Chapter 4 -5 Flashcards
(20 cards)
What does the Endosymbiotic Theory state?
That mitochondria & chloroplasts evolved from ancient bacteria.
Why did they come up with the Endosymbiotic Theory?
Because mitochondria & chloroplasts resemble bacteria…
- same in size
- divide on their own
- have own DNA, ribosomes
What does the cytoskeleton do?
helps organize cell structure and activites
What is the cytoskeleton made up of?
a network of protein fibers
What are the 3 types of the cytoskeleton?
Microfilaments, Intermediate Filaments, Microtubules
Describe microfilaments.
Slender, composed of actin subunits
What is the function of microfilaments?
enable cells to change shape and move creates Pseudopods (false feet)
Describe Intermediate filaments.
In between size and most permanent.
has fibrous proteins/keratin
What is the structure of intermediate filaments?
to reinforce the cell/nucleus
Describe microtubules.
Hollow tubes of tubulin subunits that originate from centriole area
What are the functions of microtubules?
involved in cell shape vesicle/organelle mvmt chromosome mvmt work with kinesin motor proteins move the entire cell
What is the structure of microtubules?
9+2 arrangement
What do eukaryotic cell surfaces and junctions do?
protect, support, and join cells
interactions with env. and other cells.
What is the plant cell wall?
The structural component around the PM
Has cellulose and pectin scretions
How do cells communciate?
junctions called plasmodesmata - channels connect and allow cells to share water food, and chemical messages.
What does the Extracellular matrix consist of?
cellular secretions
- a sticky layer of polysaccharides
- protein fibers (Collagen)
What is the function of the ECM?
binds cells into tissues
protect and suppport
What do tight junctions do?
bind cells together into leakproof sheets
What do adhering junctions do?
link animal cells
What do gap junctions do?
Allow substances to flow from cell to cell
