1. Name all the double membrane bound cell organelles.
2. Name the organelles that contain its own DNA and ribosomes.
3. Define centriole in simple terms.
Answers
❥Question 1 :-
Name all the double membrane bound cell organelles.
❥ Answer :-
There are many cell organelles which are membrane-bound, The two organelles which have double membrane are the mitochondria and choloroplast.
❥ Additional Information :-
- Mitochondria, Chloroplasts, Endoplasmic Reticulum, Golgi Body, and Nucleus are Double Membrane bound Organelles
Mitochondria
Are sausage or cylindrical-shaped organelles found in cytoplasm
Are the sites of aerobic respiration (complete breakdown of glucose to release energy)
Number and size varies.
Has 2 membranes; outer membrane and inner membrane
Inner membrane forms a number of infoldings called the cristae
Cristae contains many enzymes required for forming ATP (storage form of energy inside a cell)
Fluid-filled space inside the mitochondria is called the matrix
Matrix contains a circular DNA, few RNA molecules and ribosomes (70S).
Are also called the powerhouses of the cell (because they generate energy required for the cell and store it in the form of ATP)
Are semi-autonomous (They have their own DNA and replicate on their own and can also synthesize most of its proteins)
Chloroplast
They are mainly present in the in leaf epidermal cells.
They are cylindrical-shaped organelles
They are the sites of photosynthesis
They have 2 membranes; outer and inner membrane
The fluid-filled internal space is called the stroma
The stroma contains thylakoids which contain the pigments chlorophyll and carotenoids.
The stroma also contains a circular DNA, few RNA molecules and ribosomes (70S).
❥Question 2 :-
Name the organelles that contain its own DNA and ribosomes.
❥ Answer :-
The cell organelles that posses their own DNA are Chloroplasts and Mitochondria.
Due , to presence of Own DNA and ribosomes,they can self replicate and translate proteins.
Hence, They are called as Semi Autonomous organelles.
❥ Additional Information :-
- Chloroplast is the cell organelle that performs Photosynthesis.
- Mitochondria is the cell organelle that performs cellular respiration.
- It is called as Powerhouse of the cell.
❥Question 3 :-
Define centriole in simple terms.
❥ Answer :-
The centriole is a cytoplasmic structure in most eukaryote cells. It is involved in cell division and in the formation of cilia and flagella. The main function of centrioles is to produce cilia during interphase and the aster and the spindle during cell division.
✿Q.1) Name all the double membrane bound cell organelles.
✿ Answer : Mitochondria and chloroplasts are the two organelles that are double-membrane-bound.
Characteristics of the mitochondria
➠Mitochondria are double- membrane-bound structures. The membrane of a mitochondrion is divided into the inner and outer membranes, distinctly divided into two aqueous compartments – outer and inner compartments. The outer membrane is very porous, while the inner membrane is deeply-folded.
➠These folds are known as cristae. They are the sites for ATP-generating chemical reactions. The membrane and matrix of a mitochondrion contains specific enzymes meant for aerobic respiration. They have their own DNA and ribosomes. Thus, they are able to make their own proteins. This is why they are considered as semi-autonomous organelles
Characteristics of chloroplasts
Chloroplasts are double-membrane-bound structures.
They are divided into outer and inner membranes, further divided into two distinct regions:
✒(i) Grana are stacks of flattened discs containing chlorophyll molecules. The flattened membranous sacs are called thylakoids. The thylakoids of adjacent grana are connected by membranous tubules called stroma lamellae.
✒(ii) Stroma is a homogenous mixture in which grana are embedded. It contains several enzymes that are used for the synthesis of carbohydrates and proteins. It also contains its own DNA and ribosomes and hence semi-autonomous organelle.
✿Q.2)Name the organelles that contain its own DNA and ribosomes.
✿ Answer : Mitochondria and Plastids like Chloroplast have their own DNA and ribosomes because of which they are able to synthesize some of their own proteins and replicate independent of the nucleus.
Due , to presence of Own DNA and ribosomes,they can self replicate and translate proteins.
Hence, They are called as Semi Autonomous organelles.
✿Q.3)Define centriole in simple terms.
✿ Answer : A centriole is a small structure made of microtubules which exists as part of the centrosome, which helps organize microtubules in the body.
A centriole is the main unit that creates and anchors microtubules in the cell.
Typically, a eukaryotic cell has one centriole that is at a right angle to a second centriole in the centrosome.
Microtubules extend from the each centriole, and use the centriole as an anchor for the base of each microtubule.
Each cell may have hundreds or thousands of microtubules that extend to various parts of the cell.
During normal cell functions, motor proteins attach to both the microtubules and an item to be transported.
The motor proteins crawl along the microtubules, dragging whatever substance or compartment with them.
Not all cells contain centrioles, and other methods are used for creating microtubules.