Organelles and Cells

Question 1

What are Peripheral proteins?

Answer 1

Peripheral membrane proteins are found on the outside and inside surfaces of membranes, attached either to integral proteins or to phospholipids. Unlike integral membrane proteins, peripheral membrane proteins do not stick into the hydrophobic core of the membrane, and they tend to be more loosely attached.

Question 2

What are Integral membrane proteins

Answer 2

Integral membrane proteins are integrated into the membrane: they have at least one hydrophobic region that anchors them to the hydrophobic core of the phospholipid bilayer. Some stick only partway into the membrane, while others stretch from one side of the membrane to the other and are exposed on either side. Proteins that extend all the way across the membrane are called transmembrane proteins.

Question 3

What are carbohydrates?

Answer 3

Carbohydrates are the third major component of plasma membranes. In general, they are found on the outside surface of cells and are bound either to proteins (forming glycoproteins) or to lipids (forming glycolipids).

Question 4

What are the two subdivisions of the cytoplasm?

Answer 4

The cytoplasm of a cell can be subdivided into cytosol, a fluid, and intracellular structures known as the organelles. Cells are surrounded by a watery fluid known as the extracellular fluid.

Question 5

what is the nucleus and what does it do?

Answer 5

Nucleus: The nucleus has control of the metabolism of the cell, storage and processing, genetic information, and control of protein synthesis (the process in which the cell makes protein).

Question 6

What is the nucleus enveloped by?

Answer 6

The nucleus is enveloped by a nuclear envelope (Double membrane) as well as nucleoplasm

Question 7

What is contained within the Nucleoplasm

Answer 7

Nucleoplasm contains nucleotides, enzymes, nucleoproteins, and chromatin

Question 8

What do Microfilaments do?

Answer 8

Microfilaments act with other filaments to cause contraction

Question 9

What do intermediate filaments do?

Answer 9

Intermediate filaments strengthen the cell and maintain its shape, stabilize the positions of the organelles, and stabilize the position of the cell with respect to its surrounding cells

Question 10

What do Microtubules do?

Answer 10

Microtubules are the largest of the three filaments and aid in keeping cell shape, anchoring major organelles, assist in cell movement, and act as a monorail system to move vesicles and organelles

Question 11

what are the two types of Cilia

Answer 11

Cilia are fairly long and are divided into two types: Nonmotile and motile cilia

Question 12

What is the purpose of a nonmotile Cilia

Answer 12

Each cell has a single nonmotile cilia used for detection as a signal sensor (sensory)

Question 13

What is the purpose of motile cilia?

Answer 13

Motile cilia are found on cells lining the raspatory and reproductive tracts. These motile cilia move in whip like fashion to excrete harmful bacteria or dust without worry of carrying it in.

Question 14

What do ribosomes do?

Answer 14

Ribosomes are responsible for protein synthesis. The number of ribosomes in a particular cell may differ. For example, liver cells manufacture blood proteins and therefore have more ribosomes.

Question 15

What are the two subunits of ribosomes?

Answer 15

A functional ribosome consists of two subunits that are separate and distinct. The small ribosomal subunit ad the large ribosomal subunit. Before protein synthesis can begin, a small and large ribosomal subunit must join with a strand messenger RNA.
Protein synthesis may then begin

Question 16

What are the two types of ribosomes?

Answer 16

The two types of ribosomes are free and fixed ribosomes.

Question 17

What do fixed ribosomes do?

Answer 17

Fixed ribosomes are temporarily fixed to the ER where they are packed and modified for use within the cell.

Question 18

What are proteasomes and what do they do?

Answer 18

Proteasomes are smaller than free ribosomes and contain protein-digesting enzymes. Their job is to remove proteins from the cytoplasm.

Question 19

What does the Endoplasmic reticulum do?

Answer 19

The endoplasmic reticulum is responsible for the synthesis (creation) of proteins, lipids and carbohydrates, storing molecules or materials without affecting other cellular operations, transporting materials within the ER, and detoxification (the ER can absorb drugs and toxins and neutralize them using enzymes).

Question 20

What does the smooth endoplasmic reticulum do?

Answer 20

The smooth endoplasmic reticulum (SER) has the following functions:
 Synthesis of lipids, fatty acids, and carbohydrates
 The detoxification of drugs
 Synthesis of steroid hormones such as androgens and estrogens
 Synthesis and storage of glycogen

Question 21

What does the rough endoplasmic reticulum do?

Answer 21

The Rough endoplasmic reticulum (RER) is rough due to the fixed ribosomes on its surface. Due to these ribosomes, the RER’s main function is protein synthesis, storage, and transportation (to the Golgi apparatus). Some of these proteins will function inside the ER while other will combine with carbohydrates to form glycoproteins for the cell membrane.

Question 22

What does the Golgi Apparatus (Golgi body) do?

Answer 22

The Golgi apparatus receives newly synthesized proteins. The major functions of the Golgi body include:
 Modifying and packaging secretions, such as hormones or enzymes, for release from the cell
 Add or remove carbohydrates from proteins to change protein structure and thus, function
 Renews or modifies the plasma membrane
 Packages special enzymes within vesicles (lysosomes) for use in cytoplasm

Question 23

What are lysosomes?

Answer 23

Lysosomes are vesicles (storage sacs) produced by the Golgi body, containing digestive enzymes with the goal of cleaning up a cell.

Question 24

What are the two types of lysosomes?

Answer 24

Primary and Secondary

Question 25

What are the functions of the primary lysosome?

Answer 25

Primary lysosomes contain inactive digestive enzymes that can be activated and formed into secondary lysosomes.

Question 26

What do the secondary lysosomes do?

Answer 26

After turning into secondary lysosomes (SL), the SL absorbs unwanted material and breaks it down, turning into a transportation vesicle called an endosome which travels with the broken down material, eventually ejecting it using exocytosis.

Question 27

What does the Mitochondria do?

Answer 27

The mitochondria is the powerhouse of the Cell. The mitochondria produces energy for the cell using ATP molecules. Mitochondria contain their own DNA and ribosomes.

Question 28

What is the nucleus surrounded by?

Answer 28

The membranous nuclear envelope

Question 29

How does communication between the nucleus and the cytoplasm (and organelles in the cytoplasm) occur?

Answer 29

Chemical communications between the nucleus and the cytoplasm occur through opening in the nuclear envelope called nuclear pores, each pore having about 50 associated proteins.

Question 30

What are the contents of the nucleus? What is inside the nucleus?

Answer 30

The fluid portion of the nucleus is called the nucleoplasm. The nucleoplasm contains the nuclear matrix, a network of filaments that provide structural support and may be involved in the regulation of genetic activity.

Question 31

What are nucleoli and their functions?

Answer 31

Nucleoli are nuclear organelles that synthesize ribosomal RNA. Nucleoli are most prominent in cells that manufacture large amounts of protein such as liver, nerve, and muscle cells.