Eukaryotic Cell Membrane Structure

What is the structure and what components are found in the

eukaryotic cell membrane?

Cilia, Cytoskeleton, Flagella, Ribosomes, Chloroplasts, Smooth and Rough ER, Golgi Apparatus, Lysosome, Mitochondria, Nucleus, Peroxisome

How does eukaryotic cell membrane structure differ from that of prokaryotes?

While both eukaryotic and prokaryotic cells share a basic lipid bilayer plasma membrane

• eukaryotic cell membranes contain sterols (such as cholesterol) to help maintain stability, whereas most prokaryotic cell membranes lack sterols

What sterol is found in mammalian cell membranes?

Cholesterol

What sterol is found in fungal cell membranes?

Ergosterol

What sterol is found in Mycoplasma (a prokaryote) cell membranes?

Cholesterol

How is transport across the cell membrane achieved in eukaryotes?

Active Transport and Facilitated Diffusion (aquaporins)

What is endocytosis?

Endocytosis is a cellular process where a cell internalizes external materials by engulfing them with its plasma membrane.

What are the two types of endocytosis?

Pinocytosis: receptor mediated; small molecules/ligands

Phagocytosis: phagocytes/some protozoa; large particles

describe the steps in pinocytosis

1. Cells take in liquids; Endosome

2. Endosome fusion with lysosomes/digestive enzymes forming a endolysosome

3. Exocytosis

describe the steps in phagocytosis

1. cells engulf particulate material such as bacteria; phagosome formed

2. Fusion with lysosomes forming a phagolysosome

3. Exocytosis

In what eukaryotic cells do each type of endocytosis occur?

Pinocytosis: Virtually all eukaryotic cells to maintain homeostasis and High activity areas: Especially prominent in cells lining organs involved in absorption and fluid turnover

Phagocytosis: Professional phagocytes in multicellular animals and Free-living single-celled eukaryotes

• macrophages, neutrophils, and dendritic cells

• Protists and amoebas

What is exocytosis?

Fusion of internal vesicle with cell membrane expelling the contents

describe the structures, components, location, and

functions for microtubules

Tubulin and Mitotic spindles

Movement of organelles

Flagella, cilia

describe the structures, components, location, and

functions for actin filaments

Cell membrane

Rapid assembly/disassembly; pull on the membrane

• cytoplasmic streaming, pseudopods

describe the structures, components, location, and

functions for intermediate fibers.

Scaffold to strengthen the cell

once made they dont change

What is the structure and composition of eukaryotic flagella and cilia?

Forms from a 9+3 arrangement

Then forms 9 + 2 arrangement of microtubles with a central pair

How does the movement of eukaryotic flagella differ from that of prokaryotes?

Flexible in a lashing motion

Dyenins cause the bending/lashing

What is the structure of the nucleus?

Double phospholipid bilayer (selectively permeable)

Nuclear envelope with pores

Nucleolus

Nucleoplasm

Chromosome

What is the difference between the nucleolus and the nucleoplasm?

Nucleolus: contains RNA genes

Nucleoplasm: contains genes encoding proteins + small RNA mols

What is the structure of the eukaryotic chromosome and how does it differ from that of prokaryotes?

Huge and there are multiple

Linear

Contains Histones: organize chromes

Mitosis

Meiosis

What is the process of mitosis used for?

growth, tissue repair, and asexual reproduction in eukaryotic organisms.

Chromosome number maintained in daughter cells

Its main goal is to generate two genetically identical daughter cells

What is meiosis used for?

The process of meiosis is used exclusively for sexual reproduction.

Its primary purpose is to produce gametes (sex cells, like sperm and eggs) with exactly half the number of chromosomes as the parent cell.

Haploid daughter cells

Are eukaryotic nuclei haploid or diploid?

Can be haploid or diploid depending on the cell

Diploid: two sets of chromosomes

Haploid: singular set of chromosomes

What is the structure of mitochondria?

Inner membrane

Inner membrane space

Outer membrane

Where does the citric acid cycle take place?

the mitochondrial matrix of eukaryotic cells.

The mitochondrial matrix is the fluid-filled, innermost space enclosed by the inner mitochondrial membrane.

Where are the components of the electron transport chain located?

Inside the Crista

What are the characteristics of the mitochondrial chromosome and ribosomes?

They are 70s

Closed, circular, double stranded DNA mols

What is the structure of chloroplasts?

Thykaloid Membrane

Outer membrane

Inner membrane

Thykaloid disc

Stroma

Granum: stack thylakoids

What are chloroplasts used for?

Photosynthesis in plant cells

What are the characteristics of the chloroplast chromosome

and ribosomes?

70S

Closed, circular, double stranded DNA

binary fission

What is the structure and function of the rough endoplasmic reticulum (RER)?

Site of most protein synthesis

Where is the RER located in the cell?

Cytoplasm next to the nucleus

What is the structure of the ribosomes associated with the RER?

80S= 60S+40S

Bigger than prokaryote

Proteins that need further modification are transported to which organelle

Golgi Apparatus

How is this transport accomplished?

Budding vesicle

Migrating transport vesicle

Fusion of vesicle with golgi

What is the function of the smooth endoplasmic reticulum?

Lipid synthesis and degradation

Calcium ion storage

Lipids that need further modification are transported to which organelle?

Golgi apparatus

What is the function of the Golgi apparatus

Protein modification and sorting

Also lipids

What are lysosomes and what do they contain?

destruct phagocytized material and cellular debris

Contain degrative hydrolytic enzymes

What are peroxisomes and what do they contain

Degrade lipids/toxic chemicals

Contain oxidizing agents (hydrogen peroxide)