Chapter 2 Cells

Question 1

Cell

Answer 1

basic functional unit of living things

Question 2

Plasma membrane

Answer 2

Bounds the cell and encloses the nucleus and the cytoplasm

• Separates internal metabolic events from the external environment.
• controls movement of materials in and out of the cell

Question 3

Ctoplasm

Answer 3

consists of specialized bodies called organelles which is suspended in the cytosol

Question 4

Cytosol

Answer 4

Consists of water and dissolved substances such as proteins and nutrients

Question 5

Lipid bilayer

Answer 5

Double phospholipid membrane with polar hydrophilic heads forming the outer faces and the nonpolar hydrophobic tails pointing toward the inside of the membrane

Question 6

Peripheral proteins

Answer 6

proteins that attach loosely to the inner or outer surface of the membrane

Question 7

Integral proteins

Answer 7

Proteins that extend into the membrane

Question 8

Transmembrane proteins

Answer 8

Integral proteins that expand through the membrane

Question 9

Fluid mosaic model

Answer 9

Scattered proteins within a flexible matrix of phospholipid molecules

Question 10

Phospholipid membrane

Answer 10

Selectively permeable that only small uncharged, polar molecules and hydrophobic molecules can pass across membrane
-large polar molecules, charged species such as ions are impermeable

Question 11

Channel Proteins

Answer 11

Provide open passageway though the membrane for hydrophilic substances (polar and charged species)

Question 12

Ion channels

Answer 12

allow passage of ions across the membrane

Question 13

Porins

Answer 13

Proteins that allow passage of CERTAIN ions through membranes

Question 14

Carrier protein

Answer 14

Bind to specific molecules, which is transferred to the other side of the membrane
-Doesn’t use energy, relies on conformational change!

Question 15

Transport protein

Answer 15

Use ENERGY ATP to transport materials across the membrane

Question 16

Active transport

Answer 16

When energy is used to transport molecules

Question 17

Recognition proteins

Answer 17

Give cell an identification which provides distinction between cell types
-Glycoproteins - have a short polysaccharide chain

Question 18

Adhesion proteins

Answer 18

attaches cells to neighboring cells

provides anchors for the internal filaments which gives stability to the cell

Question 19

Receptor Proteins

Answer 19

provide binding sites for hormones or trigger molecules

Question 20

Glycocalyx

Answer 20

Carbohydrate coat that covers the outer face of the cell wall for SOME bacteria and the plasma membrane of animal cells

Consist of oligosaccarides that are attached to membrane phospholipids and proteins

Question 21

Organelles

Answer 21

Bodies within the cytoplasm that separate the various metabolic reactions that occur within a cell

Question 22

Chromatin

Answer 22

When DNA is spread out like a threadlike matirx

Question 23

Chromosomes

Answer 23

When cell begins to divide, chromatin condenses into rod-shaped bodies

Question 24

Nucleosomes

Answer 24

bead and string. Organize DNA by wrapping it around histones (proteins)

Question 25

Nucleoli

Answer 25

Visible within the nucleus | Make ribosomes

Question 26

Ribosome

Answer 26

Subunits are made in the nucleus -consists of RNA and proteins 2 Subunits- 60s and 40s which move across the nuclear envelope into the cytoplasm which they are assembled into 80s ribosome Purpose: assists with the assembly of amino acids into proteins

Question 27

Endoplasmic reticulum

Answer 27

Flattened sacs and makes various materials

Question 28

Rough ER

Answer 28

Ribosomes are present creates glycoproteins by attaching polysaccharide groups to polyppetides

Question 29

Smooth ER

Answer 29

Does not have ribosomes Purpose: synthesis of lipids, hormones in liver cells- break down of toxics, drugs, and toxic by products

Question 30

Golgi apparatus

Answer 30

modify and package proteins and lipids into vesicles

Question 31

Lysosomes

Answer 31

Vesicles from golgi apparatus that has digestive enxymes Purpose: break down food, cellular debris, and foreign invaders like bacteria Has a low pH inside which is favorable to enzymes. This ensures that when an enzymes in a lysosome accidentally escapes, it will be inactive in the cytosol because it is only active in low pH

Question 32

Perioxisomes

Answer 32

Break down hydrogen peroxide, fatty acids, and amino acids. Commonly found in the liver and kidneys where they break down toxic substances

Question 33

Mitochondria

Answer 33

Carry out aerobic respiration, where energy is obtained through carbohydrates

Question 34

Chloroplast

Answer 34

Carry out photosynthesis | Encorporates energy from sunlight t make carbohydrates

Question 35

Cytoskeleton

Answer 35

Internal structure of the cytoplasm | Microtubules, intermediate filaments, and microfilaments are 3 protein fivers that are located in cytoskeleton

Question 36

Microtubules

Answer 36

Made up of TUBULIN Provide support and motility -also found in spindle apparatus

Question 37

Intermediate filaments

Answer 37

Provide support for maintaining the shape of the cell

Question 38

Microfilaments

Answer 38

Made of ACTIN Involved with cell motility ex. phagocytes

Question 39

Flagella and cilia

Answer 39

Flagella: long few and move in snake like motion. (sperm) Cilia: short and move with a back and forth movement (line respiratory tract and sweep away debris Has a 9+2 arrangement nine pairs of doubles Also has a basal body at the end

Question 40

Centrioles and basal bodies

Answer 40

act as microtubule organizing centers made up of 9 triplets of microtubules. PLANTS LACK CENTRIOLES only lower plants such as mosses and ferns have flagella and basal bodies

Question 41

Food vacuoles

Answer 41

Temporary store nutrients | usually merge with lysosomes to break down food

Question 42

Transport vessicles

Answer 42

move materials between organelles or to plasma membrane

Question 43

Storage vacuoles

Answer 43

IN PLANTS store starch, pigments, and toxic substances

Question 44

Central vacuoles

Answer 44

Large bodies occupying the interior of plant cells

Question 45

Turgor

Answer 45

When central vacuoles are fully filled and exert pressure on the cell walls -this maintains the rigidity of the cell Function: Store nutrients and act as lysosomes for plant cells

Question 46

Contractile Vacuoles

Answer 46

Organelles in SINGLE CELLED ORGANISM that collects and pump excess water out of the cell

Question 47

Cell Walls

Answer 47

Found: plants, fungi, protists, bacteria Develop outside the plasma membrane and provide support for the cell

Question 48

Cellular Junctions

Answer 48

Anchor cells to one another or provide passageway for cellular exchange

Question 49

Anchoring junctions

Answer 49

Protein attachments between adjacent animal cells ex. desmosomes. Bind to adjacent cells which provides mechanical stability to tissues

Question 50

Tight junctions

Answer 50

Tightly stitched seams between animal cells This makes a seal which prevents passage of materials between cells. Commonly found in the digestive tract. Materials are required to pass through cells and not intercellular spaces in order to go into the blood stream

Question 51

Communicating junctions

Answer 51

Passageways between cells that allow transfer of chemical or electrical signals. Has 2 types: Gap junctions and Plasmodesmata.

Question 52

Gap junctions

Answer 52

Narrow tunnels between animal cells that consists of proteins called CONNEXINS (CONNECT!!!) This prevents cytoplasms from mixing but allows the passage of ions and small molecules Allow communication between cells through the exchange of materials or through the transmission of electrical impulses.

Question 53

Plasmodesmata

Answer 53

Narrow channels between plant cells