Chapter 5 SG (go to flashcard)

lecture and textbook

Relate bacterial, archaeal, and eukaryotic cells to the last common ancestor

ALL 3 cells evolved from a different cell, precursor to prokaryotes/eukaryotes that biologist call the last common ancestor.

Ancestor was neither prokaryotic nor eukaryotic, but gave rise to all three types

List the types of eukaryotic microorganisms and say which are unicellular and which are multicellular.

Protozoa: Always unicellular
Fungi/Algae: May be unicellular or Multicellular

worms are multi but their egg are uni

Explain how endosymbiosis contributed to the development of eukaryotic cells.

Endosymbiosis: Relationship where a microorganism resides within a host cell and gives benefit to host cell

The large and small cells formed a symbiotic relationship where BOTH cells benefited. Some small cells were able to break down the large cell's wastes for energy.

Differentiate among the flagellar structures of bacteria, archaea, and eukaryotes.

Eukaryotic Flagellum- is 10x thicker, complex structure, covered by cell membrane extension, microtubules in 9×2 formation

Prokaryotic- moved in a propeller type fashion; Flagella are for moving to get them to nutrient and away from harm

Describe the important characteristics of a glycocalyx in eukaryotes.

composed of polysaccharides

appears as a network of fibers, a slime layer, or a capsule.

It provides protection and adherence of cells to surfaces.

List which eukaryotic microorganisms might have a cell wall.

fungi, algae

List similarities and differences between eukaryotic and bacterial cytoplasmic membranes.

Eukaryotic cell membranes contain sterols of various kinds, Sterols rigidity makes membranes more stable.

BOTH: Typical bilayer of phospholipids w/embedded protein molecules

Describe the main structural components of a nucleus

nuclear envelope: composed of 2 parallel membranes

Pores: formed by the connection of the inner and outer nuclear membranes

nucleolus: stains more intensely than the immediate surroundings because of its RNA content (RIBOSOMAL synthesis site)

chromatin: feature of the nucleoplasm in stained preparation is a network of dark fibers known as chromatin

How do the nucleus, endoplasmic reticulum, and Golgi apparatus act together with vesicles during the transport process.

-like an assembly line
-a segment of genetic code of DNA containing instructions for producing a protein is copied into RNA and passed out of the nuclear pores to the ribosomes on the RER.
-proteins are synthesized from rNA code and deposited into RER.
-protein products are transported to the Golgi apparatus into vesicles that can be used by the cell
-come of the vesicles contain enzymes to digest food, others are secreted to digest materials outside the cell,

Explain the function of the mitochondrion

generating ATP, metabolism “powerhouse of the cell”

hold the enzymes and electron carries of aerobic respiration

-extracts chemical energy contained in nutrient molecules and stores it as ATP

Explain the importance of ribosomes and differentiate between eukaryotic and bacterial types

-Eukaryote: Ribosomes synthesize all the protein

-Bacterial: -Can be found in short chains of polyribosomes
-Staging areas for protein synthesis

List and describe the three main fibers of the cytoskeleton.

-actin filaments: long thin protein strands . are most highly concentrated just inside the cell membrane. Responsible for contraction, crawling, pinching during cell division, and formation of cellular extensions

- intermediate filaments: ropelike structures. They are the structural reinforcement to cell and organelles. support structure of the nuclear envelope

-microtubules: long and hollow tubes that maintain the shape of eukaryotic cells with no cell wall, and they transport substances from one part of the cell to another

List three general features of fungal anatomy

ribosomes, mitochondria, a cell wall and cell membrane, a nucleus

Differentiate among the terms heterotroph, saprobe, and parasite

heterotroph- organism that gains their nutrients from organic materials.

saprobe- organism that acquires their nutrients from dead and decayed organisms. Moreover, they dwell in bottoms of the soil and water.

Parasite is an organism that actually lives on a living organism.

Explain the relationship between fungal hyphae and the production of a mycelium

A simpler answer: mycelium is the vegetative body of a fungus, constructed from a mass of interwoven hyphae

Describe two ways in which fungal spores are formed.

Asexual Spore Formation:
In this method, spores are produced by mitosis, meaning the offspring are genetically identical to the parent.

Sexual Spore Formation:
Sexual spores are produced through meiosis after the fusion of two compatible nuclei

List two detrimental and two beneficial activities of fungi (from the viewpoint of humans).

Detrimental: causing diseases and food spoilage;

Beneficial: used in antibiotics (like penicillin) and fermentation.

Note the protozoan characteristics that illustrate why they are informally placed into a single group.

Protozoa are single-celled eukaryotes (organisms whose cells have nuclei) that commonly show characteristics usually associated with animals, most notably mobility and heterotrophy

List three ways of locomotion exhibited by protozoa.

flagellar movement, ciliary movement, or amoeboid movement.

Explain why a cyst stage may be useful in a protozoan.

It helps to survive in adverse conditions.

The unfavorable conditions are like high temperature, scarcity of food, lack of oxygen, lack of moisture, and presence of toxic chemicals.

Give an example of a human disease caused by each of the four types of protozoa

1. Amoeboid protozoa: Entamoeba histolytica causes amoebiasis

2. Ciliated protozoa: Balantidium coli causes balantidiosis

3. Flagellated protozoa: Giardia lamblia causes giardiasis which develops intestinal distress. This disease spreads by contaminated water and food.

4. Nonmotile protozoa: Plasmodium vivax of this class causes malaria in humans.

List the two major groups of helminths and provide examples representing each body type.

Platyhelminthes or flatworms consist of blood fluke, pork tapeworm etc.

Nematodes or roundworms consist of ascaris, ex. guinea worm, trichina worm, pin worm etc.

Summarize the stages of a typical helminth life cycle.

Must transmit and infective form (egg or larva) to the body of another host

Host in which the larva develops is known as the intermediate host

Adult hood and mating occur in the definitive host

Sources for human infection include food, soil and water and infected animals

1st Eukaryotes showed up on Earth How many years ago?

4 billion (textbook says 2-3 billion)

What is the name of the precursor that bacteria and eukaryotes evolved from? (neither were prokaryotes/eukaryotes)

last common ancestor (LCA)

this gave rise to eukaryote, bacteria/archaea separately

Where did organelles originate from?

originated from more primitive cells that were trapped in eukaryotic cell

TRUE/FALSE: 1ST Primitive eukaryotes were single celled and independent that were specialized to perform a function in colony.

True

Complex, multicellular organism evolved when cells lost….

the ability the survive away from the colony (tissues/organs)

Features found in ALL EUKARYOTIC CELLS

Cytoplasmic membrane, cytoskeleton, endoplasmic reticulum, Golgi apparatus, glycocalyx, mitochondria, nucleus, vacuoles

Features found in CELLS OF SOME EUKARYOTIC GROUPS

cell wall, locomotor appendages, chloroplasts

Eukaryotic flagella vs. Bacteria flagella (the answer will only pertain to eukaryotic)

10x thicker. complex structure

covered by a cell membrane extension

long sheathed cylinder with hollow microtubules in 9+2 arrangement

whipping motion in locomotion

Cilia (Eukaryote cells)

similar structure to flagella, shorter and numerous hair like

found in a single protozoa group and certain animal cells

function as feeding/filtering structures on some cells

Moves in an oarlike rowing motion

The Glycocalyx

outermost boundary comes into direct contact with the environment

“extracellular matrix”

composed of polysaccharides

role in cell recognition/protection

The Cell Wall

found in fungi/algae

rigid and provides structural support/shape

different chemical composition than bacterial cell wall

Chitin or cellulose is structural support for…?

fungi

The Cytoplasmic Membrane

bilayer of phospholipids embedded with protein molecules

(has its own glycoprotein to relay information)

stabilizes eukaryotic membranes

The Nucleus

a compact sphere

separated from the cytoplasm by the nuclear envelope

The NUCLEOLUS is here

• stains more intensely due to RNA content

• site for ribosomal RNA synthesis

Mitosis and Meiosis are the _____ __ ______ ____ within eukaryotic cells.

copying of genetic material

Eukaryotes keep their genetic material in the form of chromosomes. What is the name of the material that makes up the eukaryotic chromosomes?

chromatin

Chromatin

contains units of genetic information in the cell

long linear DNA molecules bound to histone proteins (loose)

visible in meiosis

Meiosis

(production of sex cells)

Mitosis Phases

Interphase, Prophase, Metaphase, Anaphase, Telophase

Early Prophase

Chromatin condenses to form visible chromosomes.

Each chromosomes and sister chromatids are held together by a centromere.

Centrosome and its’s duplicated start synthesizing microtubules that push centrosome to mitotic spindle.

Asters (microtubules) radiate from centrosome

Late Prophase:

Nuclear envelope breaks apart

microtubules attach to an area on centromeres called kinetochore and pull chromosomes to the equator of cell

Remaining kinetochore push against each other, making the cell poles to move farther apart

Metaphase

Centromeres of chromosomes are precisely aligned at the cell equator

The imaginary plane midway between the poles is called metaphase plate

Anaphase (shortest phase)

centromeres of chromosomes split at the same time

sister chromatids——→separate chromosomes

chromosomes are pulled to their respective poles by motor protein of kinetochores (one chromosome of each original pair goes opposite poles)

non-kinetochores microtubules keep forcing poles apart

Telophase- begins when chromosome movement stops

each set of chromosomes at opposite ends of cell will uncoil to form chromatin

nuclear membrane form around each chromatin mass

nucleoli reappear, spindle disappears

Endoplasmic Reticulum

microscopic series of tunnels used in transport and storage

Rough Endoplasmic Reticulum (RER)

ribosomes attached on surface

proteins held for packing and transport

Smooth Endoplasmic Reticulum

no ribosomes

synthesis and storage of non protein molcules

Golgi Apparatus

site of protein modification/transport

consists of a stack of flattened, disc-shaped sac

closely connected to endoplasmic reticulum (er)

Where it is close to the Golgi apparatus, ER forms _______ ______ that golgi apparatus picks up

transitional vesicles

Golgi apparatus adds ______ and lipids to proteins in transitional vesicles and pinches off _______ ____

polysaccharides, condensing vesicles

(then it is conveyed to lysosomes or transported to secretory vesicles)

cellular vesicle: LYSOSOME

originate from golgi apparatus, has a variety of enzymes

involved in intracellular digestion of food

protection against invading microorganisms

cellular vesicle: VACUOLES

membrane bound sac

has fluids or solid particles to be digressed, excreted, or stored

The origin of organelles (like mitochondria/chloroplast) is believed to be due to bacterial or archaeal cells ______ another descendant cell of LCA and then becoming a ________ part of that cell

parasitizing, permanent

Endosymbiosis could explain why mitochondria and chloroplasts have (3 things)

own circular DNA

70S ribosomes

own two-layer membranes

Mitochondria AKA THE POWERHOUSE OF THE CELL

(energy generator of the cell)

supply the bulk of energy of a cell

divide independently of the cell

circular strands of DNA

bacteria sized 70S ribosomes

Mitochondria structure:

Cristae: folds on inner membrane that hold enzymes and electron carriers of aerobic respiration

Matrix: holds ribosomes, DNA, and enzymes, and compounds used in metabolism

Chloroplasts: Photosynthesis Machines

turn sunlight energy into chemical energy by photosynthesis

role: main producers of all organic nutrients and oxygen gas

Ribosomes: Protein synthesizers

all throughout cell, scattered freely in cytoplasm/cytoskeleton, attached to RER

inside mitochondria/chloroplasts

arranged in polyribosomes (short chains of ribosome)

How are eukaryotic ribosomes similar to bacterial ribosomes in structure:

They have large and small subunits of ribo-nucleo-protein

The full size of ribosome is 80S (60s+40s subunits)

Cytoskeleton

functions: anchoring organelles, moving RNA and vesicles, allowing shape changes and movement

3 main types: actin filaments, intermediate filaments, microtubules (structure support)

look at this

look at this

Fungi

3-4 million species of fungi divided into 2 groups:

macroscopic fungi: mushrooms, puffballs, gill fungi

microscopic: molds, yeasts

Morphology of yeast cell

round to oval shape

uses asexual reproduction (yeast makes bacteria look tiny as shit)

Morphology of Hyphae

long, threadlike cells found in filamentous fungi or molds
Pseudo hypha: chain of yeast

Morphology of Dimorphic fungi

In cold environments, such as soils, these fungi appear as multicellular molds that are connected to a network of mycelium.

In the warm environment of a hosts body, they take on a single-celled yeast morphology.

Fungal Nutrition (fungi tend to be saprobes)

Heterotrophic: acquire nutrients from wide variety of substrates

Saprobes: obtain substrates from dead plants and animals (few can photosynthesize)

Parasites: live on the bodies of living animals or plants

Microscopic Fungi-grow loose in associations or colonies, 3 parts

Mycelium: the woven , intertwining mass of hyphae that makes up the body or colony of a mold

Septa: cross walls dividing hyphae into segments

Spore: fungal reproductive bodies

What are the functional types of Hyphae using the mold Rhizopus as an example?

Type of Hyphae	Function
Rhizoids	Anchoring & nutrient absorption
Stolons	Surface spread & connection
Sporangiophores	Asexual reproduction

Fungi have many complex and _____

successful reproductive strategies

Fungi have a simple _____ _____ of existing hyphae

outward growth

Fragmentation (reproduction of fungi)

is a separated piece of mycelium can generate a whole new colony

Primary reproductive mode (reproduction of fungi)

spore formation

Fungal spores should not be confused with the more_______

nonreproductive bacterial endospores

Fungal spores are

reproductive

The two types of asexual spore formation

sporangiospores: formed by successive cleavages within a sporangium

conidiospores/conidia: free spores not enclosed by a spore-bearing sac

purpose of sexual spore:

The main role is dispersal and genetic recombination.

Because important variations occur when fungi of different genetic makeup combine their genetic material

slight variations in the form/function are potentially advantageous to the adaption and survival of the species

Note: in the lecture she said we will spend VERY little time on plant and fungal genetic. cause it’s so fucking complicated

okay!

Heres an example of fungi life cycle (don’t worry so much about it)

okay!

Most human fungal infection occurs through accidental contact with

soil, water, or dust

Infectious/ Pathogenic Fungi are casued by

Community acquired infections caused by environmental pathogens

hospital-associated infections caused by fungal pathogens in clinical settings

Opportunistic infections caused by pathogens infecting already weakened people with a

transplant, cancer, and HIV+

Medical Conditions caused by Fungi

candidiasis

tinea vesivolor

ringworm (tinea corporis)

histoplasmosis

fungi are also involved in other medical conditions besides infections

allergies and neurological conditions due to toxin production

Beneficial impacts of fungi

• role in decomposing organic matter and returning essential minerals to soil

• form stable associations with plant roots that increase water/nutrient absorption

• production of antibiotics, alcohol, organic acids, vitamins

• flood flavoring

• alcohol in beer wine, gas that causes bread to rise

Algae and protozoa have been traditionally combined into the KINGDOM Protista and these two subdivisions:

Subkingdom algae

subkingdom protoza

What is a protist?

any eukaryotic unicellular or colonial organism that lacks true tissues

What is algae? (photosynthetic protists)

group of photosynthetic organisms, widespread inhabitants of fresh and marine water

Plankton?

floating community of microscopic organisms, essential role in aquatic food web, produce 70% if earth’s oxygen

Primary medical threat from algae, is through ingestion of toxins during a

red tide

Protozoa include about ______ species

65,000

The predominant habitats for protozoa are:

fresh and marine water

soil

plants

animals

While most members are harmless, a few species are ______ responsible for hundreds of millions of infections in humans per year.

parasites

Protozoan Form: they are single cells containing all major eukaryotic organelles BESIDES

chloroplasts

Protozoan Organelles can be highly specialized into structure similar to:

mouth

digestive systems, reproductive tracts

legs-in means of locomotion

Protozoan Nutrition

heterotrophic and require their food in complex organic form

Protozoan free-living species nutrition

scavenge dead plant or animal debris

graze on live cells of bacteria and algae

Protozoan parasitic species nutrition:

live in fluids of the host such as plasma and digestive juices

may actively feed on tissues