Lecture 1C: Eukaryotic Microbial Cells Flashcards
How do microbial eukaryotes compare to prokaryotes in terms of structure and size?
They are structurally more complex and typically larger.
What are the main groups of microbial eukaryotes? (4)
- Fungi
- algae
- protozoa
- other protists
What is the hallmark of eukaryotic cells?
A membrane-enclosed nucleus.
What are the nearly universal organelles in eukaryotic cells?
Mitochondria
Which organelle is found only in phototrophic eukaryotic cells?
Chloroplasts
Name other important eukaryotic organelles. (5)
- Golgi complex
- lysosomes
- endoplasmic reticulum
- microtubules
- microfilaments
What structures provide motility in some microbial eukaryotes? (2)
- Flagella
- cilia
Which microbial eukaryotes have a cell wall?
- Fungi
- algae
What molecules in eukaryotic cell membranes provide structural strength?
Sterols
They provide structural support in cells that lack a cell wall, such as protozoa and animal cells.
Sterols
It contains the chromosomes that control cell activities and is enclosed by a double membrane with an inner and outer layer.
Nucleus
What proteins help organize eukaryotic DNA: They pack negatively charged DNA into nucleosomes, forming chromosomes.
Histones (positively charged proteins).
It is continuous with the endoplasmic reticulum in many places.
outer nuclear membrane
What structures in the nuclear membrane allow molecular exchange?
Nuclear pores
What is the process of moving proteins and nucleic acids in and out of the nucleus called?
Nuclear transport
The site of ribosomal RNA (rRNA) synthesis.
nucleolus
Where is the nucleolus located?
Inside the nucleus
What is transported into the nucleolus for ribosome formation?
Ribosomal proteins synthesized in the cytoplasm.
How do ribosomal proteins and rRNA interact?
They combine to form the small and large subunits of ribosomes.
Where do the ribosome subunits go after leaving the nucleolus?
They are exported to the cytoplasm.
They assemble into functional ribosomes and participate in protein synthesis.
ribosome subunits in the cytoplasm
What are the main steps in eukaryotic cell division? (4)
for the genetic states; in order
→ Chromosome replication
→ Nuclear disassembly
→ Chromosome segregation
→ Nuclear reassembly in daughter cells.
How do prokaryotic and eukaryotic cells differ in their genetic states?
Prokaryotic cells are haploid, while microbial eukaryotes can be either haploid or diploid.
__ cells have one copy of each chromosome, while __ cells have two.
- Haploid
- diploid
Give an example of a microbial eukaryote that can exist in both haploid and diploid states.
Saccharomyces cerevisiae (brewer’s yeast):
- haploid (16 chromosomes)
- diploid (32 chromosomes)
A process in eukaryotic cells where the chromosome number is first doubled and then halved to ensure each daughter cell receives the correct set of chromosomes.
Mitosis
Meiotic cell division:
__ segregate into separate cells, reducing the genetic state from __ to __.
- Homologous chromosomes
- diploid
- haploid
It resembles mitosis: haploid cells divide again, forming a total of four haploid cells.
second meiotic division
What are the haploid cells produced by meiosis called? (2)
- Gametes in higher organisms (eggs and sperm)
- spores or related reproductive structures in eukaryotic microorganisms.
What organelles specialize in energy metabolism? (3)
- Mitochondria
- Hydrogenosomes
- Chloroplasts
These organelles evolved from what domain?
Bacteria
What do these organelles provide to the eukaryotic cell?
ATP
What are the two (2) sources of ATP production?
- Oxidation of organic compounds
- Light
Where does respiration occur in aerobic eukaryotes?
Mitochondria
What determines the number of mitochondria in a cell? (2)
- Cell type
- Cell size
How many membranes enclose the mitochondrion?
Two (Double membrane system)
What is the function of the outer mitochondrial membrane?
Allows passage of small molecules
What is the function of the inner mitochondrial membrane? (2)
- Regulates transport
- ATP production
What are the folded internal membranes in mitochondria called?
Cristae
What do cristae contain? (2)
- Enzymes for respiration
- ATP production
What is the function of transport proteins in mitochondria?
Regulate ATP passage
What does the matrix of the mitochondrion contain?
Citric acid cycle enzymes
What is the major metabolic pathway in mitochondria?
Citric acid cycle (Krebs cycle)
What kind of cells contain hydrogenosomes?
Anaerobic eukaryotic cells
What do hydrogenosomes lack? (2)
- Citric acid cycle enzymes
- Cristae
What type of metabolism do hydrogenosome-containing organisms use?
Fermentative metabolism
Name an organism that contains hydrogenosomes.
Trichomonas vaginalis
What is the major reaction in hydrogenosomes?
Oxidation of pyruvate
What are the end products of hydrogenosome metabolism? (4)
- H2
- CO2
- Acetate
- ATP
What happens to acetate in hydrogenosome-containing cells?
Excreted into the cytoplasm
What type of Archaea can be found in some anaerobic eukaryotes?
Methanogens
What do methanogens use (2) and produce?
Use H2, CO2 → Produce CH4 (Methane)
What is the function of mitochondria in aerobic eukaryotic cells?
Respiration
What is the function of cristae in mitochondria?
ATP production
What important enzyme is found in the stroma of chloroplasts?
RubisCO
Ribulose-1,5-bisphosphate carboxylase/oxygenase
What cycle occurs in the chloroplast stroma?
Calvin cycle
What is the function of thylakoids in chloroplasts?
ATP synthesis
What hypothesis explains the bacterial origin of mitochondria and chloroplasts?
Endosymbiotic hypothesis
What is the main evidence supporting the endosymbiotic hypothesis?
Organelles have their own genomes and ribosomes
What type of genome organization do mitochondria and chloroplasts have?
Circular DNA
What are some cytoplasmic structures found in microbial eukaryotes besides mitochondria and chloroplasts? (5)
- Endoplasmic reticulum
- Golgi complex
- lysosomes
- tubular structures
- motility structures
They provide shape and protect the cell from osmotic lysis.
Cell wall
What are common components of microbial eukaryotic cell walls? (2)
various polysaccharides and proteins
What are the two types of endoplasmic reticulum? (2)
- Rough ER
- smooth ER
- It has ribosomes attached to its surface
- Produces glycoproteins and new membrane material
Rough ER
Produces glycoproteins and new membrane material
Rough ER
Lipid synthesis and carbohydrate metabolism
Smooth ER
The structure of the Golgi complex is a stack of membrane-bound sacs called __.
cisternae
Modifies and sorts products from the ER for secretion or cellular use
Golgi complex
What is one major modification made in the Golgi complex?
Glycosylation (addition of sugar residues to proteins)
- Contain digestive enzymes to break down proteins, fats, and polysaccharides
- They degrade damaged cellular components and recycle materials for biosynthesis
- to prevent damage to cytoplasm, they compartmentalize lytic activities in membrane-enclosed compartments
Lysosomes
What two major components make up the cytoskeleton? (2)
- Microtubules
- microfilaments
What protein forms microtubules?
tubulin
They help separate chromosomes during mitosis.
microtubules
What protein forms microfilaments?
Actin
They provide structural support and enable movement within the cell.
Microfilaments
Do ER, Golgi complex, lysosomes, cytoskeleton, and motility structures contain DNA?
No
What are the two motility organelles? (2)
- Flagella
- cilia
What is the difference in movement between flagella and cilia?
- Flagella = slow
- cilia = fast
cilia:rotational,fast moving
flagella:rotary(prok);bending movement(euk)
What powers the flagella and cilia movement? (2)
- Dynein
- ATP
What is the structural arrangement of microtubules in flagella and cilia?
9+2 microtubule arrangement
