Ch 3 Cells and Tissues

Describe the structure of the plasma membranes

Double helix that resembles a twisted ladder

List three functions of the plasma membranes:

1. Protects cell contents from the outside,
2. Regulates the exchange of things between inside and outside the cell,
3. Intra-cellular communication

Give the function of the following organelles: ribosome, Golgi apparatus, mitochondria, lysosomes, and Centriole

ribosome: : Ribosomes are a cell structure that makes protein. Protein is needed for many cell functions such as repairing damage or directing chemical processes, Golgi apparatus:A major function is the modifying, sorting and packaging of proteins for secretion. It is also involved in the transport of lipids around the cell, and the creation of lysosomes. The sacs or folds of the Golgi apparatus are called cisternae, mitochondria: produce the energy currency of the cell, ATP (i.e., phosphorylation of ADP), through respiration, and to regulate cellular metabolism. Lysosomes: cellular organelles that contain acid hydrolase enzymes that break down waste materials and cellular debris. Centrioles: The main function of the centriole is to help with cell division in animalcells. The centrioles help in the formation of the spindle fibers that separate the chromosomes during cell division (mitosis).

What is the function of the nucleus and nucleolus

Nucleus= to bring amino acids to the ribosomes... Nucleolus: dense region of the nuclear material that is critical in protein formation b/c it is where the cell makes the subunits that form ribosomes

Explain the difference between chromatin and chromosomes

-Scattered throughout nucleus, condenses to form chromosomes when cell divides, composed of DNA & Protein. Chromosomes- carries DNA genetic Information- condenses and coils up to form rod-like bodies-

the processes of diffusion and filtration

Diffusion is the process by which substances scatter themselves evenly throughout an available space. (does not require additional energy for this movement). Filtration: is the movement of water and solutes through a membrane as a result of a pushing on the other side.

7. Describe the functioning of the ion pup and explain the process of phagocytosis

the Ion Pump makes it possible a number of active transport mechanisms. An ion pump is an example of a protein structure in the cell membrane. It uses energy from ATP to actively move ions across cell membranes against their concentration gradients. Phagocytosis is another example of how a cell can actively move an object or substance through the plasma membrane and into the cytoplasm.

8. Define gene and genome

GENES-the genetic information contained in segments of the DNA molecules that are called genes ultimately determines the transmission and expression of inherited traits such as skin color and blood type from each generation of parents to their children. GENOME: All of the DNA in each cell of the body

9. Describe the process of transcription

: Part 1 of 2 steps process of transferring genetic info from nucleus into the cytoplasm. During transcription the double-stranded DNA molecule separates or unwinds and a type of RNA called messenger RNA (mRNA) is formed.

10. Describe the process of translation

Translation (step 2 of the 2 step process) is the synthesis of a protein by ribosomes which attach to the mRNA molecules in the cytoplasm.

11. List four stages in active cell division (mitosis) and briefly describe what occurs in each stages

a. Prophase: prophase-nuclear membrane dissolves , centrioles are present, chromosomes shorten and thicken and are visible, tetrads-(duplicated chromes) are joined by centromeres
b. metaphase : chromes line up at equatorial plate, centrioles attach spindle fibers to centromeres
c. anaphase: spindle finbers pull duplicated chromes to centrioles
d. telophase: cell membrane pinches in & nuclear membrane reforms