imports things into the cell; plasma membrane fold around extracellular substances; membrane pinches off forming endocytic vesicles containing substances; pinocytosis, phagocytosis, and receptor mediated endocytosis

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9
Q

Exocytosis

A

exports things out of the cell; vesibles deliver their contents to the plasma membrane

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10
Q

Pinocytosis

A

cell drinking; endocytosis of dissolved substances in small vesicles

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11
Q

Phagocytosis

A

cell eating; endocytosis of undissolved substances

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12
Q

Phagocytosis (cont)

A

specialized immune system cells (macrophages); cells engulfs its target (the phagosome); phagosome fuses with a lysosome containing hydrolytic enzymes; fusion = phagolysosome; hydrolytic enzymes destroys most cells and viruses; waste products are expelled

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13
Q

Receptor Mediated Endocytosis

A

ligands (hormones, nutriens, pathogens, etc) bind to specific cell surface receptors; inner surface of the plasma membrane is coated with clathrin; clathrin polymerizes forming a pit; clathrin-coated pit pinches off; forms a clathrin coated vesicle; sheds the clathrin coat; fuses with an endosome; altered pH separates ligand and receptor; ligand and recepteor are sorted and delivered

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14
Q

Animals

A

multicellular organisms; do not carry out photosyntehsis; obtain organie carbon from nutrients; ~7.5 million animal species; include parasitic worms (helminths) and arthropods

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15
Q

Helminths

A

paraisitc worms (roundworms and flat worms); complex life cycles; usually spead in a microscopic form; WHO estimates half the worlds population is infected with some type of helminth

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16
Q

Plants

A

multicellular organisms; more than290000 species; carry out photosynthesis (contain chloroplasts); make their own organic carbon using light energy; vegetation can serve as a vehibcle for infectious pathogens

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17
Q

Fungi

A

mroe than 600000 different species; most are multicellular; yeasts are unicellular; do not carry out photosynthesis; absorb nutrients from their environemt; include pathogens and saprobes

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18
Q

Hyphae

A

most fungi grow as a collecion of tubular structures

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19
Q

Septate Hyphae

A

divisions between each cell in the filament so it appears as a string of individual cells

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20
Q

Aseptate Hyphae

A

do not have divisions and appear as a long continuous chain with amny nuclei

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21
Q

Dimorphic Fungi

A

cycle between having hypahe and living as a yeast like form; many pathogenic fungi are dimorphic

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22
Q

Asexual Spores

A

arise from mitosis (no genetic variation); include conidiospores and sporangiospores

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23
Q

Sexual Spores

A

arise from meiosis (results in genetic variation); include: zygospores, ascospores, and basidospores

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24
Q

ADD IN EUKARYOTIC CHARTS INCLUDING HELMINTHS AND FUNGI

A
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25
Q

Fungal Diseases

A

called mycoses; occur in immunocompromised individuals (ex pneumocystis pneumonies AIDS patients), people who experience a disruption of their normal microbiota (ex yeast infections caused by candida)

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26
Q

Dermatophytes

A

fungal disease; true pathogens; infect skin, hair and nails; dermatophytic infections are tinea; tinea ungium aka dermatophytic onychomycosis; tinea pedia aka athletes foot

27
Q

Some fungi can stimulate allergies or produce…

A

mycotoxins; ex clavicep purpurea produces ergot toxin which is a potent neurotoxin that can lead to seizures, psychosis, nausea, vomiting, and even death

28
Q

Protists

A

diverse group of eukaryotes; unicellular, multicellular or multinucleated masses; autotrophs or heterotrophs; asexual or sexual reproduction; cell wall or no cell wall

29
Q

Examples of Protists

A

algae, slime molds, protozoans; though to represent evolutionary link to plants, fungi, and animals

30
Q

Examples of Protozoan Pathogens

A

toxoplasma gondii, trichomonas vaginalis, giardia spp.

31
Q

How are protozoans grouped?

A

based on their means of motility in their mature form; amoeboid, flagellated, ciliated, spore forming

32
Q

Amoeboid Protozoans

A

use pseudopods for movement; some are free living (amoeba proteus) and some are pathogenic (naeglera fowleri, acanthamoeba); entamoeba histolytica is the most common amoeboid infection in humans

33
Q

Flagellated Protozoans

A

flagella for motility; some are free living (euglena) and some are parasitic (trichomonas vaginalis, trypanosoma spp. , giardia lamblia)

34
Q

Ciliated Protozoans

A

ciliophora; use cilia for motility; common in aquatic environments; some are free living (paramecium) and some are parasites; balandtidium coli is the ciliated protozoan known to cause human disease

35
Q

Apicomplexa

A

spore forming protozoans; largest phyla of protozoans; move by gliding (no flagella, cilia, or pseudopodia); most are obligate intracellular parasites; complex life cycles that include sexual and asexual stages; three phases- mergony, gamogony, and sporogony

36
Q

Merogony

A

asexual stage of repoduction; merozoites are made by repeated asexual cell division

37
Q

Gamogony

A

sexual phase of reproduction; merozoites produce male and female haploid gametes by meiosis

38
Q

Sporogony

A

zygote made by gamete fusion divides to make sporozoites; typically the infective stage; then cycle starts again

39
Q

Apicomplexans are notorious…

A

human pathogens; toxoplasmosis (often spread by cats); malaria; cryptosporidiosis; microsporidiosis ; some members require arthropod vectors (like mosquitos) for part of their life cycle

40
Q

Plasma Membrane

A

serves as selective barrier; phospholipid bilayer structure; eukaryotic membranes contain many sterols

41
Q

Cell Wall

A

external to plasma membrane; helps maintain cell shpae; protects against mechanical and osmotic stress; fungi, plants, and certain protists have cell walls; lack peptidoglycan

42
Q

Eukaryotic Glycocalyx

A

most eukaryotes have a sticky extracellualr layer called a glycocalyx as their outermost layer; contains a diverse collection of carbohydrates, glycoproteins, and glycolipids

43
Q

Eukaryotic Flagella

A

built from tubulin; has microtubules (9+2 arrangement); surrounded by plasma membrane; microtubules sprout from a centriole; wave like motion (whips back and forth)

44
Q

Prokaryotic Flagella

A

flagellin protein; no microtubules; not membrane enclosed; hook and filament structure anchored by rings; rotatry/propeller movement

45
Q

Ribosomes

A

makes proteins; made of protein and ribosomal RNA (rRNA); eukaryotes have 80S ribosomes that are made of 40S and 60S subunit

46
Q

Ribosomes can be free or membrane associated

A

free in cytoplasm or bound to ER; can change from free to bound based on the protein production needs of the cell

47
Q

Bound Ribosomes

A

produce proteins that are destined for secretion from the cell

48
Q

Free Ribsomes

A

produces cytosolic proteins

49
Q

Cytoskeleton

A

dynamic (constantly being rebuilt and moved) and responsive intracellular network of protein fibers; helps maintain shape, facilitates movement, protects against external forces, directs transportation, coordinated cell division; made of microtubules, intermediate filaments and microfilaments

50
Q

Microtubules

A

hollow tubes; large; made of tubulin; roadways of the cell–proteins (kinesin and dynein) move cargo along microtubules; form spindle during cell division (helps separate chromosomes; usually arise from centrosome

51
Q

Intermediate filaments

A

rope-like fibers about 10nm in diameter; different proteins make up intermediate filaments; contribute tensile strength

52
Q

Microfilaments

A

fine fibers; smallest; made of actin; tend to assocaite with myosin; functions in muscle contraction, pinches cell apart, faciliates movement of pseudopodia

53
Q

Nucleus

A

DNA is loosely organized as chromatin; DNA floats in nucleoplasm; enclosed by nuclear envelope; has nuclear pores that control things in/out of nucleus

54
Q

Nucleolus

A

dense area in the nucleus; enriched with RNA; site where ribosomal subunits begin their development

55
Q

Endoplasmic Reticulum

A

continous with nuclear envelope at some points; essentiaal roles in protein and lipid production; many of the products made in the ER are destined for exportation to other organelles or for secretion; series of interconnected membranes that originate from the nuclear envelope ; smooth or rough

56
Q

Rough ER

A

millions of ribosomes on outer surface; proteins are directly inserted into the ER membrane or transported into the lumen; modifies proteins (clips, folds, addition organic/inorganix factors)

57
Q

Smooth ER

A

not associated with ribosomes; interlaced tubular appearance; involved in lipid production; important role in detoxifying substances

58
Q

Golgi Apparatus

A

vesicles that bud off the ER are often shuttled to golgi; series of cisternae (disc-like flattened sacs); coordinates with ER; modifies cellular proteins, build lipids, sorts and distributes finsihed products

59
Q

Transport Vesicles

A

move substances are the cell

60
Q

Secretory Vesicles

A

shuttle materials to the cell surface for discharge from the cell

61
Q

Lysosomes

A

contain hydrolytic enzymes that break down substances engulfed by the cell

62
Q

Peroxisomes

A

contain enzymes that break down fats and amino acids by oxidation, protect cells from toxic oxygen intermediates

63
Q

Vacuoles

A

conglomerate of many vesicles that merged to make a large membranous sac; contain mainly water and various organic and inorganic substances; vary in size and shape; common in plants and fungi

64
Q

Contractile Vacuoles

A

in some protists; regulates the osmotic pressure to avoid lysing when in a hypotonic environment

65
Q

Mitochondria

A

make ATP; make amino acids and vitamins; regulate cell division; carry out programmed cell death (apoptosis); impact a number of disease states; play a role in cancer and aging; smooth outer membrane; inner membrane contain critae; matrix

66
Q

Chlrorplasts

A

allow the cell to harvest energy from sunlight using light collecting pigments; inner and outer membrane; thylakoids stacked in grana; stroma