Animalscaretips
chapter 7-eukaryotic cell structure and function
| A | B |
|---|---|
| ribosomes | small bumps located on the endoplasmic reticulum |
| vacuole | provides temporary storage of food, enzymes and waste products |
| cell wall | firm, protective structure that gives the cell its shape in plants, fungi, most bacteria and some protists |
- What is the endoplasmic reticulum composed of?
- What are the sacs in the endoplasmic reticulum?
- Where is the rough endoplasmic reticulum located in a cell?
- How is the endoplasmic reticulum formed?
- What proteins are made in the rough ER?
- What does a rough ER look like?
- What is the smooth ER function?
- What are cisternae in ER?
- Why are ribosomes on the rough ER?
- What is smooth and rough endoplasmic reticulum?
- How does the smooth ER make lipids?
- What does endoplasmic reticulum look like?
- How does the endoplasmic reticulum work?
- Do all proteins go to the endoplasmic reticulum?
- Why does rough endoplasmic reticulum appear rough under a microscope?
- Why does RER appear rough?
- How does the rough endoplasmic reticulum produce proteins?
What is the endoplasmic reticulum composed of?
The ER consists of the nuclear envelope and the peripheral ER, which includes smooth tubules and rough sheets. While the ER is defined as an interconnected network with a continuous membrane, the different structures that make up the ER perform very diverse and specialized functions within the cell.
What are the sacs in the endoplasmic reticulum?
The endoplasmic reticulum is found in most eukaryotic cells and forms an interconnected network of flattened, membrane-enclosed sacs known as cisternae (in the RER), and tubular structures in the SER. The membranes of the ER are continuous with the outer nuclear membrane.
Where is the rough endoplasmic reticulum located in a cell?
Rough ER lies immediately adjacent to the cell nucleus, and its membrane is continuous with the outer membrane of the nuclear envelope. The ribosomes on rough ER specialize in the synthesis of proteins that possess a signal sequence that directs them specifically to the ER for processing.
How is the endoplasmic reticulum formed?
We have established an in vitro system for the formation of the endoplasmic reticulum (ER). Starting from small membrane vesicles prepared from Xenopus laevis eggs, an elaborate network of membrane tubules is formed in the presence of cytosol. In the absence of cytosol, the vesicles only fuse to form large spheres.
What proteins are made in the rough ER?
Proteins synthesized by the rough ER include the prominent milk protein casein, and whey proteins. These proteins are packaged into secretory vesicles or large micelles and travel through the Golgi network before fusing with the plasma membrane, releasing their contents into milk ducts.
What does a rough ER look like?
Rough ER looks like sheets or disks of bumpy membranes while smooth ER looks more like tubes. Rough ER is called rough because it has ribosomes attached to its surface. The double membranes of smooth and rough ER form sacs called cisternae. Protein molecules are synthesized and collected in the cisternal space/lumen.
What is the smooth ER function?
smooth endoplasmic reticulum (SER), meshwork of fine disklike tubular membrane vesicles, part of a continuous membrane organelle within the cytoplasm of eukaryotic cells, that is involved in the synthesis and storage of lipids, including cholesterol and phospholipids, which are used in the production of new cellular ...
What are cisternae in ER?
A cisterna (plural: cisternae) are all of the membrane-bound sacs that could be found in both the Golgi apparatus and in the Endoplasmic Reticulum. Cisterna are an integral part of the packaging and modification processes of proteins occurring in the Golgi.
Why are ribosomes on the rough ER?
Endoplasmic reticulum is a network of membranes inside a cell through which proteins and other molecules move. ... When proteins are destined to be part of the cell membrane or exported from the cell, the ribosomes assembling them attach to the endoplasmic reticulum, giving it a rough appearance.
What is smooth and rough endoplasmic reticulum?
The main difference between these two terminologies is that the Smooth Endoplasmic Reticulum is known for stocking the lipids and proteins. It is not bounded by ribosomes. Whereas, the Rough Endoplasmic Reticulum is bounded by the ribosomes and also stores proteins.
How does the smooth ER make lipids?
The smooth endoplasmic reticulum plays a major role in synthesizing lipids by means of enzymes embedded in these smooth membranes. ... In the reproductive organs, smooth ER in the cells produces the steroid hormones testosterone and estrogen.
What does endoplasmic reticulum look like?
The endoplasmic reticulum looks like a system with membranes that form cavities, flat cisterns and non-lamellar, round structures.
How does the endoplasmic reticulum work?
Endoplasmic reticulum is a network of membranes inside a cell through which proteins and other molecules move. Proteins are assembled at organelles called ribosomes. ... Smooth endoplasmic reticulum lacks ribosomes and helps synthesize and concentrate various substances needed by the cell.
Do all proteins go to the endoplasmic reticulum?
In addition, a major portion of the cell's protein synthesis occurs on the cytosolic surface of the ER: all proteins destined for secretion and all proteins destined for the ER itself, the Golgi apparatus, the lysosomes, the endosomes, and the plasma membrane are first imported into the ER from the cytosol.
Why does rough endoplasmic reticulum appear rough under a microscope?
Rough Endoplasmic reticulum looks rough when observed under the microscope as it has presence of ribosomes on its outer surface which help it in the protein synthesis... Hope this helps!
Why does RER appear rough?
Rough Endoplasmic Reticulum (RER) appears rough because of the presence of ribosomes on it. Ribosomes are sites for biological protein synthesis. ... Polyribosomes are aggregation of several ribosomes held together by a string of mRNA.
How does the rough endoplasmic reticulum produce proteins?
The rough endoplasmic reticulum (rough ER) gets its name from the bumpy ribosomes attached to its cytoplasmic surface. As these ribosomes make proteins, they feed the newly forming protein chains into the lumen. Some are transferred fully into the ER and float inside, while others are anchored in the membrane.
