Botany Section 3

Front 1

DNA

Back 1

deoxyribose nucleic acid; how eukaryotic cells carry their genetic information

Front 2

What is DNA made of?

Back 2

deoxyribose, phosphate and a nucleotide

Front 3

Who discovered the structure of DNA?

Back 3

Watson and Crick with the help of franklin

Front 4

purines

Back 4

adenine and guanine due to similar structures

Front 5

pyridamines

Back 5

cytosine and thymine with similar structures

Front 6

adenine pairs with?

Back 6

thymine

Front 7

guanine pairs with?

Back 7

cytosine

Front 8

how was DNA to be shown as helical?

Back 8

xray cartography by franklin showed an X

Front 9

How are the bases of DNA joined together?

Back 9

hydrogen bonds

Front 10

how many bonds are between A and T

Back 10

2 hydrogen bonds

Front 11

how many bonds are between C and g?

Back 11

3 hydrogen bonds

Front 12

antiparallel

Back 12

opposite, running the opposite direction

Front 13

complementary strand

Back 13

each strand contains the paired bases to the other strand

Front 14

essential property of genetic material

Back 14

the ability to copy itself.

Front 15

origins of replication

Back 15

specific nucleotide sequence that initiates the replication process

Front 16

helicases

Back 16

required to initiate DNA replication by breaking the hydrogen bonds

Front 17

dna polymerase

Back 17

enzyme that catalyzes the synthesis of a new DNA strand

Front 18

replication bubble

Back 18

the localized regions of synthesis which form at the many origins of replication along the DNA molecule

Front 19

replication fork

Back 19

at the ends of the bubble where the strands of DNA are separated into a fork

Front 20

bidirectional

Back 20

the two replication forks move in opposite directions

Front 21

Which direction does DNA polymerase syntehsize in?

Back 21

5'-3'

Front 22

leading strand

Back 22

newly synthesized DNA that is continuous from the beginning of replication

Front 23

lagging strand

Back 23

newly synthesized DNA that is in fragments

Front 24

okazaki fragments

Back 24

fragmented DNA of lagging strand

Front 25

DNA ligase

Back 25

connects the okazaki fragments

Front 26

daughter cells

Back 26

the contents of a cell are split between two new cells

Front 27

why does replication occur?

Back 27

to replace old cells, growth, or reproduction

Front 28

mitosis

Back 28

nuclear division; a complete set of previously duplicated chromosomes is allocated to each of the daughter cells nuclei

Front 29

cytokinesis

Back 29

a process that divides the entire cell into two new cells

Front 30

cell cycle

Back 30

a regular, repeated sequence after and before mitosis

Front 31

interphase

Back 31

precedes and follows mitosis divided into three phases; G1, S1 and G2

Front 32

M-phase

Back 32

cytokinesis and mitosis together

Front 33

initials

Back 33

plant cells that pass through successive cell cycles

Front 34

apical meristem

Back 34

immediate derivatives of initials located at the tips of roots and shoots

Front 35

G0 phase

Back 35

when the initials arrest the cycle due to environmental factors causing dormancy

Front 36

endoreduplication

Back 36

the continued DNA replication before a cell undergoes differentiation

Front 37

what is the purpose of endoreduplication?

Back 37

to increase the level of gene expression

Front 38

checkpoints

Back 38

crucial transition points in the cell cycle. Near the end of G1 and G2

Front 39

G1 phase

Back 39

increase in size, synthesis of more enzymes, ribosomes, organelles, membrane systems, and other cytoplasmic molecules and structures

Front 40

S phase

Back 40

(synthesis) histones are processed/synthesized

Front 41

G2 phase

Back 41

checks the chromosome replication is complete and any DNA damage is repaired

Front 42

centrioles

Back 42

(not in fungi and plants) formation of spindle fibers for separation of chromosomes

Front 43

centrosomes

Back 43

cloud surrounding centrioles

Front 44

what happens in a plant that doesn't happen in animal mitosis?

Back 44

the vacuole divides, the nucleus goes to the center and a cell plate forms for cytokinesis

Front 45

how is the nucleus anchored in the plant cell for mitosis?

Back 45

cytoplasmic strands

Front 46

phragmosome

Back 46

cytoplasmic strands that after anchoring the nucleus merge to form a sheet that bisects the plant cell.

Front 47

preprophase band

Back 47

dense band of microtubules encircling the nucleus on a plane corresponding to the equatorial plane of the future mitotic spindle appears during phase G2

Front 48

cell plate

Back 48

the initial partition between the daughter cells appearing in telophase

Front 49

how does the cell plate form?

Back 49

inside to the outside

Front 50

what is the order of the phases of mitosis

Back 50

prophase, metaphase, anaphase, telophase, cytokinesis

Front 51

prophase

Back 51

first stage of mitosis; chromatin condenses into chromosomes, chromatids align and bind together, and nuclear envelope disappears

Front 52

sister chromatids

Back 52

the initial and duplicated chromatin that "pair" together to make a chromosome

Front 53

centromere

Back 53

the region where the two sister chromatids are held together

Front 54

metaphase

Back 54

after prophase; chromatids are aligned in the center of the cell by microtubules

Front 55

mitotic spindle

Back 55

a 3-d structure that is widest in the middle and tapers towards its poles; appears where the nucleus was

Front 56

spindle fibers

Back 56

bundles of microtubules

Front 57

kinetochores

Back 57

spindle microtubules that become attached by protein complexes to either side of each chromosome

Front 58

kinetochore microtubules

Back 58

microtubules attached to the kinetochore

Front 59

polar microtubules

Back 59

spindle microtubules that extend from pole to pole and consists of two halves

Front 60

how are spindle fibers oriented?

Back 60

minus end at the poles and plus end pointing away from the pole

Front 61

anaphase

Back 61

after metaphase; the separation of the sister chromatids to opposite poles by the microtubules and at the centromeres are disconnected.

Front 62

daughter chromosomes

Back 62

separated sister chromatids

Front 63

how do the sister chromatids get moved to the poles?

Back 63

the center is dragged along by a motor protein on the spindle fiber and the end of the spindle fiber is shortened behind it.

Front 64

motor proteins

Back 64

use ATP to pull the chromosomes along the microtubules to the poles

Front 65

telophase

Back 65

final stage of mitosis; nuclear envelopes form, the spindle disappears, and the chromosomes elongate

Front 66

what is the longest stage of mitosis?

Back 66

prophase

Front 67

phragmoplast

Back 67

barrel shaped system of microtubules; overlapping microtubules; constructs the cell plate using vessicles

Front 68

are chromosomes different lengths

Back 68

yes

Front 69

chromatin

Back 69

the combination of DNA and its associated proteins

Front 70

what is chromatin mostly composed of?

Back 70

proteins

Front 71

histones

Back 71

positively charged, basic and attracted to DNA; synthesized in large amounts during S phase; folding and packaging of DNA

Front 72

nucleosomes

Back 72

the fundamental packing units of chromatin; core of 8 histones with DNA wrapped twice around

Front 73

RNA

Back 73

ribonucleic acid; half strand of DNA composed with ribose not deoxyribose

Front 74

where is RNA mostly found

Back 74

cytoplasm

Front 75

Path of DNA to proteins

Back 75

DNA>mRNA>tRNA>rRNA

Front 76

what is the template for mRNA

Back 76

DNA

Front 77

mRNA

Back 77

messenger RNA; synthesized from DNA strand through transcription; U replaces T; carries genetics to ribosomes

Front 78

RNA polymerase

Back 78

catalyzes the transcription of DNA to mRNA

Front 79

rRNA

Back 79

ribosomal RNA; composes ribosomes with proteins

Front 80

where does protein synthesis occur?

Back 80

ribosomes in the cytosol

Front 81

tRNA

Back 81

transfer RNA; molecules that are each specific for a particular amino acid

Front 82

translation

Back 82

the synthesis of a polypeptide directed by the nucleotide sequence of the mRNA

Front 83

replication

Back 83

the synthesis of an entire DNA molecule

Front 84

how many different amino acids are there?

Back 84

20 different amino acids

Front 85

genetic code

Back 85

DNA encodes for proteins (amino acids)

Front 86

codon

Back 86

a set of three nucleotides that sequence one amino acid

Front 87

promotor

Back 87

binding site for RNA polymerase and determine where transcription begins

Front 88

terminator

Back 88

a sequence that stops transcription

Front 89

anticodon

Back 89

a sequence of 3 nucleotides that binds to the codon on an mRNA molecule

Front 90

aminoacyl-tRNA

Back 90

a tRNA with an attached amino acid

Front 91

aminoacyl-tRNA synthetase

Back 91

connects the tRNA to its amino

Front 92

How many subunits does a ribosome have?

Back 92

2, one larger than the other

Front 93

mRNA-binding site

Back 93

binds the ribosome to the mRNA for transcription

Front 94

A site

Back 94

aminoacyl site; where the incoming amino binds

Front 95

P site

Back 95

(peptidyl) site; where the tRNA bearing the growing polypeptide chain resides

Front 96

E site

Back 96

exit site; from which the tRNAs leave the ribosome after they have released their amino acids

Front 97

translation

Back 97

initiation, elongation, termination

Front 98

initiation stage

Back 98

smaller ribosomal subunit attaches to mRNA near its 5' end and exposing the first codon, then larger subunit attaches and binds MET to A site

Front 99

elongation stage

Back 99

the second codon of mRNA is positioned opposite the vacant ribosomal A site, a tRNA binds to the mRNA and its amino acid occupies the A site of the ribosome. A peptide bond is formed between the two. The first tRNA is released via E site and returns to the cytosol

Front 100

peptidyl transferase

Back 100

activity of the larger ribosomal subunit forges a peptide bond between the two amino acids

Front 101

polysome/polyribosome

Back 101

a group of ribosomes translating the same mRNA strand

Front 102

termination stage

Back 102

when the ribosome gets to the stop codon and releases the mRNA

Front 103

stop codon

Back 103

stops translation at UAG, UAA or UGA

Front 104

what is so special about a stop codon in relation to the tRNA

Back 104

there are no tRNA that match the stop codon

Front 105

release factors

Back 105

cytoplasmic proteins that bind directly to a stop codon at the A site

Front 106

polypeptide/protein targeting and sorting

Back 106

attachment to the ER early on in the translational process. As the proteins are synthesized they are transferred across the membrane

Front 107

cotranslational import

Back 107

proteins are synthesized and transferred into or across a membrane

Front 108

how many cells does mitosis create?

Back 108

2 diploid cells

Front 109

how many cells does meiosis create?

Back 109

4 haploid cells

Front 110

zygote

Back 110

a gamete cell that unites with another gamete to produce a diploid cell

Front 111

spore

Back 111

a cell that can develop into an organism without another cell

Front 112

how do spores divide?

Back 112

mitotically to produce organisms that are haploid (gametes are produced through mitosis)

Front 113

stages of meiosis

Back 113

prophase 1, metaphase 1, anaphase 1, telophase 1, prophase 2, metaphase 2, anaphase 2, telophase 2, cytokinesis

Front 114

prophase 1

Back 114

chromosomes condense, homologous pairs form; crossing over occurs

Front 115

synapsis

Back 115

pairing of homologous chromosomes

Front 116

bivalents

Back 116

associated pairs of homologous chromosomes made of 4 chromatids

Front 117

synaptonemal complex

Back 117

unites the homologs

Front 118

crossing over

Back 118

during the time when then synaptonemal complex is existent, portions of the chromatids break apart and rejoin with corresponding segments from their homologous chromatids

Front 119

chiasma

Back 119

the x-like configuration where crossing over occurs

Front 120

metaphase 1

Back 120

the spindle appears, attaches to the centromeres and moves the paired (2) chromosomes to the middle (random assortment)

Front 121

anaphase 1

Back 121

homologous chromosomes are split apart and move towards the poles

Front 122

telophase 1

Back 122

the chromosomes relax, nuclear envelopes before, spindle disappears, nucleolus reforms

Front 123

prophase II

Back 123

chromosomes condense, nucleus disappears

Front 124

metaphase II

Back 124

spindle forms, sister chromatids line up in the middle

Front 125

anaphase II

Back 125

centromeres separate with the daughter chromosomes move to opposite poles

Front 126

telophase II

Back 126

nucleus forms and chromosomes relax (cytokinesis occurs afterwards)

Front 127

genetic recombination

Back 127

recombination of the genetic material from two parents

Front 128

mutation

Back 128

any change to the hereditary makeup of an organism

Front 129

chromosome mutations

Back 129

a piece may be deleted, duplicated, or inverted; # of chromosomes are altered

Front 130

point mutation

Back 130

only one or a few nucleotides are changed spontaneously or induced by mutagens (sometimes mispairings)

Front 131

mutagens

Back 131

agents that affect DNA; radiation

Front 132

deletions

Back 132

when segments of a chromosome are lost

Front 133

duplication

Back 133

when a segment of a chromosome is duplicated

Front 134

plasmids

Back 134

small circular molecules of DNA separate form the main chromosome, may reenter at places where they share sequences

Front 135

transposons

Back 135

genes that move as small segments of DNA

Front 136

position effects

Back 136

neighboring genes affect the transposon or vice versa

Front 137

inversion

Back 137

when two breaks in a chromosomal segment occur and the segment rotates 180 degrees and reattaches

Front 138

translocation

Back 138

a segment of DNA from one chromosome is exchanged with a segment from another, non homologous one

Front 139

aneuploidy

Back 139

the addition or subtraction of a chromosome

Front 140

polyploidy

Back 140

the duplication of whole sets of chromosomes

Front 141

how are mutations in haploid organisms vs diploid?

Back 141

the haploid mutations are immediately exposed to the surrounding environment (no dominant allele)

Front 142

heredity

Back 142

biological inheritance

Front 143

genetics

Back 143

the study of heredity

Front 144

sexual reproduction

Back 144

regular alternation between meiosis and fertilization

Front 145

meiosis

Back 145

the process of nuclear division in which the chromosome number is reduced from diploid (2n) to haploid (n). Two divisions=four cells with genetic diversity

Front 146

syngamy/fertilization

Back 146

the process by which two haploid cells (gametes) fuse to form a diploid zygote

Front 147

homologous chromosomes/homologs

Back 147

each chromosome has a partner that resembles it in size, shape, and heredity information

Front 148

allele

Back 148

one of two or more alternative forms of the same gene

Front 149

locus

Back 149

where alleles occupy the same space on homologous chromosomes

Front 150

dominant allele

Back 150

the only trait seen when crossing with a recessive trait; it completely covers the other trait

Front 151

recessive allele

Back 151

covered by the dominant trait and never shows in the F1 generation

Front 152

monohybrid

Back 152

cross between individuals that differ by one trait

Front 153

genotype

Back 153

genetic constitution or alleles present

Front 154

homozygous

Back 154

two of the same alleles

Front 155

heterozygous

Back 155

two different alleles present

Front 156

phenotype

Back 156

physical appearance caused by the genotype

Front 157

test cross

Back 157

the crossing of a homozygous dominant and homozygous recessive

Front 158

principle of segregation

Back 158

heredity characteristics are determined by discrete factors (genes) that appear in pairs; one inherited from each parent; meiosis separates the genes and passes them on (ALLELES OF ONE GENE)

Front 159

dihybrid

Back 159

the crossing of two individuals with two different traits

Front 160

principle of independent assortment

Back 160

the two alleles of a gene assort independently of other alleles (RELATIONSHIPS BETWEEN GENES)

Front 161

linked genes

Back 161

genes located closely together that are usually inherited together

Front 162

genetic/linkage maps

Back 162

provide an approximation of the positions of genes on chromosomes