Lab 2: Prokaryotes- Bacteria and Cyanobacteria Structure and Mitotic Division of Eukaryotic Cells

Mitotic division

mitosis

Which organisms account for the earth’s biomass?

prokaryotes

Why do we study prokaryotes?

1. they form an important, neglected, unexplored, part of biodiversity

2. crucial role in ecosystems as decomposers

Heterophic

organisms that obtain their food from consuming other organisms

Decomposers

organisms that break down dead organic material, recycling nutrients back into the ecosystem (heterotrophic bacteria)

Primary producers

organisms that synthesize their own food, typically through photosynthesis, forming the base of the food chain (cyanobacteria)

Some of the first organisms to evolve the capacity for photosynthesis

Domain Bacteria

What do bacterial cells lack?

nuclear envelope, plastids, mitochondria, and other membrane bound organelles

What do bacteria cells consist of?

plasma membrane, cytoplasm with ribosomes, DNA(chromatin+associated proteins), and sometimes endomembranes

What do bacteria cell walls consist of?

peptidoglycan

Flagella

long, whip-like structures that enable locomotion in many prokaryotic organisms, allowing them to swim through liquids.

Unicellular

organisms that consist of a single cell, functioning independently

Are prokaryotes unicellular or multicellular?

unicellular, can form colonies

Filamentous

thread-like or consisting of long, thin filaments

Globular

spherical in shape

What are the shapes of colonies of bacteria/prokaryotes?

filamentous, globular, sheets/mats

Photosynthetic pigments of cyanobacteria

green chlorophyll a, yellow carotenoids, blue phycobilins

What does chlorophyll a do in cyanobacteria

photosynthesis

What do cartenoids and phycobilins do in cyanobacteria

help capture light in dark places and pass it to chlorophyll

What is all photosynthesis on Earth is done by?

chlorophyll a, aided by carotenoids

Heterocyst

specialized cell in cyanobacteria that is for nitrogen passing and storage

Why are heterocysts yellowish?

presence of cartenoids which help protect against UV damage

Why type of reproduction does bacteria have?

asexual (binary fission)

Binary Fission

asexual reproduction by the plasma membrane and cell wall grow inward, divides cell in half

Conjugation

asexual reproduction by portions of DNA exchanging between bacterial cells through a temporary connecting pilus (conjugation pilus)

What are critical functions of heterotrophic bacteria?

1. fixation of atmospheric nitrogen

2. nutrient cycling

Why is cyanobacteria important?

1. largest form of prokaryotes to produce oxygen

2. frequently confused with green algae

3. occur as symbionts frequently with fungi

Symbionts

organisms in a symbiotic relationship, often living closely with another species to benefit each other

In most cases the cell wall of bacteria contain

peptidoglycan

True or False: Only eukaryotes are motile

False

Are bacteria and algae with phycobilin pigments found in sunnier or shadier places, why?

shadier, phycobilin pigments capture light in dark places to pass to chlorophyll to do photosynthesis and also fall apart from light

What’s one way heterotrophic bacteria feed?

absorption on nutrient substances

Three forms of bacteria cell shape

coccus, bacillus, and spirilla

Spheroid-shaped bacteria

coccus (pl. cocci)

Rod-shaped bacteria

bacillus (pl. bacilli)

Spiral-shaped bacteria

spirilla (pl. spirilli)

Two species of bacteria in yogurt

Lactobacillus bulgaricus (rod-shaped) and Streptococcus thermophilus (spherical)

What shape is this bacteria?

Bacilli

Are these eukaryotes or prokaryotes?

prokaryotes

What shape is this bacteria?

cocci

What shape is this bacteria?

spirilli

What domain of life does Gloeocapsa belongs to?

Domain Bacteria

What type of colonies do Gloeocapsa form?

globular colonies

Filamentous colonies

filaments; strings of cells

False branching

two filament ends continuing to grow at an angle and away from the rest of the main filament

True branching

formed by lateral divisions in cells of the main filament and occurs in different planes all around the main filament

True or False: Only members of the Domain Eukarya are autotrophic

false, prokaryotes can also be autotrophic

Chlorophyll a evolved in Domain

bacteria, prokaryotes

Name one way in which cyanobacteria are important to forests

symbiotic relationship with fungi

Name the structure at the pointer under the microscope, what is it’s function, and what domain is the organism in?

1. Heterocyst

2. Nitrogen fixation

3. Domain Bacteria

Is the example under the microscope pointer true or false branching?

false branching

What is the name of the structure at the pointer under the microscope? What is it’s purpose?

extracellular sheaths. they

1. attach to substrate to each other

2. help cells communicate to one another

3. protect them from the environment

What do plant cells consist of?

nucleus, membrane-bound organelles, cellulose, protoplast

Protoplast

delimited by cell(plasma) membrane, contains the cytoplasm and the nucleus

Nuclear envelope

2 membranes that surround the nucleus and contains 1+ dense regions of nucleoli

Nucleoli (pl. nucleolus)

centers of ribosomal RNA production

Name the green organelles inside this cell

chloroplasts

What is the function of these organelles?

photosythesis

What is the kingdom of this organism?

Plantae

Cytoplasmic streaming

in general, not static, constant movement

Dark spot of the cell?

nucleoli

Name the organelle indicated by the pointer

amyloplast

What’s the function of this organelle?

Stores starch

Name the domain of life that this organism belongs to

Plantae

What is the round red object in the cells?

Nucleus

What are the dark spots in it?

Nucleoli

Is this a eukaryote or prokaryote? How do you know?

eukaryote, by the nucleus

What is the mode of nutrition of this organism?

autotroph

What Kingdom does this organism belong to?

Plantae

True or False: All unicellular organisms are prokaryotes

false

Equatorial plane

where the chromosomes align in metaphase

What is the structure at the pointer

Cell plate

The presence of this structure indicates that the process of __ has started

cytokinesis

What phase of division is this cell in? Name of division that occurs after this phase?

telophase and cytokinesis

What is the Domain of this organism? What kingdom? How do you know?

Domain Eukarya, Kingdom Plantae, we know this because the presence of a nucleus (eukaryote) and the cell walls are glued together (plantae)