Cell Organelles

Question 1

What is the cytoplasm?

Answer 1

Consists of:

-cytosol (water, K+, proteins, amino acids, lipids, and carbohydrates)
-organelles
-inclusions (insoluble, ex. glycogen granules, pigments)

Question 2

How much space does the cytosol take up within the cell?

Answer 2

55% cell volume

Question 3

What is the cytoskeleton made up of?

Answer 3

Microfilaments (actin), thick filaments (myosin), intermediate filaments (keratin), microtubules (tubulin)

Question 4

What are cilia?

Answer 4

5-10 um in length, made of microtubules that helps movement and flow

found in the trachea, fallopian tubes

Question 5

What are flagella?

Answer 5

50 um in length and helps with movement

-only found on sperm cells

Question 6

What are centrosomes?

Answer 6

Pair of centrioles at right angles, migrate to poles during mitosis

organize and move the spindle fibers in dividing cells, necessary for cell division

Question 7

Which cells do not have centrioles?

Answer 7

Red blood cells, skeletal muscle cells, cardiac muscle cells, most neurons

Question 8

What are proteasomes?

Answer 8

Hollow cylinders of proteolytic enzymes (breaks down proteins) with regulatory proteins at their ends

breaks down and recycles damaged and abnormal intracellular proteins

Question 9

What are ribosomes?

Answer 9

RNA + proteins; fixed ribosomes bound to rough endoplasmic reticulum, free ribosomes scattered in cytoplasm

site of protein synthesis

Question 10

What are mitochondria?

Answer 10

Double membrane with inner membrane folds (cristae) enclosing important metabolic enzymes

site of cellular respiration, produces 95% of the ATP required by the cell

Question 11

What are the membranous organelles?

Answer 11

Nucleus, endoplasmic reticulum, mitochondria, golgi apparatus, plastids, lysosomes

Question 12

What are the non-membranous organelles?

Answer 12

Ribosomes, centrioles, cilia, flagella, microtubules, microfilaments, and intermediate filaments

Question 13

What is the endoplasmic reticulum and what are the functions?

Answer 13

A network of membranes connected to membranous nuclear envelope

-Synthesis of proteins, carbohydrates, phospholipids, cholesterol, and steroid hormones
-Storage of TGs, glycolipids, Ca2+
-Transport
-Detox-drugs are metabolized; toxins are neutralized by enzymes

Question 14

What does the smooth endoplasmic reticulum do?

Answer 14

Synthesis of lipids, secretion of hormones, detoxification/metabolization of drugs, and large Ca2+ store, many present in the liver

Question 15

What does the rough endoplasmic reticulum do?

Answer 15

Protein synthesis, modification and folding, and manufacturing of phospholipids

Question 16

What does the golgi body do?

Answer 16

A stack of flattened membrane (cisternae) containing chambers that processes and packages proteins, stores, alters and packages secretory produces and lysosomal enzymes

packages the newly synthesized proteins and lipids from the endoplasmic reticulum

-hormones or matrix proteins are exported
-digestive enzymes are packaged into vessels to form lysosomes

Question 17

What are lysosomes?

Answer 17

Contain digestive enzymes that break things down

intracellular removal of damaged organelles or pathogens

Question 18

What are secretory vesicles?

Answer 18

Contain hormones and proteins for export, specific to the cell and then exports using exocytosis

Question 19

What are membrane renewal vesicles?

Answer 19

Vesicles that contain lipids and proteins for membrane repair

Question 20

What are peroxisomes?

Answer 20

Vesicles containing degradative enzymes

catabolism of fats and other organic compounds; catalase neutralization of toxic compounds (H2O2 hydrogen peroxide) generated in the process

Question 21

What is autolysis

Answer 21

Cell self-digestion of the cell when it is inactive or damaged

it is not planned for, rather occurs when something is wrong with the cell

occurs in unhealthy cells

Question 22

What is apoptosis?

Answer 22

Apoptosis is programmed cell death that is planned for worn out cells to be disposed of in an orderly fashion

Occurs in healthy cells

Question 23

What are the differences between apoptosis and autolysis?

Answer 23

Apoptosis is planned for while autolysis is not

autolysis results with the death of injured or diseased cells, whereas apoptosis is programmed for healthy cells at a certain point

Question 24

What is the nuclear envelope?

Answer 24

Membrane double layer of lipids that protects the cell’s DNA and regulates entry and exit into the nucleus

Question 25

What can cross through the nuclear pore?

Answer 25

Small molecules, ions, mRNA (not DNA or proteins, as they are too large to enter)

Question 26

What is a nucleus?

Answer 26

Largest organelle in the cell

Nucleoplasm containing nucleotides, enzymes, nucleoproteins, and chromatin; surrounded by a double lipid membrane (nuclear envelope)

It functions as the control center of a cell and controls metabolism, storage and information processing of genetic information; control of protein synthesis

-contains nuclear lamina: scaffolding protein network of intermediate filaments that supports shape
-consists of rDNA and protein
-larger in muscle and liver cells as they produce a lot of protein

Question 27

What is a nucleolus?

Answer 27

Site of rRNA synthesis and assembly of ribosomal subunits

Question 28

What are nuclear pores?

Answer 28

About 10% of the nuclear envelope and facilitates entry to the nucleus

allows for diffusion of small molecules and ions; active transport of large proteins

Question 29

In what form can DNA be found in the nucleus?

Answer 29

Chromatin and chromosome

Question 30

What is chromatin?

Answer 30

Uncoiled DNA which supercoils (condenses) during prophase and decondenses during telophase

Question 31

What are the 3’ and 5’ ends of DNA?

Answer 31

Corresponding to the carbon numbering of deoxyribose

Question 32

What direction does DNA polymerase join nucleotides together?

Answer 32

5’ to 3’ direction

Question 33

What does the DNA helicase do?

Answer 33

Helix enzyme unwinds the strands and disrupt the hydrogen bonds

Question 34

What does DNA Ligase do?

Answer 34

DNA ligase enzyme joins two DNA segments with covalent bonds

Question 35

What kind of membranes are present within the Golgi body?

Answer 35

Cisternae; stacks of flattened membranes containing chambers

Question 36

What kind of membranes are present within mitochondria?

Answer 36

Cristae; inner membrane folds that enclose important metabolic enzymes

Question 37

Which is the correct sequence of events when the RER delivers transport vesicles to the golgi apparatus?

Question 38

How are chromosomes formed?

Answer 38

&**