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post midterm stuff Flashcards

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1
Q

what is the principle of dominance?

A

In a heterozygote, one allele may conceal the presence of another

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2
Q

what is the principle of segregation?

A

in a heterozygote, 2 different alleles segregate during the formation of gametes

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3
Q

homozygote

A

the same, diploid individual has 2 copies of the same allele

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4
Q

heterozygote

A

different, diploid individual has 2 different alleles of the same gene

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5
Q

true breeding

A

breeding where the parents would produce offspring with the same phenotype

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6
Q

cross-fertilization

A

fertilize a plant using pollen from another plant of the same series

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7
Q

monohybrid

A

mono meaning one, hybrid is the offspring of 2 organisms from different species, ex. TT x tt

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8
Q

filial

A

son or daughter

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9
Q

ex. of a genotype

A

AA homozygous dominant

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10
Q

ex. of a phenotype

A

blue eyes

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11
Q

what is the S phase of the cell cycle?

A

DNA replication, making genetic copies of the cell before they divide to ensure each new cell receives the right amount of chromosomes

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12
Q

what is transcription?

A

the process of copying a segment of DNA into RNA

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13
Q

what is translation?

A

where a genetic code from a strand of mRNA is decoded to produce a particular sequence of amino acids, takes place on ribosomes

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14
Q

what is genotype in molecular biology?

A

typically the DNA sequence that codes for an RNA

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15
Q

what is a phenotype in molecular biology?

A

typically the action of the corresponding RNA or protein

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16
Q

what is the principle of independent assortment?

A

the alleles of different genes segregate or assort independently of one another

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17
Q

what biological process explains segregation and independent assortment?

A

meiosis

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18
Q

what is incomplete dominance?

A

the phenotype in a heterozygote is a mix or in the middle between the phenotype of the two homozygotes ex. red flower + white flower = pink flower

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19
Q

what is codominance?

A

both alleles show phenotypes in a heterozygote ex. white cow + brown cow = white and brown cow

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20
Q

ABO glycosyltransferase in the cell becomes what and where?

A

becomes a red blood cell in the bone marrow

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21
Q

what is epistasis?

A

an allele of one gene hides the effects of alleles of another gene- homozygous recessive phenotype
of one gene (e) overrides both
dominant (B) and recessive (b)
alleles of the other gene.

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22
Q

what is pleiotropy?

A

one gene controls the expression of several phenotypic traits, ex. sickle cell anemia allele causes 2 different phenotypes- sickle cell disease and resistance to malaria

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23
Q

why would it be a “bell-shaped curve”?

A

continuous variation in a natural population as opposed to discontinuous variation (having many independent small effects leads to a bell)- also called normal distribution

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24
Q

meiosis?

A

each gamete receives only one copy (chromatid) from each homologous pair of chromosomes, as a result gametes are haploid

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25
Q

diploid?

A

having 2 complete sets of chromosomes one from each parent

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26
Q

haploid?

A

having a single set of unpaired chromosomes

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27
Q

which structure is not a part of the nucleus?

A

nucleoid

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28
Q

what is it called when a population has more than 2 alleles of a gene?

A

multiple genes

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29
Q

what is polygenic inheritance?

A

alleles of multiple genes have additive effects on a quantitative trait

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30
Q

if the 2 genes are on the same chromosome then why do recombinants appear at all?

A

genes that are on the same chromosome travel through meiosis together, however alleles of chromosomally linked can be recombined by crossing over

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31
Q

how do you get new combinations of previously existing genetic material?

A

independent assortment of chromosomes in meiosis OR crossing over of homologous chromatids in meiosis

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32
Q

what is the site of crossing over called?

A

chiasma

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33
Q

what generates the most recombination?

A

independent assortment of chromosomes

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34
Q

what does the physical distance between alleles on the same chromosome dictate?

A

it dictates the probability of crossing over happening between 2 loci, a measure of genetic distance between alleles

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35
Q

what is synaptonemal complex?

A

a protein structure that forms between 2 homologous chromosomes in meiosis thought to mediate synapsis and recombination (meiosis 1 in eukaryotes)

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36
Q

what is the difference between eukaryotes and prokaryotes?

A

eukaryotes have a nucleus, mitochondria, and other organelles; prokaryotes have no organelles except ribosomes

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37
Q

what are the similarities between eukaryotes and prokaryotes?

A

both have DNA, cell wall, plasma membrane, and ribosomes

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38
Q

what is the maximum frequency of recombinants and why?

A

50%, independent assortment and any number of crossovers yields 50% recombinant gametes

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39
Q

how do you count recombinant and nonrecombinant chromosomes?

A

a test cross

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40
Q

what chromosome do females lack?

A

Y chromosome

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41
Q

in humans what gene determines sex and where is it?

A

the SRY gene, it is located on the Y chromosome

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42
Q

what does the testis-determining factor (TDF) determine?

A

causes the gonad to develop as a testis instead of an ovary

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43
Q

what are the chromosomes and symptoms of Klinefelter syndrome?

A

male XXY, low testosterone and infertile

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44
Q

what are the chromosomes and symptoms of turner syndrome?

A

female XO, missing X chromosome, short neck, wide chest,

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45
Q

are most people with red-green color blindness male or female, why?

A

male, because they only have 1 X chromosome so if it is passed down they will be affected

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46
Q

what are pedigrees used for?

A

to determine dominant and recessive traits in human families, assess the probability of receiving those traits

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47
Q

what is hemophilia?

A

uncontrolled bleeding due to a defect in one of the proteins needed for blood clotting

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48
Q

what is chromatin made of?

A

nucleic acid + proteins

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49
Q

what is a bacteriophage?

A

a virus that infects bacteria

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50
Q

what element is found in DNA and not protein?

A

phosphorous

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51
Q

what element is found in protein but not DNA?

A

sulfur

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52
Q

in the covalent structure of DNA what are the bases called?

A

purine (AG) and pyrimidines (CT)

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53
Q

what are the 3 hypothetical DNA replication mechanisms?

A

semi-conservative, conservative, and dispersive

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54
Q

what does topoisomerase do during DNA replication?

A

prevents twisting as DNA unwinds and rejoins the DNA strands

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55
Q

how does the cell prevent 2 separated strands from snapping back together again?

A

the complementary base pairs zipper the 2 strands together by hydrogen bonding

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56
Q

what do single-stranded binding proteins do in DNA replication?

A

they coat each separated strand, preventing them from coming back together

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57
Q

what does a cell need to do in order to make a copy of its DNA?

A

that primase adds nucleo8des to the RNA primer at the 3ʹ′
end. Once the primer is completed, primase detaches, and a
DNA synthesizing enzyme, DNA polymerase III, a<aches to the
exposed 3ʹ′ end of the RNA primer.
What does a cell need to do, in
order to make a copy of its DNA?
Note that the primer is an8parallel to the parental template strand.

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57
Q

what does a cell need to do in order to make a copy of its DNA?

A

the primase adds nucleotide to the RNA primer at the 3’ end, when the primer is completed the primase detaches and DNA polymerase III attaches to the exposed 3’ end of the RNA primer

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58
Q

what does a sliding clamp do?

A

prevents DNA polymerase from falling off prematurely

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59
Q

how does DNA polymerase do once attached to the 3’ end of the RNA primer?

A

it extends the daughter strand by adding complementary DNA nucleotides on the strand in the 5’ to 3’ direction

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60
Q

why does one the RNA primers face the wrong way?

A

because the 2 DNA strand run in opposite direction (antiparallel)

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61
Q

DNA polymerase III synthesizes DNA away from the replication fork producing _______?

A

producing a short piece of DNA called and Okazaki fragment

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62
Q

what does DNA polymerase I do?

A

extends the Okazaki fragment, removing ribonucleotides of the RNA primer and replacing them with deoxyribonucleotides

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63
Q

what enzyme is needed to repair the nick left by DNA polymerase I?

A

DNA ligase

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64
Q

what is helicase?

A

the unzipping enzyme in DNA replication

65
Q

what do DNA polymerase need to replicate DNA?

A

dNTPs, a primer nucleic acid with free 3’-OH, template DNA to specify the sequence of a new strand

66
Q

where is the replication origin (single) for small circular chromosomes?

A

most prokaryotes, mitochondria, chloroplasts

67
Q

where is the replication origin (multiple) for linear and large chromosomes?

A

nuclear genomes of practically all eukaryotes

68
Q

how do genes produce the traits we observe in an organism’s phenotype?

A

DNA codes for RNA - transcription
RNA codes for proteins - translation
proteins (don’t code for DNA or RNA) the activity of the RNA and proteins produce observed phenotypes

69
Q

what is gene expression?

A

the process when the nucleotide sequence of a gene directs protein synthesis to produce the structures of the cell

70
Q

where does transcription occur in prokaryotes?

A

cytoplasm

71
Q

where does transcription occur in eukaryotes?

A

nucleus

72
Q

transcription of a gene occurs in what 3 stages?

A

initiation, elongation, and termination

73
Q

in the initiation of transcription, a gene consists of what?

A

a promoter and a transcription unit

74
Q

the combination of what forms the transcription initiation complex?

A

the combination of transcription factors and RNA ploymerase

75
Q

in prokaryotes how do transcription and translation happen together?

A

mRNAs are translated by ribosomes, while the mRNAs are still being transcribed by RNA polymerase

76
Q

eukaryote mRNAs must go through processing in the nucleus before they are ready to leave the nucleus, what is the mRNA called before and after processing?

A

the initial mRNA is called a PREcursor mRNA and after processing the mRNAs are called mature mRNAs

77
Q

what is the guanine cap used for in mRNA processing in eukaryotes?

A

a guanine cap is added to the 5’ end of a pre-mRNA by a capping enzyme while the mRNA is still be transcribed by the nucleus

78
Q

what are the 3 things a guanine cap does?

A

1) protects mRNAs from degradation by RNA exonucleases once the mRNAs enter the cytosol
2) facilitates the transport of mRNAs from the nucleus out through the nuclear pores, into the cytosol
3)the site where ribosomes attach to the mRNA a the beginning of the translation in the cytosol

79
Q

once the pre-mRNA is fully transcribed what does poly(A) polymerase add?

A

the enzyme adds a chain of 50-250 adenine nucleotides one at a time to the 3’ end of each pre-mRNA

80
Q

what is the poly (A) tail important for?

A

1) nuclear export
2) facilitating transportation
3) the length of the tail can determine how many times an mRNA is translated before it is enzymatically degraded in the cytosol by the RNA exonucleases

81
Q

how are introns removed from pre-mRNAs?

A

introns are spliced out of the mRNA and the exons are connected together (introns are excluded from mature-mRNAs)

82
Q

what is messenger RNA - mRNA?

A

a long polynucleotide strand possessing the code for a particular polypeptide chain on it

83
Q

what is a codon?

A

it is 3 nucleotide bases in length and most codons code for a particular amino acid that is to be added to a polypeptide chain

84
Q

what is transfer RNA (tRNA)?

A

adaptors to match amino acids to mRNA sequences. they have a covalently attached amino acid and a corresponding anticodon

85
Q

what is ribosomal RNA (rRNA)?

A

part of the structure of the ribosome, the factory that makes proteins

86
Q

what does the start codon (AUG) do?

A

starts translation and also codes for the amino acid methionine

87
Q

what do stop codons do?

A

they stop translation, they do not code for any amino acid

88
Q

why is the genetic code said to be degenerate?

A

18 of the amino acids are coded for by more than one codon

89
Q

why is the genetic code said to be universal?

A

almost all living things use an identical genetic code

90
Q

what is the adaptor hypothesis?

A

adaptor molecules linked to amino acids contain an anti-codon that can base pair with mRNA

91
Q

what is an aminoacyl-­‐tRNA synthetase?

A

an enzyme in the cytosol that adds the correct amino acid to the tRNA with the appropriate anticodon

92
Q

in eukaryotes, ribosomal subunits are made from what and where?

A

made from rRNAs and proteins in the nucleolus of the nucleus, then they leave the nucleus and become functional in the cytoplasm

93
Q

some polypeptides form a functional protein by themselves, what can be said about the genes?

A

just one gene has to be expressed to produce these proteins

94
Q

some polypeptides are joined with other different polypeptides in order to form a functional protein, what can be said about the genes?

A

2 or more different genes must be expressed to produce this functional protein

95
Q

What produces the phenotypic expression of the gene?

A

the functional protein

96
Q

how many genes and polypeptide chains does myoglobin have?

A

1 polypeptide chain and 1 gene

97
Q

how many polypeptide chains and genes does a hemoglobin have?

A

4 polypeptide chains and 2 genes

98
Q

what is post-translational modification?

A

after proteins leave the ribosome they are folded are modified in some way

99
Q

what are the 3 producers of genetic variation?

A

1) mutations
2) independent assortment
3) recombination

100
Q

what is missense mutation?

A

a single base substitution can change the meaning of a codon, often alter after protein function, can be neutral

101
Q

what is a frameshift mutation?

A

an insertion or deletion can disrupt the reading frame

102
Q

what are silent mutations?

A

usually, neutral mutations that do not have an observable effect on the phenotype

103
Q

what are nonsense mutations?

A

premature stop codon usually result in inactive or absent protein

104
Q

what is the usual result of a frameshift?

A

a nonfunctional protein

105
Q

what are the things genes can code for?

A

enzymes, proteins, and polypeptides, and any kind of RNA

106
Q

what is the main energy currency of the cell?

A

ATP

107
Q

what is cellular respiration?

A

a process that cells use to get energy from food molecules usually with oxygen, energy found in ATP

108
Q

what is substrate-level phosphorylation and where does it occur?

A

where a phosphate group is transferred from a substrate to ADP and occurs in the cytoplasm and mitochondria

109
Q

what is oxidative phosphorylation and where does it occur?

A

uses the energy released from the electron transport chain to generate ATP, occurs on the inner membrane of the mitochondria

110
Q

what are anabolic pathways?

A

use energy to build complex molecules from simpler ones ex. photosynthesis and synthesis of macromolecules

111
Q

what are catabolic pathways?

A

release energy by the breakdown of complex molecules into simple compounds ex. energy extracted from the breakdown of glucose

112
Q

where is glycolysis found?

A

most bacteria, archaea, and eukaryotes

113
Q

what are the stages of glycolysis?

A

energy investment, cleavage, energy payoff

114
Q

what happens during energy investment?

A

2 ATP molecules are used to phosphorylate the original glucose making it more reactive

115
Q

what is lactate fermentation?

A

in animals, pyruvate, when it is reduced, is converted to lactate

116
Q

what is alcoholic fermentation?

A

in brewing yeast, anaerobic reduction of pyruvate leads to alcohol formation in 2 steps- pyruvate to acetaldehyde then acetaldehyde to ethanol

117
Q

when cells sustain glycolysis by fermentation ATP is only available from what?

A

substrate-level phosphorylation

118
Q

what is an aerobes lifestyle?

A

many archaea, bacteria, and eukaryotes need O2 to survive and are unable to live solely by fermentation

119
Q

what is a facultative anaerobes lifestyle?

A

able to switch between fermentation and anaerobic respiration relying on the availability of O2

120
Q

what is an obligate anaerobes lifestyle?

A

requires an O2 free environment to survive gaining ATP from fermentation or anaerobic respiration

121
Q

where do heterotrophs get their energy?

A

from other living things

122
Q

where do autotrophs get their energy?

A

from abiotic sources ex. the sun

123
Q

what is glycolysis?

A

breaking glucose into two 3 carbon molecules, in the cytosol, doesn’t use oxygen

124
Q

what is cellular respiration?

A

oxidizing fuels to release energy, which happens in mitochondria or plasma membrane, requires O2 and energy from glucose

125
Q

what is the difference between reduction and oxidation?

A

reduction is the gain of an electron, oxidation is the loss of an electron

126
Q

what are redox reactions?

A

the transfer of electrons between molecules or atoms and consists of an oxidation, reduction, and 2 half reactions

127
Q

why is a hydrogen atom often added to the reduced molecule?

A

to neutralize the charge of the electron received and lost from the oxidized molecule

128
Q

what is the function of the inner-mitochondrial membrane?

A

electron transfer and ATP synthesis by ATP synthase

129
Q

what is the function of the mitochondrial matrix?

A

reactions removing electrons from fuel molecules (pyruvate oxidation, citric acid cycle)

130
Q

to enter the Krebs/citric acid cycle what must the pyruvate do?

A

pyruvate must first be converted to acetyl-CoA

131
Q

pyruvate passes through what to get to the Krebs cycle?

A

passes through the mitochondrial membranes and then into the matrix before the Krebs cycle

132
Q

how does acetyl-CoA enter the Krebs cycle?

A

acetyl-CoA is combined with a molecule oxaloacetate to form a molecule of citrate

133
Q

what are respiratory electron transport chains and where are they located?

A

they are located on the folded inner membrane of the mitochondrion (cristae) they are a series of exergonic redox reactions involving a series of electron acceptor molecules

134
Q

what is chemiosmosis?

A

the return of H+ to the matrix due to the electric field and difference in concentration

135
Q

what is aerobic respiration?

A

reactions that transfer energy from O2 and organic nutrients to ATP while releasing waste products CO2 and H2O

136
Q

where does the electron transport chain pump hydrogen ions and what is the result?

A

pumps them from the matrix into the intermembrane space this results in a separation of charges

137
Q

can a difference in solute concentration be used as a source of energy?

A

YESSSSS

138
Q

what is photosynthesis?

A

energy from light, stored as organic carbon compounds and an electron acceptor (almost always O2)

139
Q

what are the 2 criteria used to classify something as a living thing?

A

their carbon source and their energy source

140
Q

what two ways can organisms obtain carbon?

A

autotrophs- able to carry out carbon fixation using CO2 as a carbon source “primary producers” and heterotrophs- feed on organic matter produced by other organisms, unable to produce their own carbon compounds

141
Q

what is the difference between phototrophs and chemotrophs?

A

phototrophs use light as an energy source and chemotrophs use the oxidation of reduced compounds from the environment as an energy source

142
Q

what are some examples of photoautotrophs?

A

plants, algae, cyanobacteria, various oddball creatures

143
Q

what are the thylakoid membranes called grana for?

A

they are the green colored membranes that harvest light

144
Q

what are the 2 sets of reactions that photosynthesis consists of?

A

light reactions- the light-driven production of ATP and NADPH AND carbon fixation- the conversion of CO2 to carbs

145
Q

why are plants green?

A

chloroplasts absorb the light (blue and red) to use the energy

146
Q

what is a photosystem?

A

a large complex of proteins and pigments in the chloroplast thylakoid membrane, containing a reaction center and antenna complexes

147
Q

what are antenna complexes?

A

organized units where chlorophyll molecules in the thylakoid membrane are associated with being chlorophyll-binding proteins

148
Q

where does the antenna complex transfer light energy?

A

into the reaction center

149
Q

what is the reaction center?

A

a complex of chlorophyll a molecules and proteins, and the primary electron acceptor

150
Q

what do the antenna complexes do?

A

they are the main light-harvesting systems, they contain lots of chlorophyll and other pigments like carotenoids. they transfer light energy to the reaction centers of photosystem II and photosystem I

151
Q

what is the function of photosystem II?

A

splitting of water to get electrons, steals electrons from water making O2 (photolysis)

152
Q

what is the function of photosystem I?

A

reduces NADP to NADPH

153
Q

what is a similarity between both photosystems?

A

both are able to feed high energy electrons into electron transport chains

154
Q

what is the purpose of the Calvin cycle?

A

to make glucose and other organic compounds

155
Q

what is the most abundant enzyme on earth?

A

rubisco

156
Q

what is mesophyll?

A

the main photosynthetic cell type in vascular land plants

157
Q

what is the stomata?

A

pores that can open and close

158
Q

what are the molecules of the 3-phosphoglycerate used for?

A

most of the molecules are used to continue the Calvin cycle while the rest are available to make glucose

159
Q

how do enzymes catalyze reactions?

A

they lower the activation energy required

160
Q

what factors can denature an enzyme?

A

temperature and pH

161
Q

how would a cell transport a fully translated protein through it’s plasma membrane?

A

endocytosis or exocytosis

Biology 120 (2 decks)

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