Eukaryotes And Prokaryotes Flashcards
Where is DNA located in eukaryotes?
In membrane-bound organelles.
Where is DNA located in prokaryotes?
In a non-enclosed nucleoid.
What shape are chromosomes in prokaryotes?
Circular.
What shape are chromosomes in eukaryotes?
Linear.
Where is extra-chromosomal DNA found in prokaryotes?
In plasmids.
Where is extra-chromosomal DNA found in eukaryotes?
In plasmids only in yeast.
How does cell division take place in prokaryotes?
By binary fission.
How does cell division take place in eukaryotes?
By mitosis/cytokinesis.
How does recombination of genetic material occur in prokaryotes?
Through conjugation, transduction and transformation.
How does recombination of genetic material occur in eukaryotes?
Through sexual reproduction - Meiosis produces haploid gametes.
Do prokaryotes have membrane-bound organelles?
No.
Do eukaryotes have membrane-bound organelles?
Yes.
What does the cell membrane of prokaryotes contain?
Hopanoids.
What does the cell membrane of eukaryotes contain?
Sterols.
What is the structure of a flagella in prokaryotes?
There are diverse structures, however there is only one protein known as flagellin.
What is the structure of a flagella in eukaryotes?
9 double and 2 single microtubules.
What is the size of a ribosome in prokaryotes?
70S (50S + 30S).
What is the size of a ribosome in eukaryotes?
80S (60S + 40S).
What is the cell wall composed of in prokaryotes?
Eubacteria = Peptidoglycan Archaea = Other polymers.
What is the cell wall composed of in eukaryotes?
Plants = Cellulose Fungi = Chitin
Where does respiration occur in prokaryotes?
Across the cell membrane.
Where does respiration occur in eukaryotes?
In the mitochondria.
Where does photosynthesis occur in prokaryotes?
In association with membranes and vesicles.
Where does photosynthesis occur in eukaryotes?
In chloroplasts.
Describe the structure of the nucleus.
- Composed of chromatin and nucleoplasm.
- Nucleolus is a dense region.
- Nuclear envelope is a double membrane which is lined by lamina and perforated by pores for exchange.
- The envelope is continuous with endoplasmic reticulum; both have ribosomes.
What two organelles does the nucleus interact with?
- Cytoskeleton.
2. Endomembrane system.
State five functions of the nucleus.
- Compartmentalisation.
- Stores genetic information in a loose and condensed form.
- It uncoils loose DNA for replication and mRNA production.
- It organises chromosomes into a condensed form before mitosis.
- Ribosome production.
Describe five features of the structure of the nuclear envelope.
- It has a double membrane and the outer membrane links to RER.
- There is perinuclear space in between.
- Ribosomes are on outer membrane.
- Pores span the envelope.
- Membrane proteins link to cytoskeleton.
State two functions of the nuclear envelope.
- It separates the nucleoplasm from the cytoplasm which is known as compartmentalisation.
- The nuclear lamina of protein filaments maintain the shape.
Pores contain a large protein complex that regulates what two things?
- Importation of proteins e.g. histones.
2. Export of mRNA and ribosome subunits.
Describe the structure of a nucleolus.
It has more than one dark region in the nucleus and is not membrane bound.
What three things does the nucleolus contain?
- Hundreds of copies of ribosomal genes which code for rRNA.
- rRNA transcripts.
- r-proteins from cytoplasm.
What is the function of the nucleolus?
Ribosome synthesis.
How does the nucleolus carry out ribosome synthesis?
rRNA + r-proteins = ribosome subunit. The subunits are then exported to the cytoplasm.
Describe the structure of a ribosome.
It is a complex of catalytic rRNA and structural protein. It may exist as a polysome.
What are the two subunits of a ribosome?
Large sub-unint (LSU) and small sub-unit (SSU).
What is a small sub-unit composed of?
One strand of rRNA and more than twenty proteins.
What is a large sub-unit composed of?
Two strands of rRNA and more than thirty proteins.
What is the purpose of a sub-unit?
They only join to translate mRNA to amino acids.
What is the function of free ribosomes?
They make proteins that function in cytosol.