Chapter 7: Inside The Cell

Question 1

Why are cells so small?

Answer 1

the main job of a cell is to take in raw material and get rid of waste through the cell membrane. If a cell gets too large, there is not enough surface area (membrane) to let everything pass.

Question 2

What are some characteristics of prokaryote cells?

Answer 2

bacteria and archaea, much smaller, no defined nucleus, have ribosomes, have plasma membrane (photosynthetic species have internal membranes), have organelles, and are a part of a multicellular organism.

Question 3

What are the characteristics of a eukaryote cell?

Answer 3

everything else (plants, animals, fungi, protists), have a true nucleus, are more complex and have a variety of organelles, surrounded by cell membrane, and has ribosomes. Tend to have much more extensive inner membrane systems and larger numbers of intracellular organelles than prokaryotes.

Question 4

The nucleus is

Answer 4

the command central. It holds most of the cell’s DNA. It is surrounded by the nuclear membrane/envelope which has nuclear pores that control entry and exit and its shape is maintained by nuclear lamina. Nucleolus-synthesis (ribosome production) of rRNA and assembly of ribosome subunits.

Question 5

Ribosomes are

Answer 5

the protein factories. They carry out protein synthesis via two ways. Free ribosomes = make proteins which will function in the cytosol. Bound ribosomes = make proteins which will be inserted into membranes or secreted - fed directly into the plasma retinum. (Technically not organelles)

Question 6

Cells with high rates of protein synthesis have a lot of ribosomes like

Answer 6

pancreatic cells.

Question 7

The endomembrane system is

Answer 7

composed of several different membranes (endoplasmic reticulum, golgi apparatus, lysosomes, vacuoles) and carrie out a variety of functions (proteins synthesis, transport, metabolism, synthesis of lipids, and detoxification of poisons).

Question 8

The structures of the endomembrane system are grouped together because

Answer 8

the membranes are related either directly continuous or through the transfer of vesicles.

Question 9

What regions make up the endoplasmic reticulum?

Answer 9

the rough ER (studded with ribosomes) and smooth ER (lacks ribosomes).

Question 10

What does the smooth ER do?

Answer 10

lipid processing, storage of calcium ions, and detoxification of drugs and poisons.

Question 11

What does the rough ER do?

Answer 11

proteins destined for secretion, shipped to other organelles or embedded in membrane. Ex: insulin.

Question 12

Why can you build up a tolerance to drugs and alcohol?

Answer 12

because smooth ER can expand surface area to break it down.

Question 13

The golgi apparatus

Answer 13

modifies, stores, and ships proteins (also adds a molecular tags like zip codes to proteins bound for secretion). It is made up of stacks of membranous sacs that are not physically connected but allow for products to be transported by vesicles.

Question 14

Lysosomes are in charge of

Answer 14

waste management. They are membranous sacs of enzymes that digest macromolecules. It does this through two ways, phagocytosis and autophagy.

Question 15

Phagocytosis is

Answer 15

engulfing solid particles and breaking them down.

Question 16

Autophagy is

Answer 16

recycling the cell’s own organic material (self-eating).

Question 17

The vacuoles is the

Answer 17

handyman. It performs a variety of functions like food vacuoles (formed by phagocytosis), digestion, and storage.

Question 18

Where is the central vacuole found?

Answer 18

found in plants. It stores inorganic ions, allows cells to grow large without increasing cytoplasm, and help plant remain rigid.

Question 19

Peroxisomes are

Answer 19

the detoxifer. It is the center for redox reactions that often produce H2O2 (toxic) and also contain catalase which breaks down H2O2. Also breakdown fatty acids and detoxifies alcohol and other toxic compounds.

Question 20

Mitochondria is the powerhouse of the cell, why?

Answer 20

it is the site of cellular respiration (produces energy for the cell in the form of ATP), it also contains their own DNA and ribosomes. It has a double membrane and is found in almost all eukaryotic cells.

Question 21

Chloroplasts are

Answer 21

the sugar factory. They have a double membrane, contain their own DNA and ribosomes, contain chlorophyll, and are the site for photosynthesis.

Question 22

How does transport within the cell?

Answer 22

Nuclear transport is highly regulated. Proteins are destined for the nucleus have specific amino acid sequence (zip code). Nuclear localization sequence = molecular zip code. Nuclear export sequence.

Question 23

What helps nuclear import and export?

Answer 23

importin and exportin.

Question 24

How do proteins get to their specific locations?

Answer 24

all proteins synthesis starts on free ribosomes. Proteins meant for endomembrane system or secretion are marked by a signal peptide (amino acids, ER signal sequence). Signal-recognition particle (SRP) escorts the ribosome to the ER membrane.

Question 25

What happens during cellular export?

Answer 25

proteins are secreted through exocytosis.

Question 26

What happens during cellular import?

Answer 26

large molecules are brought into the cell through endocytosis (receptor-mediated endocytosis, phagocytosis/pinocytosis). Digested by lysosomes, building blocks recycled.

Question 27

What functions does the cytoskeleton have?

Answer 27

structure (maintains cell shape, anchors cellular components) and motility (cellular movement and cellular highways).

Question 28

What are the 3 main types of fibers in the cytoskeleton?

Answer 28

microtubules, microfilaments (actin), and intermediate filaments.

Question 29

What are the functions of microfilaments?

Answer 29

muscle contraction and cell division. Made out of actin filaments.

Question 30

What are the functions of intermediate filaments?

Answer 30

anchorage of nucleus and certain other organelles and the formation of nuclear lamina. Made out of keratin proteins.

Question 31

What are the functions of microtubules?

Answer 31

cell motility (as in cilia or flagella) and chromosome movements in cell division. Made out of tubulin polymers.