Bio Test #6 Flashcards Preview

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Flashcards in Bio Test #6 Deck (166):
1

Where do eukaryotic cells occur?

Eukaryotic cells occur in algae, protozoa, fungi, plants, & animals

2

What are characteristics of Eukaryotic cells?

Euk. cells can be unicellular or multicellular, from 5 micrometers to 100 micrometers

3

How are eukaryotic cells characterized?

They are characterized by nucleus & organelles

4

What are the 2 types of Endoplasmic Reticulum?

Smooth ER & Rough ER

5

What is the structure of smooth ER?

has a network of tubules & vesicles around the nucleus (sometimes continuous with the nucleus); membrane bound organelle

6

What are functions of Smooth ER?

synthesis of lipids, breaks down carbohydrate, detoxify from drugs, regulates calcium concentration in the cell, produces sex hormones

7

What is the structure of Rough ER?

has a network of tubules & vesicles (sometimes continuous with nuclear membrane); membrane bound organelle; studded with ribosomes (gibing it a rough appearance)

8

What are the functions of Rough ER?

synthesis of protein that are needed on the cell membrane of the cell; rough ER surrounds protein with a vesicle

9

What is the structure of Golgi Apparatus?

series of membrane bound stacks called cisterna(ae)

10

What are the functions of Golgi Apparatus?

works with ER to repackage & transform proteins or lipids & send them to the right destination; vesicles from ER fuse with cisternae, each region of the Golgi contains enzymes that modify the content of the vesicle

11

What is the structure of mitochondrian?

double membrane organelle; inner membrane folds & increases its surface and forming crista/ae; fluid inside is called matrix & contains ribosomes and genetic material & enzymes

12

What is the function of mitochondria?

production of ATP

13

What is the structure of lysosomes?

membrane bound organelle made by Golgi; it contains digestive enzymes

14

What is the function of Lysosomes?

digest worn out organelles, food, engulfed bacteria or viruses

15

What is the structure of ribosomes?

non-membrane bound organelles; made of rRNA & proteins & consist of 2 subunits

16

What is the function of ribosomes?

protein production (protein that remain in the cell)

17

What is the structure of centroiles?

barrel shaped organelle made of proteins; part of centrosome

18

What is the function of centroiles?

involved with the organization of mitotic spindle

19

What is the structure of Nuclear Envelope?

double membrane; has pores; impermeable to most substance

20

What is the function of Nuclear Envelope?

protect genetic material; regulate what moves in & out of nucleus

21

What is the structure of DNA?

deoxyribonucleic acid

22

What is the structure of Chromosomes?

protein & DNA forms chromatin, arranged into a chromosomes

23

What are the functions of DNA & Chromosomes?

long term storage of info, controls activity of cell, passes genetic info to daughter cell.

24

What are characteristics of Mitochondrian?

range in size from 1 to 10 micrometers; different cells have different numbers of mitochondria

25

What is the structure of cell wall?

Its made of cellulose and has 3 layers

26

Cellulose

arranged into bundles of fibers called microfibrils

27

What are the functions of the cell wall?

maintains shape of cell, prevents cell from bursting, allows plant to grow against gravity

28

What are the 3 layers of the cell wall?

Primary Cell wall (outside)
Middle Lamella
Secondary Cell Wall (inside)

29

What is the structure of Chloroplast?

double membrane organelle

30

What is the function of chloroplast?

site of photosynthesis

31

stroma

liquid inside chloroplast and contains ribosomes, enzymes, & DNA loop

32

What is the structure of Central Vacuole?

liquid filled vacuole containing water, enzymes, waste, toxic substances

33

What are the functions of Central Vacuole?

storage of water, support, defense

34

What are differences of animal cells compared to plants?

no cell wall, has glycogen as carb storage, roundish shape (flexible), no chloroplasts, no vacuoles or temporary vacuoles, has cholesterol in cell membrane, has centrioles

35

What are differences of plant cells compared to animals?

has cell wall, plants have starch as carb storage, rectangular shape (fixed), have chloroplast always has central vacuoles, do not have cholesterol in cell membrane, has no centrioles

36

cell membrane

a selectively permeable phospholipid bilayer found in all cells

37

What is the structure of a phospholipid?

has 3 parts: phospho alcohol head, glycerol, fatty acid tail

38

Which part of phospholipid is hydrophilic?

the polar phospho alcohol head

39

Which part of a phospholipid is hydrophobic?

the non-polar fatty acid tails

40

Why do phospholipids tend to arrange into a bilayer that has continuous & spherical shape?

because of the polar head & non-polar tail

41

Why is the plasma membrane very flexible & can be broken with enough force?

because the tails are just close to each other but do not form bonds

42

What allows endo & exocitosis?

the plasma membrane's flexibility

43

plasma membrane

semi-permeable membrane & can control what goes in & out of the cell

44

Why do animal cells have cholesterol interspersed between the phospholipids?

It ensures that the membrane can function at a wider range of temperature

45

Why do plant cells have a mix of saturated & unsaturated fatty acids?

to allow the membrane to function at different temperatures

46

What are the types of proteins found in cell membrane?

integral, peripheral, glycoproteins

47

integral

embedded in the phospholipid membrane, can have many functions (transport, enzyme, hormone binding site, cell adhesion)

48

Peripheral

adheres temporarily to the cell membrane
can attach to integral protein

49

glycoproteins

protein & carbohydrate tail
important for cell recognition

50

What can movements of substances be?

passive and active

51

Passive

without use of energy (ATP)

52

Active

needs energy to occur (ATP)

53

What are types of Passive Transports?

Diffusion and Osmosis

54

diffusion

the passive movement of particles from an area of high concentration to an area of low concentration

55

What are types of diffusion?

simple (unaided) and facilitated

56

Why does diffusion occur?

it results from the random motion of particles

57

high concentration

an area with lots of molecules

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low concentration

an area with few molecules

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concentration gradient

difference between high and low

60

What does it mean when molecules move along the concentration gradient?

that molecules move from an area of high concentration to an area of low concentration

61

What does it mean when molecules move against the concentration gradient?

to move from low concentration to high concentration

62

What are factors that affect rate of diffusion?

concentration gradient (greater the concentration difference between 2 areas, the greater diffusion)
distance involved
area involved
barrier to diffusion

63

distance involved

diffusion over a short distance is faster then diffusion over a long distance

64

area involved

the larger the area, the greater the diffusion

65

barrier to diffusion

thinner the membrane the faster the diffusion

66

What are characteristics of simple diffusion?

through membrane, through channel protein, used for small uncharged molecules (cell membrane) or small & charged (channel protein)

67

Why isnt energy needed for simple diffusion?

No energy needed because molecule move WITH concentration gradient

68

What are characteristics of facilitated diffusion?

non channel protein, non channel protein binds to the substance to be moved changes shape & moves substance in, moves larger molecules

69

Why isn't energy needed for facilitated diffusion?

does not need energy because substances are moved with the concentration gradient

70

Why is facilitated very specific?

because each substance will need a different non-channel protein

71

osmosis

passive movement of water across a semi-permeable membrane, from low solute concentration to high solution concentration

72

aquaporin

protein water moves through

73

What are types of active transports?

pumps, exocytosis, endocytosis

74

How do molecules move in active transports?

molecules move against the concentration gradient (from low concentration to high concentration)

75

What are characteristics of pumps?

pumps are proteins embedded in the cell membrane, and specific (they can transport only certain molecules) and take the name of whatever they transport

76

What are the steps of the mechanism of pumps?

1. 3 sodium molecules bind to pump in a specific site. Binding of sodium uses ATP phosphorylation
2. phosphorylation of ATP releases energy. This energy is used to change the shape of the pump
3.Sodium can be released outside the cell & 2 potassium molecules move in to attach to a specific site different from where the sodium had attached
4. the binding of potassium to the pump causes the release of the phosphate group. This makes the pump revert to its original shape
5. potassium can be released inside the cell. Pump is ready to start again

77

What are functions of membrane proteins?

Cell recognition, cell adhesion, receptors, enzyme, and transport

78

In membrane proteins, what's cell recognition?

Using glycoproteins you identify body's own cells from foreign cells

79

In membrane proteins, what's cell adhesion?

Proteins bind to one another & hold cells together
Connections are called junctions and can be temporary or permanent

80

In membrane proteins, what's receptors?

Respond to a chemical messenger & sends a signal inside the cell

81

In membrane, what's enzyme?

Breaks down a chemical messenger
Sometimes more enzymes are grouped together to form a metabolic pathway

82

What's another name for receptors?

Hormone Binding Sites

83

In membrane, what's transport?

it consists of pumps and channels

84

What's a membrane protein's passive & active transport?

pumps are active transports
channels are passive transports

85

channels

passive transport that allows water & hydrophilic molecules to move through

86

What are the 2 types of channels?

open & gated

87

What are the 3 types of gated channels?

ligand, voltage, mechanical

88

ligand

a chemical messenger opens the gate

89

voltage

a change in electric potential that opens the gate

90

mechanical

gate responds to a physical stress (pressure, stretch)

91

cell cycle

describes the behavior of the cell as it grows and reproduces

92

What are the 2 phases of the cell cycle?

interphase & cell division

93

interphase

the longest phase of cell cycle & cells can be found in this phase about 80% of the time

94

What are the 3 phases of interphase?

G1, S, G2

95

What are the 2 phases of cell division?

mitosis and cytokinesis

96

G1 phase

cell has just finished mitosis and the cell is as small as it can be

97

S phase

synthesis; DNA duplicates (chromosomes make a copy of themselves); cell continues to grow; synthesis of proteins and enzymes involved in DNA duplication

98

G2 phase

final chance for cell to grow & check up to ensure cell is ready to start dividing

99

Checkpoint G1

Between G1 & S, proteins check to see if the cell is healthy & the correct size to divide. if it is, the proteins will initiate DNA duplication. If not, the cell will remain in G1 phase

100

Checkpoint G2

between G2 & Mitosis, DNA repair enzymes check to see if DNA is duplicated correctly. If it is, the protein will send signal to begin mitosis

101

Mitosis

starts with a deploid cell (2n) & produces 2 identical deploid daughter cells

102

prophase

nuclear envelope begins to disappear, chromosomes condense (becoming visible), centrioles start migrating to opposite poles, spindle starts forming & attaches to the chromosomes in the centromere

103

metaphase

chromosomes line up on the equator of the cell (cellplate or metaphase plate), centrioles are at opposite poles

104

What are the 4 phases of mitosis?

prophase, metaphase, anaphase, telophase

105

Anaphase

Sister chromatids are pulled apart
Chromosomes move towards opposite poles

106

Telophase

Chromosomes arrive at opposite poles
Chromosomes start to elongate
Nuclear membrane reappears
Nucleolus reappears
Spindle disappears
Cell starts elongating for cytokinesis

107

Cytokinesis

Division of cytoplasm & organelles inside the cell

108

What's cytokinesis in animal cells?

Cell membrane starts folding in forming a cleavage furrow. Eventually the 2 sides meet up & the cell separates

109

What's cytokines In plant cells?

Golgi releases vesicles that contain cellulose
Vesicles fuse & start forming a cell plate in the middle of a cell
Cell plate grows & separate the cell

110

What are the functions of mitosis?

Tissue repair
Tissue growth
Asexual reproduction (marine invertebrate

111

hypertonic

have more solute than the solution it is compared to

112

isotonic

2 solutions will have the same concentration

113

hypotonic

solution will have less concentration of a solute than the solution it is compared to

114

tumor

when cells lose proper control of cell division and start dividing uncontrollably which forms a mass

115

What are the 2 types of tumors?

benign and malignant

116

benign

tumor that does not have the potential to spread

117

malignant

have the potential to spread

118

metastasize

when a piece can break off and move to other organs through blood system

119

What are the steps of malignant?

1. malignant tumor
2. angiogenesis

120

angiogenesis

tumor that has recruited blood vessels to get nutrients to keep growing in size, which can form metastasis. If tumor is malignant then patient has cancelled

121

carcinogens

substances associated with an increased risk of contracting cancer

122

What gene is associated with cancer?

TP53 when turned off

123

What are factors that increase the risk of cancer?

radiations, chemicals, tobacco, stress/life, genetics, viruses

124

What causes a mutation called a thymine dimer?

UV radiators

124

What forms a kink on the DNA strand?

Two neighboring thymines on the same stand, detach from their partner and form a covalent bond between them

125

What can repair the kink in a DNA strand?

DNA repair enzymes

126

What happens to dimers that are not repaired?

It can cause cancer

127

Why don't some organisms get skin cancer?

They have DNA repair enzymes called photolyase

128

Gene therapy

Insert gene to make the enzyme in people at high risk

129

How are proteins made?

Instructions in DNA: cells make a copy of DNA (mRNA). Then it reads codons, making the protein

130

mRNA

One stranded with bases of Adenine, Cytosine, Guanine, Uraci
It is always made from matching 3' to 5' strand

131

Codon

A group of 3 bases

132

What does a codon correspond to?

1 amino acid

133

What reads codons in mRNA?

Ribosomes

134

How do ribosomes read codons?

They attach to mRNA and start sliding along until it finds the start codon and keeps sliding along (reading codons) until it finds a stop codon

135

What are the 3 stop codons?

UAA
UAG
UGA

136

How do we know what amino acids correspond to certain codons?

Through the genetic code table

137

What are the characteristics of the genetic code?

Universal and degenerate

138

Universal

Works in the same way in every organism

139

Degenerate

More than one codon can call in the amino acid

140

What starts every protein?

AUG starts every protein with the same amino acid methionine

141

Gene mutation

A change in the base sequence of an allele

142

What may gene mutations produce?

It may produce a different allele if the codon codes for a different amino acid

143

What are different types of mutations?

A mutation can be positive, negative, or neutral

144

Positive mutation

Causes an advantage

145

Negative mutation

Causes a disadvantage

146

Neutral mutation

Causes now effect

147

What's the frequency if mutations have advantages to the environment?

The frequency will be higher

148

What's the frequency if mutations have disadvantages to the environment?

Frequency will be lower

149

Mutagens

Substances that cause mutations

150

How do mutations occur?

Through substitutions, insertions, and deletions

151

Substitutions

One base is replaced with another

152

Insertions

One base is added

153

Deletions

One base is removed

154

A mRNA strand has 27 codons. How many amino acids in this polypeptide?

26 because you don't count the stop codon

155

A gene is 6009 base pairs long. How many amino acids in the polypeptide?

After dividing by three and not counting the stop codon, there are 2002 amino acids

156

What do the codons UUA, CUA, CUG have in common?

They all have the same amino acid

157

Karyotype

Number and appearance of chromosomes of a specific organism

158

How are chromosomes paired?

By size, shape, banding, & position of centromere

159

When do scientists take pictures of cell for karyotyping?

In metaphase when the chromosomes are most visible

160

What does each cell contain considering chromosomes?

Each chromosome is made if 2 sister chromatids.
Each cell has to chromosomes for each pair (one father & one mother)

161

Compare human sex chromosomes

In 23rd position/pair
Female are XX and the same size chromosomes
Male are XY and different size chromosomes

162

What is karyotype used for?

It is used for pre-natal Diagnosis

163

Prenatal Diagnosis

Prenatal (before birth)
Diagnosis (to identify something)

164

Aminocentesis & Chorionic Villus Sampling

Two tests used to obtain cells from fetus. Which take advantage of the fact that the placenta, amnion, & chorion are made by fetus & not mother. There fore the cells of these tissues will have the genotype of the baby

165

Amniocentesis

Removal of amniotic fluid; done at 14 weeks pregnant; fluid is extracted with syringe inserted into the abdominal wall; liquid extracted contains cells from fetus and is centrifuged, the cells are extracted and cultured. Cultured cells can be karyotyped. The liquid can be tested for neurological disorders (spina bifida)