Mod. 2 Cells

Question 1

nuclear envelope

Answer 1

surrounds the nucleus, separating the nuclear material from the cell cytoplasm.

Question 2

centrioles

Answer 2

found only in animals cells, and are the attachment points for the spindle tubules during cell division. in pairs.

Question 3

cell wall

Answer 3

in plants only. a complex of cellulose microfibrils running through a matrix of complex polysaccharides providing support to the cell.`

Question 4

mitochondria

Answer 4

the site of aerobic respiration

Question 5

lysosome

Answer 5

a.k.a. suicide bags. They are membrane bound sacts that contain digestive enzymes which can be used to break down old organelles or the cell itself.

Question 6

smooth endoplasmic reticulum

Answer 6

makes and transports lipids and steroids

Question 7

nucleus

Answer 7

contains the genetic information in the form of DNA

Question 8

micro villi

Answer 8

increase the surface area of a cell where appropriate. e.g. the gut

Question 9

golgi apparatus

Answer 9

where polypeptides are packages for export. the protein is modified by the addition of a carbohydrate chain to form a glycoprotein.

Question 10

rough endoplasmic reticulum

Answer 10

a series of membrane-bound cavities that act as the intracellular transport system. they are studded with ribosomes.

Question 11

chloroplasts

Answer 11

site of photosynthesis

Question 12

nuclear pore

Answer 12

a small hole that allows genetic information to pass from the nucleus to the cytoplasm

Question 13

ribosomes

Answer 13

site of protein synthesis, where amino acids are joined together to form a polypeptide chain

Question 14

chromatin

Answer 14

DNA combined with histone proteins for efficient packing.

Question 15

cell membrane

Answer 15

controls the movement of substances in and out of the cell.

Question 16

nucleolus

Answer 16

a very dense chunk of DNA responsible for the manufacture of ribosomes.

Question 17

symbiosis theory

Answer 17

one type of prokaryote started living inside another, hence why mitochondria are the same size and shape as bacteria and have a double membrane. Mitochondria are also sensitive to antibiotics, and reproduce like bacteria, as well as having their own plasmid DNA ribosomes the same size as bacteria.

Question 18

What are the structures in a mitochondria?

Answer 18

• cristae (folds that increase the surface area of the inner membrane)
• inner membrane (studded with stalked particles)
• outer membrane
• ribosomes (contained inside the matrix, for protein synthesis)
• loops of plasmid DNA (for protein synthesis)
• intermembrane space (low pH because contains few H+ ions)
• stalked particles (ATP synthase)
• matrix (inside of inner membrane, high pH because it contains many H+ ions)

Question 19

what are the structures in a chloroplast?

Answer 19

• outer membrane
• inner membrane
• lamella (bridges between granum)
• stroma (space in the middle)
• granum (stack of thylakoids)
• thylakoids (membrane containing chlorophyl)
• ribosomes
• starch grain

Question 20

What kind of microscope is most useful in viewing organelles?

Answer 20

• light micoroscope have limited effective magnification because they have a low resolution.
• transmission electron microscopes allow the user to view clear images of the inside of a cell
• scanning electron microscopes only allow the user to see the outside of a cell because the electrons fired at the sample bounce off the outside.

Question 21

How are glycoproteins such as mucin adapted for their role in the golgi?

Answer 21

• the gene coding for the mucus protein is copied int he nucleus
• the mRNA copy of the mucin gene moves out of nucleus through the nuclear pore
• the mRNA is transported to a ribosome on the rough ER
• the ribosome uses the information on the mRNA to assemble amino acids in the correct sequence for the mucin protein
• the long chain of amino acids (polypeptide chain) is folded in the endoplasmic reticulum to form the mucin protein
• transport vesicles move the mucin protein from the ER to the golgi apparatus
• the mucin protein is slowly moved through the compartments of the golgi apparatus where the carbohydrate chains are attached.
• transport vesicles containing the finished mucin glyco-protein bud from the far end of the golgi apparatus
• the transport vesicles move along the micro tubules of the cytoskeleton to the cell surface membrane
• the membrane of the transport vesicle fuses with the cell surface membrane and the mucus is secreted from the cell.