Bio Midterm 2

What is in the SAR clade?

Brown algae and dinoflagellates

What’re the 4 domains in Eukarya? (And 2 domains in Bacteria and Archaea?)

Domain Bacteria and domain Archaea

Eukarya: Animals, plants, fungi, protists

What are the differences between prokaryotic and eukaryotic?

Prokaryotic: Very small, no organelles, (e.g. mitochondria, chloroplasts, etc.) and no nucleus (Genome just swims around!) UNICELLULAR

*Archaea and bacteria are in the same sister group!

Eukaryotic: Large, organelles, and a nucleus/nucleic membrane. UNICELLULAR OR MULTICELLULAR

What defines viruses?

ACELLULAR LIFE - compared to cellular life (Bacteria, Eukarya, etc.)

Viruses have NO: Cells, homeostasis, organs, or organ like structures!

Made of nucleic acid coated in capsid and protein, they invade hosts to replicate themselves using their nucleic acids

What is in the Unikonta clade?

Animals, fungi, slime molds, and amoebas!

What is in the archaeplastidia clade?

Plants, red algae, green algae!

What are prions?

A misfolded (selfish) protein that replicates itself by misfolding others it bumps into! Another case of non-life

e.g. mad cow disease

Do PRIONS have nucleic acids, cell membranes, or membrane bound organelles?

They have none of these!

Do VIRUSES have nucleic acid, cell membranes, or membrane bound organelles?

They have NUCLEIC ACID only!

Do PROKARYOTES have nucleic acid, cell membranes, or membrane bound organelles?

They have nucleic acid and cell membranes, but NOT organs

do EUKARYOTES have nucleic acid, cell membranes or membrane bound organelles?

They have ALL 3!

How are viruses NOT life?

They have no:
homeostasis, 

What do chloroplasts do?

Photosynthesis!!

What do mitochondria do?

Aerobic respiration!

What is a ‘bacteriophage?’

A bacteria attacking virus

Where do prokaryotes land in the ‘story of earth’?

They are the ANCESTORS of all living things! First life on earth, 3.5 billion years ago

story of earth - prokaryotes, 3.5 bya

cambrian explosion 1 bya

0.5 plants and fungi bya

What’re the attributes of a prokaryotic cell?

Cell wall and capsule - protects the cell membrane

Fimbrae - used to adhere to other cells

flagella - used to move around

Where are prokaryotic genomes?

In a single CHROMOSOME, and rings of chromatids called PLASMIDS

(All just floating around)

How do prokaryotic cells eat?

They use aerobic and photosynthetic fueling, can be both hetero/auto trophs

Difference between gram POSITIVE bacter and gram NEGATIVE bacteria

Positive have a CELL WALL + plasma membrane (PEPTIDOGLYCAN LAYER, e.g. werewolf layer…)

compare to negative’s OUTERmembrane + plasma membrane

What does gram negative and gram positive affect in bacteria?

Antibiotic effectiveness depends on negative or positive - e.g. penicillin only works on gram-positive bacteria (explodes bacteria wall!)

How are Archaea different to bacteria?

Ecologically VERY different - archaea can handle crazy environments! (High temperature, salt levels, acidity, etc.)

Archaea DONT have peptidoglycan walls!

And they have incredible diversity

What environment conditions help bacteria grow?

warm and moist

What is symbiosis, and what are it’s three types?

Interaction between two organisms living close together -

Parasitism - when one hurts the other (stomach ulcer)

Commensalism - When they coexist and no one is harmed (e.g. gut bacteria)

Mutualism - Both parties benefit! (e.g. clown fish + sea anemones)

What does pathogenic mean?

Disease causing (Can be prokaryotes)

What does heterotroph and autotroph mean?

Where an organism gets it’s energy and carbon

Heterotroph is from it’s outside environment (Us eating cows)

Autotroph is from itself (Photosynthesis)

What’s closer to eukaryotes - bacteria or archaea?

Archaea!

bacteria and archaea are from the same common ancestor, and eukarya stems from archaea

How did prokaryotes help reshape the chemistry of early earth?

photosynthesis by Cyanobacteria (colonial bacteria) released massive amounts of oxygen into the atmosphere!

What holds all the cells together in plants, animals, bacteria and fungi?

Plants - cellulose

Animals - collagen

Fungi - Chitin

Bacteria - peptidoglycan

Virus - capsid layer

Are bacteria and Archaea unicellular?

YESS

What is endosymbiosis?

CREATED ORGANS IN CELLS.

Endosymbiosis is a symbiotic relationship where one organism lives inside another, leading to a mutually beneficial, and sometimes permanent, partnership

What’s the ancestor of all living things?

Prokaryotes

Commensalism vs mutualism

commensalism is coexisting, mutualism is when both benefit!

What’re plastids?

organelles that evolved by multiple endosymbiosis events!

Many lineages in eukarya evolved this way

What’s the origin/purpose of the nucleus in a eukaryote?

It’s origin is unknown, and its suggested purpose is to protect chromatin (DNA) from harmful mitochondria byproducts

How’re protists diverse?

They’re diverse in ecology and diet, as they can be both hetero and autotrophs! (Some are both - mixotrophs!)

What’re the four groups of eukaryotic ancestors?

Archaeplastida - plants

Unikonta - fungi and animals

SAR Clade

Excavata

What’re some characteristics of Archaeplastida?

(Encompasses PLANTS) often autotrophic and multicellular

also green and red algae!

What’re some characteristics of Unikonta?

Encompasses fungi and animals, and includes plasmodial slime blobs and ameobas!

What’re some characteristics of the SAR clade?

usually microscopic, heterotrophic, and mobile - often have rhizopods!

majority are unicellular, but some are multicellular!

Brown Algae, dinoflagellates, etc.

What makes animals different from plants?

Animals don’t have chloroplasts OR cell walls, they also have collagen instead of cellulose, and all animals are heterotrophs

What makes animals different than bacteria?

Animals have nucleuses and membrane bound organelles, are all heterotrophic, and has no cell wall! (Bacteria have cell walls) They have collagen instead, and bacteria has peptidoglycan

Do eukaryotes have cell walls?

NO! they have collagen instead :)

What is the dominant phase in the animal life cycle?

Animals have a life cycle dominated by the diploid phase! 1, 2, 3, 4 phase

What’re the four main components of the life cycle?

Zygote, diploid growth (mitosis), meiosis, haploid (Gametes)

When did animals first appear?

0.5 billion years ago in the Cambrian explosion

How’re animals divided into groups?

By the amount of true tissues and body symmetry

How many types of true tissue are there?

Ectoderm - skin

mesoderm - muscle layer

endoderm - digestive tract

Difference of sponges and cnidarians? (Jellyfish)

Sponges have no symmetry and no tissue, while cnidarians have radial symmetry and TWO tissues!

Difference of cnidarians and chordates, echinoderms, worms, arthropods, molluscs, etc.

Cnidarians have radial symmetry and TWO tissues, while

everything else has bilateral symmetry and THREE tissues!

What’re the characteristics of a sponge?

Simplest animals, multicellular but NO tissues!

immobile during adult/diploid phase

filter feeders

hermaphrodictic - makes both sperm AND eggs

Can reproduce asexually sometimes

What’re some characteristics of cnidarians?

Radially symmetrical, and has TWO tissues

predatory, and mobile during adult/diploid phase

sometimes reproduces asexually

(Epidermis and gastrodermis)

What’re the 4 groups we’re focusing on in Bilaterians? (3 tissue, bilaterally symmetrical clade)

Majority of life on the planet!

Molluscs, arthropods, echinoderms, and chordates

Characteristics of Molluscs?

Soft-bodied, but often shelled
• Some sessile (immobile)
• Some mobile but (mostly) slow
• Mostly marine & freshwater
• Herbivores, carnivores, detritivores (Dead and decaying matter)

SNAILS, cuttlefish, squids, octopi, and cephalopods…

What’re cephalopods?

Very, very old molluscs that are also fast predators

Characteristics of arthropods?

insects, crustaceans, lobsters, scorpions, spiders, etc. 

FIRST ANIMALS TO ADAPT TO TERRESTRIAL LIFE (And first flying animals! (insects))

Segmented, and shed exoskeletons during growth

exoskeletons are great for water retention, protection, sensory, claws, etc. 

What does hexapod mean?

6 legs

Characteristics of echinoderms?

Starfish, urchins, sea cucumbers, etc.

Known for tube feet, soft bodied, though sometimes supported by a mineralized endoskeleton…

ALWAYS BILATERALLY SYMMETRICAL

(Because divided in 5, and 5 is not radial…)

Chordate characteristics?

NOTOCHORD! In all chordates, is a semi-rigid line along spine (Might dissolve after being a baby)

invertebrate vs. vertebrate?

No spine, yes spine

(Chordates are the only group here WITH vertebrates, and even then it’s a subcategory.)

What’s a tetrapod?

In the chordate group, it’s animals with 4 legs now! starts with amphibians to mammals

What’s an amniote?

Another chordate subgroup, it’s animals with shelled eggs. (reptiles and mammals)

What’s a mammal?

An amniote with hair and milk production

Are fungi more closely related to plants or animals?

Animals!

What’re the defining features of fungi?

Fungi can be multicellular OR unicellular
Cell walls contain CHITIN which provides structural support
The majority of biomass of a multicellular fungus is referred to as the mycelium (e.g. the ‘body’ of growing mold is the mycelium)
ALL are heterotrophs, feeding by absorption

Many can reproduce asexually!

What’s the dominant stage of a fungi life cycle?

Normally HAPLOID dominant with the exception of a small diploid stage during sexual reproduction, which is then followed by HAPLOID SPORES!

What’s the stage of what we normally see in fungi?

The mushroom we see is the reproductive stage! (Makes sexual spores)

e.g. gills, pores, teeth, etc.

What’re the steps of a fungi life cycle?

1, 3, 4, ?

Zygote, meiosis, haploid phase, heterokaryotic phase! (NOTICE: no mitosis…)

(There’s separate cells with separate nuclei, which then morph but nuclei stay separated in Heterokaryotic phase - these can replicate.) 

n /  n + n /  n2

Do fungi have male and female?

NO! They have mating types, which allows for a lot more mating possibilities - like if there were a hundred genders and they all mated with different kinds and amounts.

What does sexual reproduction look like in fungi?

begins with a heterokaryotic stage, and is followed by a short-lived unicellular diploid stage, immediately followed THEN by meiosis

what is Mycorrhizae?

symbiotic associations between plant roots and fungi - it’s mutualistic because the fungi helps the tree absorb nutrients and water, and the tree protects the fungi

what are lichens?

Lichens is a mutualistic association between a fungus and a photosynthetic partner, usually an alga or cyanobacterium. The fungus provides a protective structure and absorbs water and minerals, while the photosynthetic partner produces food (sugars) through photosynthesis

What’s a tunicate?

The ugly water tubes without spines…

What’re the 5 main groups of fungi?

Chytrids, Zygomycetes (zygote fungi), glomeromycetes, ascomycetes (Sac fungi), and basidomycetes (club fungi)

Characteristic of club fungi?

Their spores are on tiny clubs (basidiums)!

Characteristic of sac fungi?

We call acomycetes sac fungi because they keep their spores in a little sac (ascus)

Glomomycetes characteristics?

they’re ancient and ASEXUAL!

glomeris translates to ball shaped

found in 80% of land plants, kind of look like little trees!

Zygote characteristics?

‘Zygote’ is just a reference to how their sexual spores are formed → fusion of two mating hyphae
Release asexual sporangiospores in the air to contaminate

BREAD MOLD!

Chytrid characteristics?

In marine habitats, these are the only flagellated spores!

What’re some roles and relationships of fungi?

Decomposers - saprotrophs (eat dead things)

Predators - fungi trapping nematodes

Symbioses

What plant groups still depend on aquatic reproduction?

Nonvascular seedless plants AND seedless vascular plants! (Mosses, ferns, etc.)

What are lycophytes?

club mosses! They’re seedless vascular

What are monilophytes?

Ferns and such, seedless vascular as well!

What are gymnosperms and angiosperms?

Gymnosperms are pinecones and such, like trees, and angiosperms are flowers! These are seed plants

What are the key features of plants?

1. Multicellular, autotrophic and eukaryotic

2. Alternation of generations

3. dependent embyros (Need food and such, like endosperm)

4. CHLOROPLASTS and CELLULOSE

What’s a typical plant life cycle?

1. Zygote, which goes through mitosis to make a sporophyte, (Plant) then meiosis makes spores which THEMSELVES go through mitosis to make gametophytes! (usually gendered structures) the gametophyte then fertilizes and makes the zygote

Are gametophytes and sporophytes haploid or diploid?

Sporophytes are diploid and gametophytes are haploid, both multicellular!

difference between gymnosperms and angiosperms?

Gymnosperms are NAKED seeds,

angiosperms are ENCASED seeds

Nonvascular seedless group characteristics  (mosses)

Gametophyte dominate life cycles, and they have no roots - they have rhizoids!

sporophyte is the little penis capsules

What does a moss lifecycle look like?

1, 2, 3, 2, 4

(Zygote, mitosis, meiosis, mitosis and haploid)

homospores

What are some plant adaptions to terrestrial life?

1. maintaining moisture with wax cuticles and vascular tissues

2. obtaining resources from AIR and DIRT

3. LIGNIN, which supports the plant body. Makes wood for trees and shit

Where do ferns produce spores?

FERNS HAVE SORI’s - that’s their sperm…

What does a fern life cycle look like?

1, 2, 3, 2, 4

They can produce both sperm AND egg - homospores

What are the three parts of a seed?

Seed coat (2n)

Food supply/endosperm (3n)

embryo (2n)

Homospory vs Heterospory

Homospory is same sizes in the spores which make gametophytes, and heterospory is when the spores have different sizes

Megasporangia vs. Microsporangia

MEGAsporangia produce megaspores that make FEMALE gametophytes

MICROsporangia produce microspores that make MALE gametophytes

Where do microspores develop? Megaspores?

Microspores develop into pollen which contain male gametophytes, while megaspores develop into female gametophytes that remain in the ovule

Both are haploid

Summarize gymnosperm fertilization

Gen 1 - sporophyte makes ovule

Gen 2 - gametophyte makes egg

Gen 3 - fertilized egg turns into embryo (The NEW sporophyte)

What’re the four rings of a flower? (Defining feature!)

Carpel (Has the ovules)

Stamen (Has anthers which make the sperm)

Petals

Sepals

What’s another defining feature of flowers?

FRUIT! (Ovule becomes the fruit!)