Chapter 3: Cells Flashcards

1
Q

plasma membrane

A
  • defines boundaries of the cell
  • regulates passage of substances in and out of cell
  • consists of phospholipids, cholesterol, and protein
  • selectively permeable
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2
Q

phospholipids

A
  • have hydrophilic heads
  • have twin hydrophobic tails
  • position themselves in a bilayer
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3
Q

selective permeability

A

allows some substances to pass through easily, but not others

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4
Q

nucleus

A
  • cell’s control center
  • contains genetic information
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5
Q

nuclear envelope

A

double-layered membrane surrounding the nucleus

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6
Q

nucelar pores

A
  • perforate the nuclear envelope
  • regulate the passage of molecules in and out of the nucleus
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7
Q

nucleolus

A
  • center of the nucleus
  • manufactures components of ribosomes
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8
Q

chromatin

A
  • thread-like structures
  • composed of DNA and protein
  • throughout the nucleoplasm
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9
Q

organelles

A
  • “little organs”
  • perform specific tasks in cellular metabolism
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10
Q

endoplasmic reticulum (ER)

A
  • network of membranous tubules within the cytoplasm of a cell
  • rough ER has ribosomes on the surface
  • proteins synthesized by the ribosomes move through the ER’s canals toward the Golgi apparatus
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11
Q

ribosomes

A

granules of protein and RNA attached to the ER and scattered throughout the cell

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12
Q

Golgi apparatus

A
  • prepares proteins and packages them for export to other parts of the body
  • the “post office” of the cell
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13
Q

centrioles

A

bundles of microtubules that aid in cell division

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14
Q

lysosomes

A
  • membranous vesicles that contain enzymes that help break down protein the cell doesn’t need
  • the “garbage disposal” of the cell
  • form from pinched off pieces of the Golgi apparatus
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15
Q

mitochondria

A
  • the powerhouse of the cell
  • converts organic compounds into ATP
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16
Q

cytoskeleton

A
  • supporting framework of the cell
  • determines the shape of the cell
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17
Q

microvilli

A
  • folds of the cell membrane that greatly increase surface area of the cell
  • can increase the cell’s absorptive area by as much as 40x
  • often found in cells responsible for absorbing nutrients
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18
Q

cilia

A
  • hair-like processes on the surface of the cell
  • move in waves of the same direction
  • occur mostly in the respiratory tract and in fallopian tubes
  • help move mucus and foreign particles out of the lungs
  • help propel an egg cell or or embryo toward the uterus
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19
Q

flagella

A

tail of a sperm cell

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20
Q

passive transport

A
  • movement of ions and other substances across cell membranes without the need of energy
  • diffusion, osmosis, filtration, and facilitated diffusion
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21
Q

diffusion

A
  • the movement of particles from an area of higher concentration to an area of lower concentration
  • occurs in air or water
  • continues until equilibrium is reached
22
Q

equilibrium

A

the point at which diffusion no longer occurs (when particles are evenly distributed)

23
Q

concentration gradient

A
  • a difference in concentration of a substance from one point to another.
  • when particles move from an area of greater concentration to an area of lesser concentration, they move DOWN the concentration gradient
24
Q

osmosis

A
  • the diffusion of water down the concentration gradient through a selectively permeable membrane
  • often happens when a particular substance can’t cross the membrane
25
Q

hydrostatic pressure

A

pressure exerted by water

26
Q

osmotic pressure

A
  • water pressure that develops in a solution as a result of osmosis
  • when the volume of water in a cell increases, the water exerts more pressure against the membrane
  • the more solute there is in a solution, the greater its osmotic pressure
27
Q

tonicity

A

the ability of a solution to affect the fluid volume and pressure in a cell through osmosis

28
Q

isotonic solution

A

a solution in which the concentration of solute is the same as inside of the cell

29
Q

hypertonic

A

a solution that contains a higher concentration of solute than the fluid within the cell. water will exit the cell via osmosis (shrivel) and possibly die

30
Q

hypotonic

A

a solution that contains a lower concentration of solute than the fluid within a cell. the water will move via osmosis into the cell (swell) and eventually burst (lysis)

31
Q

filtration

A
  • occurs because of differences in pressure
  • water and dissolved particles are forced across a membrane from an area of higher to an area of lower hydrostatic pressure
  • commonly occurs in capillaries
32
Q

facilitated diffusion

A

transport process involving diffusion of a substance through a channel protein

33
Q

active transport

A
  • solutes move from areas of lower concentration to areas of greater concentration (up the concentration gradient)
  • requires energy (ATP)
34
Q

sodium-potassium pump

A
  • regulates the volume of fluid within cells
  • provides the electrical potential necessary for nervous system activity
  • helps in heat production
  • fluid inside cells contains lower levels of sodium and higher levels of potassium than the fluid outside the cell
  • the sodium-potassium pump continues to transfer sodium out of the cell (extracellular area) and potassium into the cell (intracellular area)
35
Q

endocytosis

A

form of vesicular transport that brings substances into the cell

36
Q

phagocytosis

A
  • “cell eating”
  • cell engulfs a solid particle and brings it into the cell
37
Q

pinocytosis

A
  • “cell drinking”
  • tiny vacuoles bring droplets of extracellular fluid containing dissolved substances into the cell
38
Q

exocytosis

A
  • vesicles release substances outside of the cell
  • glands use this method to release hormones
39
Q

DNA

A

deoxyribonucleic acid

40
Q

genome

A

complete set of genetic material in a cell

41
Q

polymer

A

a large molecule made up of many smaller molecules joined together in a sequence

42
Q

nucleotides

A

the building blocks of DNA

they consist of:
- one sugar
- one phosphate group
- one of four nitrogenous bases

43
Q

nitrogenous bases in DNA

A
  • adenine (A)
  • thymine (T)
  • guanine (G)
  • cytosine (C)

A pairs with T
G pairs with C

44
Q

RNA

A
  • ribonucleic acid
  • only a single strand
  • contains the base uracil (U) instead of thymine
45
Q

3 forms of RNA

A
  • messenger (mRNA)
  • transfer (tRNA)
  • ribosomal (rRNA)
46
Q

transcription

A

a portion of DNA unwinds, a new complimentary strand of mRNA is formed, then the new mRNA strand separates from the DNA and moves through a nuclear pore and into the cytoplasm

47
Q

translation

A

the mRNA strand attaches to a ribosome. the ribosome moves along the strand and reads the codons. tRNA waits in the cytoplasm with an anticodon that will compliment a specific site on the mRNA. the tRNA finds its complimentary bases and deposits the amino acid. the ribosome uses enzymes to attach the chain of amino acids together with peptide bonds, forming a protein

48
Q

codon

A

a triplet of nucleotides that codes for a specific amino acid

49
Q

Interphase

A
  1. first gap phase (G1) - synthesis of components needed for DNA
  2. synthesis phase (S) - DNA replication
  3. second gap phase (G2) - preparation for mitosis
50
Q

Mitosis

A
  1. prophase
  2. metaphase
  3. anaphase
  4. telophase