M3: Cell Structure

Question 1

Plant cells consist of a box-like cell wall surrounding a mass of _

Answer 1

protoplasm

Question 2

The protoplasm contains organelles, such as

Answer 2

Nuclei
Mitochondria
Chloroplasts

Question 3

The physical framework within which a plant’s metabolism occurs.

Answer 3

Cells

Question 4

They regulate the passage of molecules into and out of cells and organelles.

They divide the cell into numerous compartments, each with its own specialized function.

They act as surfaces that hold enzymes.

Answer 4

Membranes

Question 5

Biological membranes are composed of_ and a _ bilayer.

Answer 5

proteins

phospholipid bilayer

Question 6

_ proteins are at least partially immersed in the lipid bilayer.

Answer 6

Intrinsic

Question 7

_ proteins are located outside the membrane.

Answer 7

Extrinsic

Question 8

• In the fluid _ _, some proteins diffuse laterally and others are bound to adjacent proteins.
• Oligosaccharides can be bound to intrinsic proteins, converting them into _.

Answer 8

mosaic membrane

glycoproteins

Question 9

• _ —additional membrane molecules can be incorporated into existing membranes

Answer 9

Growth

Question 10

Transport of material
• _—membrane “bubbles” that can carry materials with the cytoplasm

_ and _

Answer 10

Vesicles

Exocytosis and endocytosis

Question 11

• _ -all biological membranes are selectively permeable.
Allows for compartmentalization

Answer 11

Permeability

Question 12

• _ -constantly changing in response to age and environment

Answer 12

Dynamic

Question 13

● _ are more permeable to hydrophobic substances than anything carrying an electric charge.

Answer 13

Membranes

Question 14

● Movement of charged substances is assisted by large intrinsic proteins that span the membrane.

Answer 14

Facilitated diffusion

Question 15

● Molecular pumps bind to a molecule on one side of the membrane, change shape, and release the molecule on the other side—requires energy.

Answer 15

Active transport

Question 16

Structurally more simple than eukaryotic cells.

They are found in domains Bacteria and Archaea.

Answer 16

Prokaryotic

Question 17

Contain a membrane bound nucleus and organelles.
They are found in plants, animals, fungi, and protists.

Answer 17

Eukaryotic

Question 18

A mass of proteins, lipids, nucleic acids, and water within a cell Includes organelles but not the cell wall

Answer 18

Protoplasm

Question 19

The selectively permeable membrane that covers the protoplasm

Located inside of the cell wall

Answer 19

Plasma membrane

Question 20

The _ stores the organism’s genetic information.

Is surrounded by the nuclear envelope.

Answer 20

nucleus

Question 21

Nucleus

○ Composed of two membranes:

○ Contains small holes called _ _

Answer 21

outer and inner membranes.

nuclear pores.

Question 22

The nucleus holds _ ,
consisting of DNA, enzymes, histone proteins, RNAs, and water.
○ Contains , where ribosomes are made and partially assembled.
○ Occupies up to% of the cell volume.

Answer 22

nucleoplasm

nucleoli

50

Question 23

The _ _ has a single membrane, the tonoplast.

Answer 23

central vacuole

Question 24

○ Stores water, salts, crystals, starch, protein bodies, and other granules.
○ Critical for cell enlargement.
○ Recycles _ by taking in
old, impaired organelles and using digestive enzymes to break them down.

Answer 24

central vacuole

monomers

Question 25

the site of cellular respiration.

Answer 25

mitochondria

Question 26

Also Have an outer and inner membrane. ○ Inner membrane folds forming cristae increasing surface area. ○ Have their own circular DNA resembling that of prokaryotes. ○ Can divide or enlarge as needed.

Answer 26

mitochondria

Question 27

_ have an inner and outer membrane and an inner fluid called the _.

Answer 27

Plastids stroma

Question 28

○ Includes chloroplasts. ○ Diverse metabolisms take place in other plastid classes. ○ Contain their own circular DNA resembling that of prokaryotes.

Answer 28

Plastids

Question 29

● _ are responsible for photosynthesis and contain _.

Answer 29

Chloroplasts chlorophyll

Question 30

○ Membrane sheets called _ project into the stroma. ○ They can form stacks of vesicles called _.

Answer 30

thylakoids grana

Question 31

● Starch-storing plastids. ● Occur in nonphotosynth etic areas of the plant.

Answer 31

Amyloplasts

Question 32

3 other plastids

Answer 32

chromoplasts leucoplasts phytoferritin

Question 33

1. _- store bright lipid pigments found in some fruits and flowers. 2. _- large, unpigmented plastids involved in fat and lipid synthesis. 3.- a plant protein attached to stored iron that is almost exclusively stored in plastids.

Answer 33

Chromoplasts Leucoplasts Phytoferritin

Question 34

● _ are the site of protein synthesis. ○ Occur in the cytoplasm. ○ Are aggregates of 3 molecules of ribosomal RNA and ~50 types of protein. ○ Bound together by the messenger RNA, forming a cluster called a _.

Answer 34

Ribosomes polysome

Question 35

● _ _ is a system of narrow tubes and sheets of membrane within the cytoplasm. ● Important in both manufacture and transport of molecules. ● Two forms: ○ _ (covered with ribosomes) ○ _ (involved in lipid synthesis and membrane assembly)

Answer 35

Endoplasmic reticulum (ER) Rough Smooth

Question 36

_ are stacks of thin vesicles held together in an array that processes materials to be secreted. ○ Have a forming face where ER vesicles accumulate. ○ And a maturing face where vesicles are released after the contents are processed.

Answer 36

Dictyosomes

Question 37

_ _consists of all the cell membranes except for the inner membranes of_ and _

Answer 37

Endomembrane system mitochondria and plastids

Question 38

● _ is the clear substance of the cytoplasm and is composed of water, enzymes, and other chemicals

Answer 38

Cytosol

Question 39

_ are small, spherical bodies that isolate reactions that produce or use hydrogen peroxide (H2O2).

Answer 39

Microbodies

Question 40

○ _ detoxify by-products of photosynthesis. ○ _ are involved in converting stored fats into sugars.

Answer 40

Peroxisomes Glyoxysomes

Question 41

Microtubules are structural elements of the cell that act as a “_.”

Answer 41

cytoskeleton

Question 42

○ The means of motility for organelles and whole cells. ○ Composed of two types of protein with a globular tertiary structure: _ and_. ○ Separate chromatids during cell division. ● _ are another component of the cytoskeleton. ● Assemblies of a globular protein called. ○ Involved in structure and movement

Answer 42

alphatubulin and beta-tubulin Microfilaments actin

Question 43

○ _ is sometimes converted into lipids and stored as large oil droplets. ○ Crystals of calcium oxalate or calcium carbonate. ○ Silica, tannins, or phenols. ○ Since there is no excretory mechanism, some of these products are simply stored waste.

Answer 43

Starch

Question 44

● Majority of plant cells have cell walls (except some sperm cells). ● Not only provides strength and protection but is also a site of considerable metabolism.

Answer 44

cell wall

Question 45

cell walls are primarily composed of

Answer 45

○ Cellulose ○ Hemicellulose ○ Pectins

Question 46

● Parallel cellulose molecules crystallize into _, which cover the plasma membrane. ○ Cellulose microfibrils are bound together by other polysaccharides called_ . ○ The wall of one cell is glued to the walls of adjacent cells by the middle lamella composed of _.

Answer 46

microfibrils hemicelluloses pectins

Question 47

● Plant cells have a thin _ _ _ . ● Cells requiring more strength may form a secondary, lignified cell wall between the primary wall and the plasma membrane.

Answer 47

primary cell wall

Question 48

● Cells of multicellular organisms interact and must communicate. ○ Interacting cells sense that they are part of a larger organism and identify how they should differentiate. ○ This requires extensive intercellular communication.

Answer 48

association of cells

Question 49

● Cells can secrete messenger compounds. ● Plant cells cannot communicate via direct physical contact. ○ In plants the cell wall and middle lamella are a barrier. ○ Plasmodesmata allows direct communication.

Answer 49

Association of cells

Question 50

_ are small channels that connect adjacent cells. ○ The plasma membrane passes through them and creates a contiguous membrane from cell to cell. ○ A small stream of the cystol and a section of the ER also pass through the plasmodesmata. ○ These occur singly or in clusters called primary pit fields.

Answer 50

Plasmodesmata

Question 51

● Plasmodesmata connect protoplasts to create the_.

Answer 51

symplast

Question 52

● Many cells do not abut each other tightly, so there is intercellular space between. ○ All intercellular space and cell walls together are called the _.

Answer 52

apoplast

Question 53

The _ and _ together make up the entire plant.

Answer 53

symplast and apoplast