chapter 2.2 two types of cells Flashcards
The major types of cell are prokaryotic and eukaryotic. Prokaryotic and eukaryotic cells have many features in common, which is a reflection of their common evolutionary past. Compare prokaryotic and eukaryotic cells with respect to their: size, internal organisation, shape and location of chromosomes. Prokaryotes only exist as single cells. Eukaryotic cells have specialised organelles which facilitate biochemical processes. Represent the structure and describe the function of: Nucleus, nuc
What are prokaryotic cells?
characteristics
Includes bacteria cells:
- cells are small (1-10um)
- unicellular
- one circular chromosome
- chromosomes in cytoplasm
- no membrane bound organelles
- ribosomes present
- undergo binary fission
- cell wall present
- cell membrane and cytoplasm present
What are eukaryotic cells?
characteristics
*Include animal and plant cells:
- cells are larger (10-100um)
- unicellular and multicellular
- many linear chromosomes
- chromosomes in nucleus
- many different membrane bound organelles present
- ribosomes present
- undergo mitosis
- cell wall is only present in plant cells
- cell membrane and cytoplasm present**
What is the nucleus?
Contains DNA and controls all cell activity, regulates transcription of genes and directs photo synthesis.
What is the mitochondria?
*The mitochondria consists of an outer and inner membrane. The inner membrane is folded into cristae and matrix contains its own DNA.
*
The mitochondria is the site of aerobic respiration making ATP molecules that provide energy for the cell.
What is the chloroplast?
*Contain small membrane sacks which contain green chlorophyll
**Site of photosynthesis
The fluid within the chloroplast is called stroma
What is the vacuole?
Membrane-bound sacs for storage and waste removal
Contains water solution
Help plants maintain shape
What is the lysosome?
Lysosome: contain enzymes capable of breaking down all types of biological polymers. Only in animal cells.
What is the endoplasmic reticulum?
Moves materials around in cell and aids in lipid synthesis
Smooth type: lacks ribosomes
Rough type (pictured): ribosomes embedded in
surface
What is the nucleolus?
Structure in the nucleus which actually holds the chromosomes, in both plant and animals.
What is the golgi body?
Packages proteins into vesicles for movement out of the cell by exocytosis
What is the cell membrane?
Outer membrane of cell that controls movement of materials in and out of the cell
Double layer (Phospholipid Bilayer)
The membrane is selectively permeable
(only allows certain things in and out)
What is the cell wall?
Most commonly found in plant cells and bacteria.
Supports and protects cells
What is the cytoskeleton?
Internal framework of microtubules and microfibers
Important roles in supporting structure of the cell and function (moves organelles around)
In all cells!
Are prokaryotic cells older than eukaryotic cells?
Prokaryotic cell are older, where eukaryotic cells developed through endosymbiosis:
Endosymbiosis:
- Start with two independent prokaryotic cells
- One has some kind of evolutionary advantage (photosynthesis, respiration etc)
- The one with the evolutionary advantage get engulfed by the other through a process called endosymbiosis (a symbiotic relationship where one organism lives inside the other) and endocytosis (cellular process in which substances are brought into the cell)
- Creating a second membrane around the outside forming eukaryotic cells which are membrane bound.
Evidence is the double membrane e.g. mitochondria and chloroplast which have double membrane
They also have traces of their own DNA, only way they could have their own DNA is if it was its own cell originally
Compare plant and animal cells
**characteristics: **
size: animals are generally smaller(10-30um) than plants (10-100um)
cell wall: all plants have a cell wall (made of cellulose) but animals do not
shape: plant cells tend to be more rigid and regular in shape
chloroplasts: found in some types of plant cells but not in animal cells
vacuoles: tend to be larger, fewer in number and permeant in plant cells. smaller, more numerous and temporary in animal cells.
Lysosomes(contain enzymes which break down materials): Found in animal cells but generally not in plant cells.
Cell membrane: animal cell membranes include cholesterol but plant cell membranes do not
miotic division: mitotic division in animal cells but not in plants cells involves a pair of tiny structures called centrioles.
