Eukaryotic cells (CH 4.3)

Question 1

What is the PRIME feature of Eukaryotic cells?

Answer 1

-Having different compartments (Compartmentalization)

Question 2

How is Compartmentalization achieved?

Answer 2

• Combo of extensive Endomembrane System= weaves through cell interior by numerous organelles
• Organelles include membrane-bounded structures to from compartments which biochem processes can proceed together/ independently

Question 3

What are Central Vacuoles?

Answer 3

• Large membrane-bounded sac found in plants

- Stores proteins, pigments, waste materials

Question 4

What are Vesicles?

Answer 4

• Found in both animals &; plants

- Smaller sacs that store &; transport a variety of materials

Question 5

What are all Eukaryotic cells supported by?

Answer 5

-Cytoskelton= internal protein scaffold

Question 6

What kind of walls do Fungi & many protists have?

Answer 6

-Walls made out of cellulose or chitin fibers embedded in a matrix of Polysaccharides & proteins

Question 7

What is the Nucleolus?

Answer 7

• A dark-straining zone that Nuclei exhibit

- Region where extensive synthesis of ribosomal RNA takes place

Question 8

What makes up the Nuclear Envelope?

Answer 8

• The 2 phospholipid bilayer membranes
• Outer membrane is continuous w/ cytoplasm’s interior membrane system= Endoplasmic Reticulum
• Inner Surface is covered w/ network of fibers that make up Nuclear Lamina= Nuclear Lamins
• Scattered on top= Nuclear Pores

Question 9

What are Nuclear Pores?

Answer 9

• Form 50-80 nm apart at locations where the 2 membrane layers of nuclear envelope come together
• Allow ions &; small molecules to diffuse freely between nucleoplasm &; cytoplasm while controlling the passage of proteins & RNA- protein complexes

Question 10

How is transport across the pore controlled?

Answer 10

-Import of proteins that function in the nucleus & the export to the cytoplasm of RNA &; RNA protein complexes formed in the nucleus

Question 11

What is the job of the Nuclear Lamina?

Answer 11

• Gives cell nucleus it’s shape

- Involved in reconstruction/ deconstruction of the nuclear envelope that accompanies cell division

Question 12

What is Chromatin?

Answer 12

• It’s the Structure where the DNA that is divided into linear chromosomes & proteins are organized into
• The structure of chromatin effects the function of DNA
• Must be further compacted into more highly condensed state that forms X shaped chromosomes

Question 13

What must cells do BEFORE synthesizing proteins in large quantities?

Answer 13

• First construct a large # of ribosomes to carry out this synthesis
• Hundreds of copies of genes encoding ribosomal RNA are clustered together on a chormosome= faciliating ribosomal construction

Question 14

How does the cell rapidly generate large numbers of molecules needed to produce ribosomes?

Answer 14

-By transcribing RNA molecules from the cluster of hella copies of genes encoding ribosomal RNA clustered on the chromosome

Question 15

What does the DNA sequence in a cell’s nucleus do?

Answer 15

-Encodes amino acid sequence of each protein in the cell

Question 16

What is protein synthesis associated with?

Answer 16

-Large RNA-protein complexes (ribosomes) outside of nucleus

Question 17

What are Ribosomes composed of & what are they known to be?

Answer 17

• 2 subunits=Ribosomal RNA (rRNA) & proteins
• “Universal Orgnelles”= found in all cell types across all 3 domains of life
• Factories that make proteins

Question 18

How do the 2 subunits join to form a functional ribosome?

Answer 18

• Only when actively synthesizing proteins
• Requires 2 other forms of RNA= Messenger RNA (mRNA= carries coding info from DNA) & Transfer RNA (tRNA= carries amino acids)

Question 19

How may Ribosomes be found in the cell?

Answer 19

• Floating around in cystoplasm

- Associated w/ internal membranes

Question 20

A Ribosome is free, floating around in cytoplasm. What does it do?

Answer 20

-Synthesizes proteins found in cytoplasm, Nuclear Proteins, Mitochondrial Proteins & proteins found in other organelles not derived from endomembrane system

Question 21

What do Membrane Associated Ribosomes do?

Answer 21

-Synthesize membrane proteins, proteins found in endomembrane system & proteins destined for export from the cell

Question 22

What are included in the Domain or Eukarya?

Answer 22

-Fungi, protists, animals, plants

Question 23

What are the 3 kinds of specialization for Eukaryotic cells?

Answer 23

• Having different compartments to perform specialized functions
• Specialized cell types for different organisms
• Specialized cell types between different cells in one organism (each cell type will have its own composition & arrangement of organelles)

Question 24

What occurs on the different compartments for specialized functions?

Answer 24

• Compartments= membrane bound organelles
• Isolate particular specialized reactions
• Allows special conditions in each compartment bc membrane is relatively impermeable= creates efficiency
• Creates a need for transport within compartments