Unit 11

Question 1

Define cell

Answer 1

the basic unit of life

Question 2

What are the components of cell theory?

Answer 2

All living things are composed of cells.
Cells are the basic units of structure and function in living things.
New cells are produced from existing cells.

Question 3

Define nucleus

Answer 3

large, membrane-enclosed structure that contains the cell’s genetic material in the form of DNA; it controls many of the cell’s activities

Question 4

Define eukaryotes

Answer 4

cells that contain nuclei and have membrane-bound organelles

Question 5

Define prokaryotes

Answer 5

cells that do not contain nuclei and do not have membrane-bound organelles

Question 6

Define organelles

Answer 6

cell structures that do specialized things

Question 7

Define cytoplasm

Answer 7

portion of the cell inside the nucleus

Question 8

Define cell membrane

Answer 8

a flexible barrier that surrounds all cells

Question 9

Define cell wall

Answer 9

a strong supporting layer around the membrane in plant cells

Question 10

Define lipid bilayer

Answer 10

a double-layered sheet of lipids

Question 11

Define concentration

Answer 11

the mass of a solute in a given volume of solution, or mass/volume

Question 12

Define equilibrium

Answer 12

a state where the concentration of the solute is the same throughout a system

Question 13

Define isotonic

Answer 13

the concentrations of solutes is the same inside and outside the cell

Question 14

Define hypertonic

Answer 14

the solution has a HIGHER solute concentration than the cell

*remember: the root “hyper-“ means higher

Question 15

Define hypotonic

Answer 15

the solution has a LOWER solute concentration than the cell

*remember: the root “hypo-“ means lower

Question 16

Define passive transport

Answer 16

a type of membrane transport that does not require energy

Question 17

Define simple diffusion (or diffusion)

Answer 17

the process by which particles move from an area where they are more concentrated to an area where they are less concentrated

Question 18

Define facilitated diffusion

Answer 18

molecules that cannot diffuse across the cell membrane’s lipid bilayer on their own move through protein channels instead (cell membrane channels facilitate diffusion)

Question 19

Define osmosis

Answer 19

the diffusion of water through a selectively permeable membrane

Question 20

Define active transport

Answer 20

an energy-requiring process to move molecules across the cell membrane against their concentration gradient

Question 21

Define endocytosis

Answer 21

the process of taking material into the cell by means of infoldings, or pockets, of the cell membrane

Question 22

Define phagocytosis

Answer 22

extensions of cytoplasm surround a particle and package it within a food vacuole, then engulfs it

Question 23

Define pinocytosis

Answer 23

cells take up liquid from the surround environment, tiny pockets form along the cell membrane, fill with liquid, and pick off to form vacuoles within the cell

Question 24

Define exocytosis

Answer 24

membrane of the vacuole surrounding the extra material fuses with the cell membrane and forces the contents out of the cell

Question 25

Define cell division

Answer 25

the process by which a cell divides into two new daughter cells

Question 26

Define mitosis

Answer 26

first stage of cell division; division of the cell nucleus

Question 27

Define cytokinesis

Answer 27

division of the cytoplasm

Question 28

Define chromatids

Answer 28

identical sister pairs which can be put together as a chromosome

Question 29

Define centromeres

Answer 29

the central attachment point of a pair of chromatids

Question 30

Define interphase

Answer 30

an “in-between” period of growth

Question 31

Define cell cycle

Answer 31

a series of events that cells go through as they grow and divide

Question 32

Define spindle

Answer 32

a fan-like microtubule structure that helps separate the chromosomes

Question 33

Define nondisjunction

Answer 33

the most common error in meiosis wherein homologous chromosomes fail to separate

Question 34

Define Barr body

Answer 34

highly condensed X-chromosome

Question 35

Define X-chromosome inactivation

Answer 35

the turning off of one x chromosome in female cells

Question 36

Cell membrane: parts and functions

Answer 36

Found in all cells Thin layer of phospholipids and proteins that separate the cell’s contents from the environment 5-10 mm thick (not important) Controls transport of substances in and out of the cell Stabilized by cholesterol and have outward facing heads (hydrophilic), inward facing tails (hydrophobic) Proteins that help with function

Question 37

What are three kinds of membrane proteins and what do they do?

Answer 37

Transport proteins: regulate the movement of water soluble molecules through the membrane Receptor proteins: sets off a cellular response when specific molecules bond to them Recognition/marker proteins: identify the cell as part of self or as a particular kind of organism

Question 38

Cytoplasm: parts and functions

Answer 38

Found in all cells Made of cytosol (semifluid substance made primarily of water and organic compounds) Contains organelles that perform specialized functions

Question 39

Cytoskeleton: parts and functions

Answer 39

``` Found in all cells A network of protein fibers and tubes found throughout the cytoplasm Gives support Roadways Cell transport ```

Question 40

Nucleus: parts and functions

Answer 40

Found in plant and animal cells Contains nearly all the cell’s DNA and with it the coded instructions for making proteins and other important molecules Surrounded by a double layer of phospholipid called nuclear envelope Nuclear pores allow mRNA and other materials a way in and out Nucleolus forms ribosomes Contains chromatin which can condense into chromosomes

Question 41

Ribosome: parts and functions

Answer 41

Found in all cells Proteins are assembled on ribosomes. Small particles of RNA and protein

Question 42

Endoplasmic reticulum: parts and functions

Answer 42

Smooth ER transitional area for transport vesicles carbohydrate and lipid synthesis Rough ER manufactures membranes synthesizes proteins

Question 43

Golgi apparatus: parts and functions

Answer 43

Found in plant and animal cells Modifies, sorts, and packages proteins and other materials from the endoplasmic reticulum for storage in the cell or secretion outside the cell

Question 44

Lysosome: parts and functions

Answer 44

Found in plant and animal cells Small organelles filled with enzymes that digest lipids, carbohydrates, and proteins into small molecules that can be used by the rest of the cell Break down organelles that have outlived their usefulness

Question 45

Vacuoles: parts and functions

Answer 45

Found in plant and animal cells Sac-like structures that store materials such as water, salts, proteins, and carbohydrates Maintains homeostasis through water control and storage

Question 46

Mitochondria: parts and functions

Answer 46

Contains its own DNA Convert chemical energy stored in food into compounds that the cell can use Power-house of the cell

Question 47

Chloroplasts: parts and functions

Answer 47

Found in plant cells Organelles that capture energy from sunlight and convert it to chemical energy in photosynthesis Contains its own DNA

Question 48

Centriole: parts and functions

Answer 48

``` Found in animal cells Located near the nucleus Organizes cell division Not found in plant cells Made of tubulin ```

Question 49

Cell wall: parts and functions

Answer 49

Found in plant cells | Provides support and protection for the cell

Question 50

Microfilaments: parts and functions

Answer 50

Threadlike structures made of actin. Make extensive networks to support the cell and help them move. They assemble and disassemble to allow for cytoplasmic movement, allowing amoebas to crawl along surfaces.

Question 51

Microtubules: parts and functions

Answer 51

Hollow structures made out of proteins called tubulins. Help maintain cell shape and form the mitotic spindle, which is needed in cell division. Build projections on the surface of the cell called cilia for movement in water

Question 52

What is found in plant cells?

Answer 52

cell wall, chloroplast, large vacuole

Question 53

What is found in animal cells?

Answer 53

no cell wall, no chloroplasts, small vacuoles, has centrioles

Question 54

What is osmosis?

Answer 54

The diffusion of water through a selectively permeable membrane

Question 55

What are the two problems that all cells that grow large face?

Answer 55

Not enough space in nucleus for transcription (greater DNA demands). Problems with surface area to volume ratio (difficulty exchanging material)

Question 56

What happens in the G1 phase?

Answer 56

Cells do most of their growing | Increase in size and make new proteins and organelles

Question 57

What happens in the S phase?

Answer 57

DNA replication All chromosomes replicated Chromosomes consist of 2 sister chromatids in chromatin form now

Question 58

What happens in the G2 phase?

Answer 58

Second growth phase Reproduction of some organelles High microtubule production Cells grow in size

Question 59

What happens in the G0 phase?

Answer 59

Usually for non-dividing cells (muscle, nerve, or senescent cells) Can occur for cells that are damaged as an alternative to apoptosis Can be temporary or permanent Gap phase while in a resting state or performing assigned duties

Question 60

Order of mitosis

Answer 60

``` Prophase Metaphase Anaphase Telophase (PMAT) Cytokinesis ```

Question 61

What happens in Prophase?

Answer 61

``` (positioning) Longest phase of mitosis Chromosomes condense Centrioles separate and take up positions on opposite sides of nucleus Nuclear envelope breaks down Mitotic spindles form ```

Question 62

What happens in Metaphase?

Answer 62

(middle) “Tug and pull” of spindle brings the chromatids to the middle of the cell Each centromere is connected to the two poles of the spindle by microtubules

Question 63

What happens in Anaphase?

Answer 63

[away] Chromosomes move to opposite poles The sister chromatids are pulled away from each other into individual chromosomes

Question 64

What happens in Telophase?

Answer 64

[two] Two daughter nuclei form in the cell Two new nuclear envelopes form Chromosomes unwind forming chromatin

Question 65

What happens in Cytokinesis?

Answer 65

The cytoplasm splits | Two daughter cells are created

Question 66

What are the four functions of the cell membrane?

Answer 66

To isolate the cell cytoplasm from the environment. To regulate the exchange of essential substances between the cytoplasm and the external environment. To communicate with other cells. To identify the cell as belonging to a particular organism.