Cell Structure and Function

Functions of lysosomes?

1. Destroy old cells or organelles. 2. Digest food particles by fusing with food vacuoles.

What are the 2 main functions of the rough endoplasmic recticulum?

1. Make more membranes for vesicle formation. 2. Process and secrete proteins produced by ribosomes on RER.

What are the steps in the synthesis of a secretory protein?

1. Polypeptide is made by bound ribosomes and it goes into the cavity of the RER through a pore. 2. Short chains of sugars are linked to the polypeptide making a glycoprotein (glyco=sugar). 3. The glycoprotein is packaged in a transport vesicle. 4. The vesicle buds off from the ER membrane and travels to the Golgi Body for further processing.

Steps of functioning in the endomembrane system.

1. RER synthesizes proteins and then packages them in transport vesicles. 2. Transport vesicle from the RER travels to the Golgi body and fuses to the Golgi body. 3. Proteins are modified in the gogli body and then re-packaged in vesicles. 4. Transport vesicles from the golgi body travel through the cell. 5. Transport vesicles fuse with the cell membrane and their contents are released through exocytosis.

What are the 4 main functions of the smooth endoplasmic recticulum?

1. Synthesis of phospholipids for cell membrane use. 2. Synthesis of steroids eg. testosterone in testes, estrogen in ovaries. These organs are rich in SER 3. Detoxifies blood in the liver by processing drugs and other harmful chemicals. As cells are exposed to drugs the amount of SER and detoxifying enzymes increases. 4. Storage of Ca+ which stimulates muscle contraction.

How many membranes make up the nuclear envelope?

2

Vacuole?

A large storage vesicle. Vacuoles have numerous functions.

Organelles?

A membrane enclosed structure with a specialized function within the cell.

Lysosome?

A vesicle produced in the golgi apparatus containing lysosymes (enzymes which destroy old organelles or cells

What energy must cilia and flagella use to move?

ATP

What is the endomembrane system?

An interconnected system of membranes that works together in synthesis, transport, storage and secretion.

What is the difference between and attached versus a free ribosome?

Attached ribosomes are attached to the rough ER and they produce protein for export from the cell or protein that needs to be part of the membrane. Free ribosomes are unattached (floating in the cytoplasm). They produce proteins that are used in the cell cytoplasm.

Cilia and flagella?

Cellular projections that can move because they contain microtubles.

Structures found in plant cells but not in animal cells.

Cellulose cell wall, chloroplasts, large central vacuole, plasmodesmata.

Photosynthesis?

Chemical reaction that takes place in chloroplasts in which Carbon dioxide, water and sun's energy is converted in glucose and oxygen.

Name of two organelles that are energy transformers?

Chloroplasts and Mitochondria

Components of the nucleus?

Chromatin, nuclear pores, nucleolus, nucleoplasm, nuclear envelope.

Plasmodemata?

Connect cell wall to adjacent cell wall.

Function of nucleolus?

Contain and produce RNA.

To which membrane is the nuclear envelope attached?

Endoplasmic recticulum.

Mitochondria?

Found in both plant and animal cells. This is the site of "cellular respiration".

Microfilaments?

Give the cell shape and are involved in cell movement (eg. the movement of an amoeba.

How does matter cycle from chloroplasts to Mitochondria?

Glucose and oxygen produced in photosynthesis can them be use in cellular respiration, then carbon dioxide and water produced in cellular respiration can be used for photosynthesis.

What are some functions of the Golgi apparatus?

Golgi receives and modifies material manufactured in the ER. These may arrive in the form of protein or lipid filled vesicles. These molecules move through the Golgi from the inner to the outer face of the apparatus. Glycoproteins may be repackaged and send to the cell membrane for incorporation and phosphates many be added to molecules in the golgi.

Examples of secretory proteins that are manufactured by the RER.

Insulin, keratin, collagen, digestive enzymes.

Chromatin?

Is made up of DNA and protein wrapped around it. Chromatin exists when the cell is NOT dividing.

How does the golgi apparatus work with the ER?

It receives vesicles of molecules from the ER and refines them.

Cytoplasm?

Jelly like material in the entire region between the nucleus and the plasma membrane.

Intermediate filaments?

Keep cell shape, and keep some organelles in place.

Function of ribosomes in cell?

Make proteins (synthesize proteins)

Polysomes (polyribosomes)?

Many ribosomes all attached to the same mRNA and all making the same protein.

Which cytoskeleton fibres are the thinnest?

Microfiliments and microtubles.

Structures that make up the Cytoskeleton?

Microtubule, Intermediate filament, Microfiliment.

What type of cell in your body might contain lots of lysosomes?

Muscle cells where glycogen needs to be broken down into glucose. Also liver cells.

Chloroplast?

Organelle found in plant cells. Is sight of photosynthesis in which the sun's energy is used to make glucose.

What ENTERS the nucleus through the nuclear pores?

Proteins and nucleotides.

What material makes up all cytoskeleton fibres?

Proteins.

Microtubules?

Provide shape and support.

What is the only cell in the human body that has a flagellum?

Sperm

What is the function of the central vacuole of plant cells?

Stores water and provides support for the cell.

What are the parts of a chloroplast?

Stroma - thick fluid in chloroplast Thylakoid - interconnected sacs in the chloroplast Granum - stacks of thylakoids. They are embedded with chlorophyll.

Rough Endoplasmic Recticulum (RER)

Synthesis of membrane lipids and proteins, secretory proteins, hydrolytic enzymes, formation of transport vesicles.

What are some examples of cells in the body that have high levels of Smooth Endoplasmic Recticulum (SER).

Testes and ovaries. The liver.

Chromosome?

The Chromatin winds up tightly when the cell divides and becomes a chromosome.

Endomembrane system?

The entire interconnected membrane system of the cell which includes cell membrane, endoplasmic recticulum, nuclear membrane, membranes around organelle (eg. golgi, mitochondria etc.)

Cellular Respiration?

The process in which cells take glucose and oxygen into their mitochondria and convert this to ATP (energy), Carbon dioxide and water.

How do the reactions of photosynthesis and cellular respiration compare?

They are the opposite of each other.

What is the function of the ATP produced in cellular respiration?

To carry out cell work. eg. Synthesizing larger molecules, movement of organelles, active transport across cell membrane, etc.

Functions of Nucleus?

To contain DNA and nucleolus and as a result control cell activity via the genetic code.

In a paramecium, what is the function of the contractile vacuole?

To expel water from the cell.

What is the role of the transport vesicle?

To transport molecules to different parts of the cell or to the plasma membrane for export to take phospholipids to the cell membrane for incorporation.

What is the role of the transport vesicle in the process of secretory protein synthesis?

To transport the protein to the golgi apparatus.

What EXITS the nucleus through the nuclear pores?

mRNA, tRNA, and ribosomal subuits.

Three types of cytoskeleton fibres?

microfilaments intermediate filaments microtubles

Where in the human body are cilia found?

trachea and nose