Bio Chapter 4: 33-66

Question 1

Mitochondria

Answer 1

An organelle in eukaryotic cells that serves as the site of cellular respiration; uses oxygen to break down organic molecules and synthesize ATP.

Question 2

Chloroplasts

Answer 2

An organelle found in plants and photosynthetic protists that absorbs sunlight and uses it to drive the synthesis of organic compounds from carbon dioxide and water.

Question 3

Endosymbiont theory

Answer 3

The theory that mitochondria and plastids, including chloroplasts, originated as prokaryotic cells engulfed by host cells. The engulfed cell and host then evolve into a single organism.

Question 4

Cristae

Answer 4

An infolding of the inner membrane of a mitochondrion. The inner membrane houses electron transport chains and molecules of the enzyme catalyzing the synthesis of ATP.

Question 5

Mitochondria matrix

Answer 5

The compartment of the mitochondrion enclosed by the inner substrates for the citric acid cycle, as well as ribosomes and DNA.

Question 6

Thylakoids

Answer 6

A flattened, membranous sac inside a chloroplast. Thylakoids often exist in stacks called grana that are interconnected; their membranes contain molecular “machinery” used to convert light energy to chemical energy.

Question 7

Granum

Answer 7

A stack of membrane bound thylakoids in the chloroplast. Grana functions in the light reactions of photosynthesis.

Question 8

Stroma

Answer 8

The dense fluid within the chloroplast surrounding the thylakoid membrane and containing ribosomes and DNA; involved in the synthesis of organic molecules from carbon dioxide and water.

Question 9

Plastids

Answer 9

One of a family of closely related organelles that includes chloroplasts, chromoplasts, and amyloplasts. Plastids are found in the cells of photosynthetic eukaryotes.

Question 10

Peroxisome

Answer 10

An organelle containing enzymes that transfer hydrogen atoms from various substrates to oxygen, producing and then degrading hydrogen peroxide.

Question 11

Cytoskeleton

Answer 11

A network of microtubules, microfilaments, and intermediate filaments that extends throughout the cytoplasm and serves a variety of mechanical, transport, and signaling functions.

Question 12

Motor proteins

Answer 12

A protein that interacts with cytoskeletal elements and other cell components, producing movement of the whole cell or parts of the cell.

Question 13

Microtubules

Answer 13

A hollow rod composed of tubulin proteins that makes up part of the cytoskeleton in all eukaryotic cells and is found in cilia and flagella

Question 14

Centrosome

Answer 14

A structure present in the cytoplasm of animal cells that functions as a microtubule organizing center and is important during cell division. A centrosome has two centrioles.

Question 15

Centrioles

Answer 15

A structure in the centrosome of an animal cell composed of a cylinder of microtubule triplets arranged in a 9+0 pattern. A centrosome has a pair of centrioles.

Question 16

Cilia

Answer 16

A short appendage containing microtubules in eukaryotic cells. A motile cilium is specialized for locomotion or moving fluid past the cell; it is formed formed from a core of nine outer outer doublet microtubules and two inner single microtubules (the 9+0 arrangement)

Question 17

Flagella

Answer 17

A long cellular appendages specialized for locomotion. Like motion. Like motile cilia, eukaryotic flagella have a core with nine outer doublet microtubules and two inner single microtubules (the 9+2 arrangement) ensheathed in an extension of the plasma membrane. Prokaryotic flagella have a different structure.

Question 18

Basal body

Answer 18

A eukaryotic cell structure consisting of a “9+0” arrangement of microtubule triplets. The basal body may organize the microtubule assembly of a cilium or flagellum and is structurally very similar to a centriole.

Question 19

Dyneins

Answer 19

In cilia and flagella, a large motor protein extending from one microtubule doublet to the adjacent doublet. ATP hydrolysis drives changes in Dynein shape that lead to bending of cilia and flagella.

Question 20

Microfilaments

Answer 20

A cable composed of actin proteins in the cytoplasm of almost every eukaryotic cell, making up part of the cytoskeleton and acting alone or with myosin to cause cell contraction; also known as an actin filament.

Question 21

Myosin

Answer 21

A type of motor protein that associates into filaments that interact with actin filaments, causing cell contraction.

Question 22

Intermediate filaments

Answer 22

A component of the cytoskeleton that includes filaments intermediate in size between microtubules and microfilaments.

Question 23

Cell wall

Answer 23

A protective layer external to the plasma membrane in the cells of plants, prokaryotes, fungi, and some protists. Polysaccharides such as cellulose(plants/protists), chitin(fungi), and peptidoglycan(bacteria) , are important structural components of cell walls.

Question 24

Primary cell wall

Answer 24

In plants, a relatively thin and flexible layer that surrounds the plasma membrane of a young cell.

Question 25

Middle lamella

Answer 25

In plants, a thin layer of adhesive extracellular material, primary pectins, found between the primary walls of adjacent young cells.

Question 26

Secondary cell wall

Answer 26

In plant cells, a strong and durable matrix that is often deposited in several laminated layers around the plasma membrane and that provides protection and support.

Question 27

Extracellular matrix

Answer 27

The meshwork surrounding animal cells, consisting of glycoproteins, polysaccharides, and proteoglycans synthesized and secreted by the cells.

Question 28

Collagen

Answer 28

A glycoproteins in the extracellular matrix of animal cells that form strong fibers, found extensively in connective tissue and bone; the most abundant protein in the animal kingdom.

Question 29

Proteoglycans

Answer 29

A large molecule consisting of a small core protein with many carbohydrate chains attached, found in the extracellular matrix of animal cells. A proteoglycans May consist of up to 95% carbohydrates.

Question 30

Fibronectin

Answer 30

An extracellular glycoprotein secreted by animal cells m that helps then attach to the extra cellular matrix.

Question 31

Integrins

Answer 31

In animal cells, a transmembrane receptor protein with two subunits that interconnects the extracellular Matrix and the cytoskeleton.

Question 32

Plasmodesmata

Answer 32

An open channel though the cell wall that connects the cytoplasm of adjacent plant cells, allowing water, small solutes. And larger molecules.