Bio B3A Exam 2

what are the general features of a prokaryote?

-unicellular

-lack nucleus

-small in size

-variety of shapes and arrangements

coccus

-circular shape

-equal width and height

bacillus

longer than they are wide

spirili

-vibrio

-wavy cell

what is the purpose of the plasma membrane?

regulates what goes in and out of the cell

what is the plasma membrane composed of?

phospholipid layer (hydrophilic head, hydrophobic tail)

How would you describe the plasma membrane?

fluid and stretchable

What can flow freely through the plasma membrane?

cell particles, oxygen, and carbon dioxide

What is the purpose of the cell wall?

-to protect the plasma membrane

-provides structure and shape

-prevents cell from rupturing in a hypotonic environment

hypotonic

having deficient tone or tension/lower concentration of solute compared to solute

What is the cell wall composed of?

peptidoglycan

What is the difference between gram positive and gram negative cells?

-gram positive has thick layer of peptidoglycan

-gram negative has thin layer of peptidoglycan w/ second, thicker layer of lipopolysaccharide (outer membrane)

What does the outer membrane of a gram negative cell contain?

impermeable channels of porings which allow certain small molecules to pass through

What color will a gram stained gram positive cell be?

purple

What color will a gram stained gram negative cell be?

pink

What are the steps for a gram stain?

1. Fixation

2. Crystal Violet

3. Iodine Treatment

4. Decolorization

5. Counterstain Safranin

What color do cells start out before a gram stain?

clear

capsule

neatly organized and firmly attached

What does a capsule contribute to?

virulence (increases bacteria's ability to cause disease)

-ex: streptococcus pneumonia and klebsiella pneumonia

flagella

long filamentous appendage

-used for motility (locomotion)

fimbriae

-shorter, straighter, and thinner than flagella

-allows attachment

-aids in forming biofilm

-help bacteria adhere to epithelial surfaces/mucous membranes

cytoplasm

-the substance inside the plasma membrane

What does cytoplasm consist of?

cytosol, nucleotide, plasmids

cytosol

water, ions, proteins, carbs, lipids, waste

nucleoid

contains bacterial chromosome

-single, continuous, circular, double stranded DNA

-no nuclear envelope

-attached to plasma membrane

plasmids

small circular DNA molecules

-not connected to main chromosome

-replicate independently

-not crucial for survival under normal conditions

How are endospores formed?

when bacteria in prokaryotes become stressed and essential nutrients are depleted

resting cells

dominant for centuries

What are endospores resistant to?

desiccation, heat, chemicals

How exactly do endospores work?

they germinate like a seed when environmental conditions increase, and they preserve DNA in the endospore

binary fission

a form of asexual reproduction in which an organism divides into two, each part carrying one copy of genetic material

importance of bacterial gene transfer

-increases genetic variation

-horizontal gene transfer

-donor cell contributes part of genome to recipient cell

horizontal gene transfer

from 1 individual to another individual of the same generation

What are the 3 types of bacterial gene transfer?

transformation, transduction, conjugation

bacterial transformation

uptake of naked DNA from the environment

-competent bacteria

competent bacteria

can take naked DNA from environment

bacterial transduction

transfer of genetic material via a bacteriophage

bacteriophage

a virus that parasitizes a bacterium by infecting it and reproducing inside it

bacterial conjugation

involves sex pilus

oxygen requirements for prokaryotes

obligate aerobes: must use oxygen for cellular respiration (cellular respiration)

obligate anaerobes: can't tolerate oxygen (fermentation)

facultative anaerobes: use oxygen if it's available to make ATP, if oxygen isn't available use fermentation or anaerobic respiration

What is nitrogen necessary for?

making amino acids and nucleic acids

heterocyst

nitrogen fixing cells possessed by the cyanobacterium Anabaena

cyanobacteria

-photoauthotrophs

-only prokaryotes that undergoes oxygen generating photosynthesis

-freshwater + marine ecosystems

-some have heterocysts for fixing nitrogen

What are the only prokaryotes that undergo oxygen generating photosynthesis?

cyanobacteria

What are the 3 parts of domain archaea?

extreme halophiles: live in high salt environments

extreme thermophiles: live in very hot environments

methanogens: release methane as a by-product of their metabolism

what is the role of pathogenic bacteria?

to control plant, animal, and bacteria populations

-not bad in natural communities

how can we treat bacterial disease?

selective toxicity, broad spectrum antibiotics, narrow spectrum antibiotics

selective toxicity

chemicals that harm bad bacteria, not specific parts of our cells

broad spectrum antibiotics

can kill both gram + and -

narrow spectrum antibiotics

can kill either gram + or -

How do you test for antibiotic resistance?

sensitivity testing

-agar plate w/ grown bacteria, test different antibiotics, measure zone of inhibition (cleared area around antibiotics)

-compare to known zones of inhibition

what are the steps for sensitivity testing?

1. culture bacteria

2. test against commonly used antibiotics (susceptible or resistant)

What are the different roles in research and technology?

CRISPR

production of useful medications

bioremediation

CRISPR

chops up viruses, used for DNA editing

bioremediation

using living organisms to cleanup environment

What is the most diverse of the 4 eukaryotic kingdoms?

kingdom Protista

Why are protists not fungi, plants, or animals?

because they lack the combinations of features to fit into those groups

What is the endosymbiotic theory?

a theory that tells the origin of the mitochondria and chloroplasts

-ancestral prokaryote -> infolding of plasma membrane (nucleus forming) -> endosymbiosis (cyanobacterium, aerobic bacterium) -> ancestral eukaryote

What are the general protist features?

-vary considerably in every other aspect

-unicellular, colonial, and multicellular groups

-most are microscopic, but some are huge

-all symmetries

-all types of nutrition

What are the different types of nutrition?

mixotrophic (heterotrophic + autotrophic), heterotrophic, and autotrophic

Protist Features - Cell Surface

-plasma membrane only (ex: amoeba)

-extracurricular (ECM) in some (ex: diatoms - silica shells)

Protist Features - Cysts

-environmentally resistant stage

1. dormant cell w/ resistant outer covering

2. used for disease transmission

Protists Features - Locomotion

1. Flagella

-long tail like structure

-one or more

2. Cilia

-shorter and more numerous than flagella

-propels protists through aquatic ecosystem

3. Pseudopodia ("false feet")

-extensions of cytoplasm

What are the complex life cycles that protists follow?

asexual reproduction, sexual reproduction, and alternation of generations

Asexual Reproduction

-typical mode of reproduction

-some species have an unusual mitosis:

mitosis - equal size daughter cells

budding - one daughter cell smaller

schizogony - cell division by several nuclear divisions; produces several individuals

What is mitosis?

a process of cell duplication, in which one cell divides into two genetically identical daughter cells

Sexual Reproduction

-meiosis is a major eukaryote innovation

-a type of cell division in sexually reproducing organisms that reduces the # of chromosomes in gametes (sex cells or egg and sperm)

-union of haploid gametes which are produced by meiosis

-advantage in allowing frequent genetic recombination

endosymbiosis

symbiosis in which one of the symbiotic organisms lives inside the other

Protists Classification and Phylogeny

1. Domain Eukarya

2. Kingdom Protista

3. Protists Supergroups

What are the different protist supergroups?

1. Supergroup Excavata

-Clade Diplompomonaddia

-Clade Parabasala

-Clade Euglenozoa

2. Supergroup Chromalveolata

-Subclade Phaeophyta

-Subclade Bacillariophyta

-Subclade Dinoflagellata

-Subclade Apicomplexa

-Subclade Ciliophora

3. Supergroup Rhizaria

-Subclade Foraminifera

-Subclade Radiolaria

4. Supergroup Archaeplastida

-Clade Rhodophyta

Clade Chlorphyta

5. Supergroup Amoebozoa

Supergroup Excavata

Clade Diplomonadida

Clade Parabasala

Clade Euglenozoa

Supergroup Excavata - Clade Diplomonadida

-Unicellular

-Move with flagella

-2 nuclei

-Giardia

Pass via contaminated water (fecal oral contamination)

Cause diarrhea

Mitosome instead of mitochondria (anaerobic ATP generation)

Supergroup Excavata - Clade Euglenozoa

-Among the earliest eukaryotes to possess mitochondria

-⅓ have chloroplasts and are autotrophic

-May become heterotrophic in the dark

-Others lack chloroplasts and are heterotrophic

-All have a flexible pellicle

-Allow euglenoids to change shape

-No sexual reproduction

Euglena

-1 or 2 flagella

-Second very short

-Contractile vacuoles - collect excess water

-Some are mixotrophic

Trypanosoma

-Unique, single mitochondrion

-Kinetoplast - single mass of DNA

-Cause human diseases

-Can change protective coat to evade host immune system

Trypanosoma brucei (African Trypanosomiasis)

-Animal parasites

-Sleeping sickness

-Transmitted by tsetse fly (feeds off blood)

-Vector - disease transmitting organism

-Africa

Diagnosis: Trypanosomiasis by microscopic examination of blood

-Daytime sleepiness and confusion

Trypanosoma cruzii (Chagas' Disease)

-Transmitted by kissing bug (parasite present in fecal matter; rub/scratch wound on skin)

-Americas

-Usually asymptomatic (no symptoms)

-Chronic disease = heart rhythm abnormalities

-Diagnosis: microscopic examination of blood

Romana's sign

(swollen eye from parasite)

Supergroup Archaeplastida - Clade Rhodophyta

-Red algae range from microscopic to very large

-Many live in deep waters

-Accessory photosynthetic pigments

Phycoerythrin (red), phycocyanin

Absorb blue and green light

-Cellulose cell wall

-Multicellular

-Chlorophyll A + B

-Commercial Uses:

Sushi wrappers, icecream, cosmetic thickener

Supergroup Archaeplastida - Clade Chlorophyta

-Modern chlorophytes closely resemble land plants

-Chloroplasts are biochemically similar to those of the plants

-2 Groups:

Chlorophytes

Charophytes

-Early green algae probably resembled Chlamydomonas reinhardtii

Individuals are microscopic

2 anterior flagella

Most individuals are haploid

Reproduces asexually and sexually

Has a holdfast

-Volvox

Multicellular chlorophyte

Hollow sphere

Biflagellated cells

--2 types of cells

Eyespot + flagella

2 flagella per cell

Forms colonies of cells

Ex: phytoplankton

-Spirogyra

Multicellular freshwater green algae

Chloroplasts in spiral pattern

Vegetative and photosynthetic

--Spirogyra Conjugation

Sexual reproduction

Link up cells, merge cells (genetic diversity)

Creates a zygospore

Goes through process similar to germination

Leftover filament is decomposed back into environment

--Ulva

Sea lettuce

Multicellular chlorophyte

Marine green algae

Holdfast: attach to specific spot (in light of abiotic factors such as currents)

--Chara

Also green algae (freshwater)

Gave rise to land plants (closest relative)

Can survive dried out

What have red, green, and brown algae adapted to attach to a specific area?

holdfast

Supergroup Amoebozoa

-Pseudopods

Extensions of plasma membrane to create "false feet" for feeding and movement

-Heterotrophic

Ex: zooplankton

-Unicellular

-Amoeba proteus

Feed on small living bacteria + protists

Free living amoeba (no host)

Marine and freshwater

Create storage areas called vesicles

-Entamoeba (Amoebic Dysentery)

Pathogenic

Human to human

Cysts excreted in feces

fecal/oral route

Amoebic dysentery

Diarrhea, abdominal pain, etc.

-Diagnosis: microscopic identification of cysts and trophozoites in the stool

Supergroup Chromalveolata - Clade Stramenopila; Subclade Phaeophyta; Subclade Bacillariophyta

-Brown algae, diatoms

-Very fine hairs on their flagella

-A few species have lost their hairs during evolution

--Subclade Phaeophyta

Brown algae

Kelp

Seaweed

Have a holdfast

Intertidal + deep waters (prefer more light)

Accessory pigment: fucoxanthin

Grow 1 to 2 feet per day

Size = up to 172 feet

Autotrophic

Multicellular

Important to marine ecosystems

They contain:

Stipe - stem like structure

Blade - lead like structure that absorbs sunlight

Air bladder - filled w/ gas, allows them to float towards sunlight

2 stages: developing sporophyte and gametophytes (egg + sperm)

Alternation of generations

Alternate between sporophyte and gametophyte

--Subclade Bacillariophyta

Diatoms (phytoplankton)

Photosynthetic, unicellular organisms (chlorophyll)

Unique double shells made of silica

Some move using raphe

2 long grooves lined with vibrating fibrils

Commercial Use:

Toothpaste, insect killer, diatomaceous earth

Supergroup Chromalveolata - Clade Alveolata; Subclade Dinoflagellata; Subclade Apicomplexa; Subclade Cilliophora

-Flattened vesicles called alveoli

-Dinoflagellates

-Apicomplexans

-Ciliates

--Subclade Dinoflagellata

Dinoflagellates

Unicellular w/ flagella

photosynthetic , heterotrophic, or mixotrophic

Live in aquatic environment

Some are luminescent

Phyto and zooplankton

Red tide

Bloom of dinoflagellates

Excess nutrients or organic material

Bioluminescent

Can be toxic (produce toxins as they grow)

Cellulose plate/shell

Transverse flagellum

Longitudinal flagellum

--Subclade Apicomplexa

Parasites of animals

Non-motile

Complex of organelles for host penetration at apex of cell

Plasmodium (single cell)

Causes malaria

Complex life cycle - sexual, asexual, different hosts

Eradication focused on eliminating mosquito vector, drug development, vaccine

200 million people infected

600,000 deaths each year

Toxoplasma gondii

Spread through the feces of cats

--Subclade Cilliophora

Aquatic

Unicellular

Heterotrophic

Ex: zooplankton

Cilia

Use for locomotion

Arranged in longitudinal rows or spirals around the cell

Pellicle - tough but flexible outer covering

2 types of nuclei

Micronucleus - w/o will reproduce asexually

Macronucleus - essential for physiological function

Conjugation -> fission (reproduction)

Supergroup Rhizaria - Subclade Foraminifera

-Foraminiferans

-Heterotrophic marine protists

-Use pseudopodia (made through cytoplasm moved out of holes in test)

Swimming, gathering material for test, and feeding

-Symbiotic algae provide food

-Pore-studded shells called tests, through which thin podia emerge

-Tests hardened with calcium carbonate

Test - hard outer covering around cell

-Microscope: dense, less intricate

-When they die, they sink to bottom (white in color)

Supergroup Rhizaria - Subclade Radiolaria

-Radiolarians

-Skeleton of silica

-Pseudopodia with microtubules

Used to filter microorganisms out of water

-Cytoplasmic streaming

-Also heterotrophic

-Microscope: more intricate, glass like, big holes

What is a plant?

-a multicellular autotrophic eukaryote

-cellulose cell walls

-waxy cuticle

Who do plants share a most recent common ancestor with?

green algae

What are the derived traits of plants?

alternation of generations, earliest land plants, more derived land plants (angiosperms), multicellular dependent embryos, and apical meristems

What is alternation of generations (plants)?

altering between gametophyte -> sporophyte

gametophyte stage is more commonly seen in ______ and sporophyte stage is more commonly seen in ______

seedless plants; seed plants

haploid (n)

1 copy of chromosomes

-essentially half the normal chromosome number found in a typical diploid plant, originating from a gamete (like a pollen grain or egg cell) and not undergoing fertilization; this means it has only one copy of each gene

diploid (2n)

2 copies of chromosomes

-plant body grows and eventually produces spores through meiosis

earliest land plants

ex: mosses

-large gametophyte

-small, dependent sporophyte

more derived plants (angiosperms)

-small, dependent gametophyte

-large sporophyte

multicellular dependent embryos

-dependent on parental tissue

-embryo: developing individual (baby)

apical meristems

-where plants make a lot of cells (rapid cell division)

-found in tips of roots and tips of stems

benefits of plants invading land (earliest land plants)

less competition for resources (ex: sunlight)

challenges for plants living on land (earliest land plants)

-dehydration (no longer surrounded by water)

-rooting (attach to rocks/soil)

-ATP through different source (oxygen via air not water)

-must establish new adaptations in order to survive

What are the different challenges plants have adapted to with living on land?

maintaining moisture within cells, obtaining resources from soil and air, transporting nutrients throughout the plant, supporting body against the forces of gravity present on land, transporting sperm, and dispersing offspring

How have plants adapted to maintaining moisture within cells?

cuticle

-hydrophobic layer that keeps water in cell

How have plants adapted to obtaining resources from soil and air?

need resources to carry out photosynthesis

-stomata

-leaves

-roots

stomata

allows for gas exchange

-carbon dioxide in and oxygen out

-guard cells regulate opening and closing of stoma

leaves

absorption of light energy by chloroplasts

-contain chlorophyll which is the dominant pigment in plants that absorbs light energy

-chlorophyll a and chlorophyll b

How have plants adapted to transporting nutrients throughout the plant?

through vascular tissue

-2 types: xylem and phloem