Question:

SCIENCE 9- define the following parts of a plant cell.. HELP PLEASE!?

by  |  earlier

1 LIKES UnLike

Cell wall:

Cell membrane:

Vacuole:

Nucleus:

Nucleolus:

Nuclear Membrane:

Chloroplast:

Mitochondrion:

Golgi Body:

Ribosomes:

Endoplasmic Reticulum:

Cytoplasm:

 Tags:

   Report

1 ANSWERS


  1. The cell nucleus is the most conspicuous organelle found in a eukaryotic cell. It houses the cell's chromosomes, and is the place where almost all DNA replication and RNA synthesis occur. The nucleus is spherical in shape and separated from the cytoplasm by a double membrane called the nuclear envelope. Mitochondria are self-replicating organelles that occur in various numbers, shapes, and sizes in the cytoplasm of all eukaryotic cells. As mitochondria contain their own genome that is separate and distinct from the nuclear genome of a cell, they play a critical role in generating energy in the eukaryotic cell, they give the cell energy by the process of respiration, adding oxygen to food (typicially pertaining to glucose and ATP) to release energy. Organelles that are modified chloroplasts are broadly called plastids, and are often involved in storage. Since they contain their own genome, they are thought to have once been separate organisms, which later formed a symbiotic relationship with the cells. Chloroplasts are the counter-part of the mitochondria. Instead of giving off CO2 and H2O Plants give off glucose, oxygen, 6 molecules of water (compared to 12 in respiration) this process is called photosynthesis.The endoplasmic reticulum (ER) is the transport network for molecules targeted for certain modifications and specific destinations, as compared to molecules that will float freely in the cytoplasm. The ER has two forms: the rough ER, which has ribosomes on its surface, and the smooth ER, which lacks them. Also the Golgi apparatus's ends "pinch" off and become new vacuoles in the animal cell. The ribosome is a large complex, composed of many molecules, in prokaryotes only exist floating freely in the cytosol, whereas in eukaryotes they can be found either free or bound to membranes

    Lysosomes and Peroxisomes (of the eukaryotic cell)  

    The cell could not house such destructive enzymes if they were not contained in a membrane-bound system. These organelles are often called a "suicide bag" because of their ability to detonate and destroy the cell.Centrosome (the cytoskeleton organiser)  

    The centrosome produces the microtubules of a cell - a key component of the cytoskeleton. It directs the transport through the ER and the Golgi apparatus. Centrosomes are composed of two centrioles, which separate during cell division and help in the formation of the mitotic spindle. A single centrosome is present in the animal cells. They are also found in some fungi and algae cells.  

    Vacuoles  

    Vacuoles store food and waste. Some vacuoles store extra water. They are often described as liquid filled space and are surrounded by a membrane. Some cells, most notably Amoeba, have contractile vacuoles, which are able to pump water out of the cell if there is too much water. A cell wall composed of cellulose and hemicellulose, pectin and in many cases lignin, and secreted by the protoplast on the outside of the cell membrane. This contrasts with the cell walls of fungi (which are made of chitin), and of bacteria, which are made of peptidoglycan.The cell membrane (also called the plasma membrane, plasmalemma or "phospholipid bilayer") is a selectively permeable lipid bilayer found in all cells.[1] It contains a wide variety of biological molecules, primarily proteins and lipids, which are involved in a vast array of cellular processes such as cell adhesion, ion channel conductance and cell signaling. The plasma membrane also serves as the attachment point for both the intracellular cytoskeleton and, if present, the cell wall.

    cell wall is a fairly rigid layer surrounding a cell, located external to the cell membrane, which provides the cell with structural support, protection, and acts as a filtering mechanism. The cell wall also prevents over-expansion when water enters the cell. They are found in plants, bacteria, archaea, fungi, and algae. Animals and most protists do not have cell walls.The nuclear envelope (also known as the perinuclear envelope, nuclear membrane, nucleolemma or karyotheca) is the double membrane of the nucleus that encloses genetic material in eukaryotic cells. It separates the contents of the nucleus (DNA in particular) from the cytosol.

    In cell biology, the nucleolus (plural nucleoli) is a sub-organelle of the cell nucleus, which itself is an organelle. A main function of the nucleolus is the production and assembly of ribosome components (RNA, proteins). The nucleolus is roughly spherical, and is surrounded by a layer of condensed chromatin. No membrane separates the nucleolus from the nucleoplasm.

Question Stats

Latest activity: earlier.
This question has 1 answers.

BECOME A GUIDE

Share your knowledge and help people by answering questions.