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Biology 103 > Everything up until the 2nd midterm > Flashcards

Everything up until the 2nd midterm Flashcards

1
Q

What is a cells metabolism?

A

The sum of chemical reactions in a cell. Some reactions releasing energy and some absorbing energy.

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2
Q

Anabolic pathways

A

BUILD polymers (molecules). They require energy to do this.

(happening within a cell)

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3
Q

Catabolic pathways

A

BREAK polymers (molecules). They release energy doing this.

(happening within a cell)

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4
Q

What are reactants?

A

The chemicals required in a chemical reactions.

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5
Q

What are products?

A

The chemicals produced in a chemical reactions.

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6
Q

What is Kinetic energy?

A

The movement of particles. (relates to heat/ temperature)

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7
Q

What is potential energy?

A

Stored energy. (relates to energy stored in matter). (eg. The energy required to hold chemical bonds together, otherwise known as chemical energy)

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8
Q

Exergonic reactions

A

RELEASE energy that have be stored in chemical bonds of the reactants.

Products have LESS stored energy than the reactants and free energy is produced.

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9
Q

Endergonic reactions

A

ABSORB energy and store it in the chemical bonds of the products as potential energy.

Products have MORE stored energy than the reactants.

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10
Q

What is Activation energy?

A

The energy that is required to initiate a chemical reactions.

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11
Q

What are Enzymes?

A

Proteins that catalyze (speed up) biochemical reactions by LOWERING the amount of activation energy required.

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12
Q

What is a substrate?

A

The molecule (reactant) that binds to the enzyme. (at the active site)

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13
Q

What is the Active site?

A

The special region of the enzyme where the substrate attaches to

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14
Q

What is DNA?

A

Deoxyribose Nucleic Acid.
A nucleic acid built from 2 parallel strands of nucleotide monomers.

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15
Q

What are the 3 parts of a nucleotide?

A

1) Five-carbon sugar
2) Phosphate group
3) Nitrogenous base

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16
Q

What are the 4 bases of DNA nucleotides

A

1) Adenine A
2) Thymine T
3) Guanine G
4) Cytosine C

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17
Q

Which bases form hydrogen bonds together?

A

Adenine pairs with Thymine (2 H bonds)

Guanine pairs with Cytosine (3 H bonds)

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18
Q

What shape is a DNA?

A

Double Helix

Each strand is complimentary and they act as Templates to build new strands

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19
Q

What is the backbone of DNA?

A

Sugars COVALENTLY bonded to phosphates

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20
Q

What is the “deoxyribose” part of DNA?

A

5-carbon sugar. Each carbon is labeled 1-5

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21
Q

The sugar of a nucleotide is covalently bonded to its phosphate group at which carbon?

A

5’

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22
Q

A nucleotide is covalently bonded to the next nucleotide at which carbon?

A

3’

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23
Q

Why is DNA “anti-parallel”?

A

One strand runs 5-3 and the other runs 3-5

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24
Q

What are the “rungs” of the DNA ladder?

A

The 4 nitrogenous bases. ATGC

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25
Q

Why is cellular division essential to life for single celled and multicellular organisms?

A

Single celled:
Cellular division is a form of creating new life (reproduction)
Multicellular:
Cellular division allows for growth in size, increased complexity, and repair

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26
Q

Describe asexual reproduction in mitotic division

A

Identical sister chromatids are separated, resulting in the formation of two identical daughter nuclei
-mitosis is the nuclear division stage
-cytokinesis is the stage in which the cells physically separate

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27
Q

What are the four phases of mitosis?

A

-Prophase (early and late)
-Metaphase
-Anaphase
-Telophase

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28
Q

What is interphase and cellular division? (simple answers)

A

Interphase = growing and developing
Cellular division = reproduction

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29
Q

Explain interphase and the 3 distinct intervals

A

Interphase is the longest phase of a cell’s life (80-90%) and is where the cell grows, develops, and completes its typical tasks.

Three distinct intervals:
-G1 Phase (first gap)
-S Phase (DNA synthesis)
-G2 Phase (second gap)

  • see slide 4 for a picture demonstrating this
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30
Q

What does DNA look like in interphase? (mitosis)

A

DNA is uncondensed in interphase in a form called chromatin; used for protein synthesis
-chromatin looks foggy within a cell’s nucleus - nucleolus visible as dark patch

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31
Q

What is G0 phase?

A

-Not all cells will divide immediately. some will exit the cell cycle after G1 and will not immediately undergo cellular division
-These cells will enter G0 phase
-Some cells remain in G0 permanently, others only for a few days

“resting phase”

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32
Q

Explain S phase (mitosis)

A

-If a cell does continue to S phase, their DNA (chromosomes) will be duplicated
-Newly formed and identical chromosomes will be attached at the centromere
-Chromosomes are now called sister chromatids

*see slide 8 for before/after S phase

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33
Q

What happens in G2 of interphase? (mitosis)

A

The cytoskeleton breaks down and the centrioles duplicate

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34
Q

What happens in early prophase? (mitosis)

A

-nucleolus disappears (no more need for ribosomes)
-chromatin condenses, chromatids visible
-spindle fibres form from centrioles, pushing them apart

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35
Q

What happens in late prophase? (mitosis)

A

-the nuclear membrane breaks down
-centrioles are at opposite ends of the cell
-spindle fibres connect with centromeres of chromatids

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36
Q

Explain interphase vs prophase (mitosis)

A

interphase: clear nucleolus, fuzzy chromatin in nucleus (90% of cells at this stage in any given moment)
prophase: no nucleolus, clear chromatid strands (sometimes not bound within nucleus)

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37
Q

What happens in metaphase? (mitosis)

A

-spindle fibres have pulled the chromatids into an organized line across the metaphase plate along the center of the cell
*spindle checkpoint - enzymes ensure all chromosomes are lined up and properly connected to spindle fibres before continuing

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38
Q

What happens in anaphase? (mitosis)

A

-spindle fibres shorten to pull the sister chromatids apart, each toward opposite ends
-cell visibly elongates
-sister chromatids are now considered to be daughter chromosomes

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39
Q

What happens in telophase (mitosis)

A

-chromosomes decondense back into chromatin; spindle fibres break down
-two new nuclear membranes and nucleoli reappear
-now two complete daughter nuclei in one cell

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40
Q

What happens in cytokinesis (mitosis)

A

-cell splits into two identical daughter cells
-in animal cells, plasma membrane pinches together to form cleavage furrow to separate nuclei
-in plant cells, a cell plate forms between cell walls
*see slide 19 for visual

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41
Q

What is the difference between plant cell and animal cell cytokinesis (mitosis)

A

-in animal cells, plasma membrane pinches together to form cleavage furrow to separate nuclei
-in plant cells, a cell plate forms between cell walls
*see slide 19 for visual

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42
Q

What are checkpoints in mitosis for?

A

-Cells will not divide if certain checkpoints are not met
-regulatory proteins check for errors, inadequacies
-ensures that cell division only takes place if the cell is healthy

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43
Q

What are the three checkpoints? What do they check for?

A

G1 checkpoint: nutrients, growth factors, DNA damage
-some cells will exit after G1 into G0

G2 checkpoint: cell size, DNA replication

Metaphase checkpoint: chromosome spindle attachment

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44
Q

What happens if checkpoints don’t work properly? How does this relate to cancer?

A

-mutations in DNA may cause regulatory proteins to misfold and skip the replication checkpoints
-damaged cells may divide without control
-cells that rapidly divide become abnormal and do not function properly. They can form masses called tumors.

-if these unregulated cells invade other tissues, they are considered cancer cells
-they can metastasize (spread) via circulatory system to form new tumors

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45
Q

What does meiosis produce? Sexual or asexual?

A

Produces sex cells
mitosis = asexual
meiosis = sexual - plants also do this
-meiosis is a specialized type of cell division that results in gametes (sex cells; sperm and egg cells) that have half the number of chromosomes

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46
Q

What is sexual reproduction?

A

The combination of genetic information form two parents to create unique offspring

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47
Q

What are gametes?

A

Sex cells
-they have one set of each chromosome, thus are considered haploid (n)
-n=the number of unique chromosomes of that species

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48
Q

What is fertilization? What is a zygote?

A

The fusion of two gametes, which results in a unique zygote that has two sets of each chromosome
haploid sperm + haploid egg = diploid zygote
n + n = 2n

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49
Q

What are somatic cells?

A

They are human body cells, and are diploid (2n)
Each set of chromosomes is considered a homologous pair
-human somatic cells are 2n=46
-human gametes are n=23
-human somatic cells are 2n=46

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50
Q

Meiosis results in haploid gametes
idk how to put this one into a question just click to the answer lol

A

-meiosis is the cellular division process that results in genetically unique haploid gametes
-meiosis involves one round of DNA replication (interphase) and two rounds of cell division (meiosis 1 and meiosis 2)

look at slide 6

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51
Q

What is crossing over?

A

-to create change/variation
-non sister chromatids exchange genetic material
-sister chromatids are no linger identical to each other
-1st source of genetic variation produced by meiosis

This also seems to be what recombinant chromosomes are? Idk she asked about it in the learning outcomes but I cant find it anywhere in notes or slides. Heres online definition:
the exchange of genetic material either between multiple chromosomes or between different regions of the same chromosome.

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52
Q

What happens in metaphase 1?

A

-homologous chromosomes will line up at metaphase plate in groups called tetrads
-orientation of the pair is completely random, adding to genetic variability

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53
Q

What are tetrads? When do they form?

A

Tetrads are 2 forms of chromatids
They form in metaphase 1

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54
Q

What happens in anaphase 1?

A

Homologous chromosomes are pulled to opposite poles by spindle fibers
-sister chromatids are still connected to each other at centromeres
Either chromosome may be pulled towards either end of the cell
-called independent assortment
-2nd form of genetic variation in meiosis

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55
Q

What is independent assortment? When does it occur?

A

It is when either chromosome may be pulled towards either end of the cell
-2nd form of genetic variation in meiosis

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56
Q

What happens in telophase 1?

A

-one sister chromatid set from each homologous pair is now at each pole of the cell
-cytokinesis usually occurs at the same time, forming two haploid daughter cells
*chromosomes are still duplicated in this form (two un-identical sister chromatids still attached at centromeres)

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57
Q

List and describe 3 factors that increase genetic variation in offspring through meiosis and fertilization

A

-crossing over - non-sister chromatids exchange genetic material (the process of exchanging)
-independent assortment - either chromosome may be pulled towards either end of the cell
-recombinant chromosomes = the results of crossing over (you now have 2 unique chromosomes)

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58
Q

What is interkinesis?

A

-the stage between meiosis 1 and 2
-cells continue to grow
-DNA does NOT replicate (no S phase)

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59
Q

What is the difference between interkinesis and interphase?

A

interphase duplicates DNA, interkinesis does not
-both happen before division

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60
Q

What happens in prophase 2?

A

If nuclear membrane is present, it breaks down and chromosomes re-condense

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61
Q

What happens in metaphase 2?

A

Chromosomes form a single line across the middle of the cell (just like regular metaphase, but now for haploid cells)

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62
Q

What happens in anaphase 2?

A

-sister chromatids are separated and move to opposite poles
-once separated, each sister is now considered a chromosome

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63
Q

What happens in telophase 2

A

Nuclear membrane forms around each set of chromosomes

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64
Q

What are the big differences between stages of mitosis, meiosis 1, and meiosis 2?

A

Mitosis:
-asexual
-one round of cell division
Meiosis 1:
meiosis has 2 rounds of cell division
sexual

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65
Q

What is cytokinesis?

A

-daughter cells separate
-one from each of the two from meiosis 1, for a total of four daughter cells
-cells are all haploid (n)
-cells are all unique to each other due to crossing over (prophase 1) and independent assortment (anaphase 1)

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66
Q

What is spermatogenesis?

A

The creation of sperm cells
-one diploid spermatocyte will divide equally into four haploid spermatids
-all four spermatids may develop into sperm cells
-this process occurs continuously in testes from puberty

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67
Q

What is a cell’s metabolism?

A

the sum of the chemical reactions taking place inside of a cell

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68
Q

What is an anabolic pathway?

A

Small molecules (monomers) are assembled into large ones(polymers). Energy is required.

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69
Q

what is a catabolic pathway?

A

Large molecules (polymers) are broken down into smaller ones, Energy is released.

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70
Q

How are chemical reactions written?

A

Reactants -> Products

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71
Q

What is oogenesis?

A

The creation of egg cells
-one diploid oocyte will only give rise to one viable haploid egg cell
-during meiosis 1, one haploid cell will get most of the cytoplasm and organelles
-meiosis 1 is oaused in early prophase following embryonic development, doesn’t continue until puberty
-when an egg is released during the menstrual cycle, it is paused in meiosis 2
-if fertilized by a sperm, meiosis 2 will complete and the unequal division will occur again, leaving one viable egg cell and another smaller polar body, which will disintegrate

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72
Q

What are reactants?

A

the chemicals required in a chemical reaction

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73
Q

What are products?

A

the chemicals produced in a chemical reaction

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74
Q

What is kinetic energy?

A

the movement of particles, relating to heat and temperature

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75
Q

What is potential energy?

A

Stored energy, relating to energy stored in matter

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76
Q

What is energy?

A

the ability to do work, it can be in different forms, for example, chemical bonds (AKA chemical energy)

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77
Q

What are exergonic reactions?

A

they release energy that has been stored in chemical bonds of reactants. Products have less stored energy than reactants and free energy is produced

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78
Q

What are endergonic reactions?

A

they absorb energy and store it in chemical bonds of the products as potential energy
- Products have more stored energy than reactants

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79
Q

What is activation energy?

A

In all chemical reactions, this energy (activation energy) input is required

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80
Q

What are enzymes?

A

enzymes are proteins that catalyze (speed up) biochemical reactions by lowering the activation energy required

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81
Q

What is a substrate?

A

a chemical reactant that the enzyme binds to at a special region called its active site (forms an enzyme-substrate complex)

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82
Q

what is the active site of an enzyme?

A

the special region that substrates bind to

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83
Q

How do enzymes speed up chemical reactions?

A

physically bringing reactants together, compromising bond structures in reactants, taking part in the reaction itself

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84
Q

What happens to an enzyme once the reaction is finished?

A

the enzyme remains unchanged and may continue to catalyze more reactions

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85
Q

What part of an enzyme will impact its function?

A

Its shape (quaternary structure)

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86
Q

What happens if an enzyme is misfolded?

A

its active site will not allow for substrates to bind

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87
Q

How does the body regulate enzyme activity?

A

changing the temperature and/or pH of environment

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88
Q

Explain how enzymes have an optimal pH for activity

A

the concentration of H+ in a solution can change the chemical bonds in a protein’s amino acid change (enzymes have specific optimal pH ranges)

A change in the active site of an enzyme leads to a change in the enzymes activity

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89
Q

What happens to an enzyme if it denatures?

A

if the bonds in a protein are broken down too severely, the protein denatures, and cannot bind to its substrate

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90
Q

How does an enzyme denature?

A

too high temperature, or out of optimal pH range

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91
Q

What is an inhibitor?

A

a molecule that can bind to enzymes to block or reduce action

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92
Q

What is a competetive inhibitor?

A

an inhibitor that binds directly to enzymes active site, blocking binding of substrate completely

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93
Q

what is a non-competitive inhibitor?

A

an inhibitor that binds to an enzyme in the allosteric site, reducing rate of reaction

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94
Q

What is the difference between spermatogenesis and oogenesis? How many, and what X or Y chromosomes are donated by the zygote?

A

Spermatogenesis:
-diploid spermatocyte will divide equally into four haploid spermatids
spermatocyte dides equally into four haploid spermatids
process occurs continuously in testes from puberty
Oogenesis:
-one oocyte will only give rise to one viable haploid egg cell
-one haploid cell will get most of the cytoplasm and organelles
-meiosis 1 is paused in early prophase, doesn’t continue till puberty

Sperm carry X or Y
Eggs always carry X
36 from each

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95
Q

What is penicillin?

A

a compound produced by fungi, a competitive inhibitor for bacterial enzyme used to create cell walls, and it is used as an antibiotic to treat bacterial infections

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96
Q

How do anabolic and catabolic reactions relate to exergonic and endergonic reactions?

A

catabolic reactions are exergonic; anabolic reactions are endergonic

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97
Q

How do enzymes impact the energy required for biological reactions?

A

enzymes lower activation energy

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98
Q

Name three ways we can modify an enzyme’s action by changing its shape

A

pH, temperature, inhibitor

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99
Q

What is ATP?

A

adenosine triphosphate, it is a useable form of energy

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100
Q

What is cellular respiration?

A
  • a series of cellular enzymatic reactions that collects the stored energy from glucose molecules
  • The free energy collected is then stored in a more useable form, ATP
  • ATP is considered the “energy currency” of the cell and is used for various cellular processes
  • cells convert ADP TO ATP, using the energy stored in glucose molecules to do so
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101
Q

what is the chemical formula for cellular respiration?

A

C6 H12 O6 + 6O2 —–> 6CO2 + 6H2O + ATP

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102
Q

What is stored between phosphates of ATP?

A

energy

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103
Q

what is ATP composed of?

A

1 adenine (nitrogenous base)
1 ribose sugar
3 phosphates

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104
Q

what is between the second and third phosphate in an ATP molecule?

A

a very high energy bond (easy to break)
- hydrolysis releases the energy

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105
Q

Why does it take so much energy to attach the second and third phosphates in ATP?

A

2 negative ions don’t want to attach, thee third is forced onto the second. In cellular respiration, hydrolysis releases the energy stored in between the 2nd and 3rd phosphate

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106
Q

What is the molecule ATP called after the third phosphate is removed?

A

ADP - adenosine diphosphate

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107
Q

What are the two main steps that are involved in protein synthesis?

A

Transcription & Translation

108
Q

What is glucose?

A

an organic (carbon and hydrogen-containing) molecule with many strong covalent bonds - a large amount of energy is stored within the covalent bonds between the carbons

109
Q

How many ATP can a single molecule of glucose produce?

A

32-38 ATP via cellular respiration

110
Q

What are the three steps of cellular respiration

A
  1. Glycolysis
  2. Citric Acid Cycle
  3. Electron Transport CHain
111
Q

What happens in the first step of cellular respiration?

A

Glycolysis = breaking glucose

In glycolysis, a 6-carbon glucose molecule is split in two (breaking down the covalent bonds between carbons)
- Two 3-carbon pyruvate molecules are the products
- This step takes place in the cytoplasm of the cell
- No mitochondria needed
- No oxygen needed

Starting with CARBON -> ending with pyruvates (2)

112
Q

What type of cells can do glycolysis?

A

eukaryotes and prokaryotes

113
Q

How much ATP does glycolysis start with and result in?

A

2 ATP required for initial reaction, by the end, 4 ATP are newly synthesized

THUS: net gain of 2 ATP
So, cells without mitochondria can still create ATP

114
Q

How many NADH molecules does glycolysis create?

A

2 NADH

115
Q

What is NADH?

A

the reduced form of the molecule NAD+ after it has accepted two electrons and a proton (which together are the equivalent of a hydrogen atom with an extra electron).

116
Q

what does NADH do?

A

stores high energy electrons

117
Q

what happens to NAD+ during glycolysis?

A

molecules called NAD+ receive a hydrogen ion and two electrons, converting them to NADH. These high energy electrons are then shuttled to the mitochondria

NAD+ + H+ + 2e- -> NADH

118
Q

WHat is the process of transferring high energy electrons?

A

oxidation-reduction (redox) reaction

119
Q

What are the reactants of glycolysis?

A

1 Glucose molecule + 2 ATP + 2 NAD+

120
Q

What is transcription

A

the copying of a DNA segment

121
Q

what are the products of glycolysis?

A

2 pyruvates + 4 ATP + 2 NADH

122
Q

What is Translation?

A

building a protein from a genetic code.

123
Q

What is the oxidized form of the electron carrier?

A

NAD+

124
Q

what is the reduced form of the electron carrier?

A

NADH

125
Q

What is the difference between NAD+ and NADH?

A

the nitrogenous base in NADH has one more hydrogen ion and two more electrons than in NAD+

126
Q

How is RNA unique from DNA? (3 things)

A
  • ribose sugar (instead of deoxyribose)
  • Has the base of uracil (U) instead of thymine(T)
  • RNA is single stranded
127
Q

What is the second step of cellular respiration?

A

the citric acid cycle (AKA krebs cycle)

128
Q

What are the three types of RNA used in protein synthesis?

A
  • messenger RNA (mRNA)
  • ribosomal RNA (rRNA)
  • transfer RNA (tRNA)
129
Q

What happens during the citric acid cycle?

A

pyruvates are broken down. If oxygen is available the pyruvates are transferred into the mitochondria of the cell to be further broken down. The pyruvates are allowed to go down the concentration gradient, then shuttled into the mitochondria, fro, the cytoplasm into the mitochondrion

130
Q

How many membranes do the mitochondria have?

A

two membranes - a double membrane

131
Q

what is the job of messenger RNA?

A

Contains the genetic code from a DNA template, is sent to ribosomes for translation

Specifies the order of amino acids in a protein using a series of 3-base codons, where different amino acids are specified by particular codons..

132
Q

what is the job of ribosomal RNA?

A
  • is found in the ribosomes and is used to bind to animo acids together.
  • assists in making the covalent bonds that link amino acids together to make a protein.
133
Q

How do the pyruvates break down?

A

before the cycle begins, a carbon from the pyruvate molecule is removed and joined with oxygen to form CO2, which leaves the cell. The newly formed 2-carbon acetyl group is picked up by a carrier compound called coenzyme A to form acetyl CoA. (everytime a carbon is taken off, the enzyme will attach itself where the carbon was).

134
Q

What is the main job of transfer RNA?

A

carries amino acids and brings them to the ribosome for protein synthesis

  • transports the correct amino acids to the ribosome using the information encoded in the mRNA
135
Q

How does the formation of acetyl CoA also form NADH?

A

as pyruvate is broken and joined with Coenzyme A, two electrons are donated to another NAD+ to form NADH. The newly formed acetyl CoA molecule then enters the citric acid cycle. Reminder: this happens twice (one glucose molecule; two pyruvates)

136
Q

How many times is the pyruvate broken down and joined with coenzyme A?

A

twice.

137
Q

What are the three steps of transcription?

A

1) Initiation
2) Elongation
3) Termination

138
Q

How does the citric acid cycle break Acetyl groups?

A
  • acetyl-CoA undergoes a series of chemical reactions which further break the molecules apart
  • As the molecules are broken, high energy electrons are donated to 3 NAD + and 1 FAD (another electron carrier)
  • 2 more CO2 are formed
  • 1 ATP is created
  • Coenzyme A gets reused, and brought back to the preparatory step
139
Q

How does the process of creating a protein first kick off?

A

a particular gene in the DNA code will be TRANSCRIBED into messenger RNA (mRNA), which can then LEAVE the nucleus.

140
Q

WHat are the reactants of the citric acid cycle?

A

IN: 2 acetyl groups + 6 NAD+ + 2 FAD

141
Q

What are the products of the citric acid cycle?

A

OUT: 4 CO2 + 6 NADH + 2 FADH2 + 2 ATP

142
Q

What is non-disjunction?

A

-occurs in meiosis
- if pieces of chromosomes are lost, duplicated, or improperly moved within a chromosome to another, this results in non-disjunction
-results in differences in the genetics of the egg and sperm cells
*not the same at genetic mutation

143
Q

what are the three regions of a gene that can code for proteins?

A

1) PROMOTER region = used to initiate transcription
location - upstream of the gene, on one side.

2) RNA-coding region = the thing that is transcribed
location - middle of the gene

3) TERMINATOR region = ends the transcription
location - downstream of the gene

144
Q

what are the different components of a mitochondria membrane?

A

outer membrane, inner membrane

the space between these membranes is the intermembrance space

the space beneath the inner membrane is called the mitochondrial matrix

2 membranes

145
Q

what is the third step in cellular respiration?

A

Electron Transport Chain

146
Q

What can non-disjunction result in?

A

-down syndrome
three copies of chromosome 21, aka trisomy 21
-turner syndrome
only one sex chromosome (X)

147
Q

How does the promoter region of a gene INITIATE transcription?

A
  • RNA POLYMERASE (enzyme) binds to the gene at the PROMOTER region…
  • the job of RNA polymerase is to pull apart the strands and lay down an RNA strand opposite of the DNA template strand.
148
Q

What happens in the electron transport chain?

A

the final step takes place at the inner mitochondrial membrane. This inner membrane has multiple specialized protein channels. These proteins will take part in the electron transport chain, which will be used to create an electrochemical gradient

NADH and FADH2 donate high energy electrons to protein complexes within the inner mitochondrial membrane, which push H+ up their gradient into the intermembrane space

149
Q

What are similarities between sexual and asexual reproduction?

A

difference:
sexual: combination of genetic info from two parents = unique offspring
asexual:
only one organism required, creates clone-not unique
*not done, brain died lol

150
Q

how does RNA polymerase ELONGATE the mRNA strand?

A
  • when attached to the DNA template strand creates the mRNA strand in a 5’ to 3’ direction
  • literally produces RNA molecule

5’ - 3’ is inverse the DNA template

151
Q

if the DNA template was: 3’ A A G T 5’ what would the mRNA stand be?

A

5’ U U C A 3’

152
Q

How does H+ get actively transported through the electron transport chain?

A

NADH and FADH2 pass their electrons to the protein channels, which pass them on to the next channel in series. As the electrons get passed, they lose energy. This energy is used to actively transport hydrogen ions into the intermembrane space to form a gradient (building up concentration gradient)

153
Q

What happens at the end of the electron transport chain?

A

in the final protein complex, the low energy electrons are accepted by oxygen (called the terminal acceptor), the oxygen with its extra electrons combines with two hydrogen ions to form water (H2O)

154
Q

What happens when the electron transport chain forms electrochemical gradient?

A
  • Once enough H + (protons) have been pumped into the intermembrane space, there is a strong electrochemical gradient (proton gradient):
  • High [H +] in the intermembrane space
  • Low [H +] in the mitochondrial matrix
  • The protons want to passively travel DOWN their gradient
155
Q

What is chemiosmosis?

A

It forms ATP via ATP synthase.

156
Q

What is ATP synthaze?

A

an enyzme embedded on the inner membrane and allows these H+ to pass

157
Q

How does RNA polymerase TERMINATE transcription?

A
  • when the gene is fully transcribed and RNA polymerase it will reach the TERMINATOR REGION of the gene.
  • terminator region = sequence of repeating nucleotides
    (e.g. A A A A A ….)

– this stalls the RNA polymerase, it stalls and falls off the DNA strand. (can’t do its job so it falls off)

158
Q

What does the electrochemical gradient cause?

A

due to this strong gradient, the H+ want to passively move back into the matrix. ATP synthase is an enzyme embedded on the inner membrane and allows these H+ ions to pass. As H+ travel through ATP synthase back into the matrix via chemiosmosis, ATP is synthesized.

159
Q

What step forms 90% of ATP from cellular respiration?

A

chemiosmosis

160
Q

what are the reactants in the electron transport chain/ATP synthase?

A

IN: - Electrons from NADH and FADH2 , O2 and H+

161
Q

what are the products in the electron transport chain/ATP synthase?

A

OUT: 6 H2O and ~30 ATP

162
Q

What does the mitochondrion do?

A

uses cellular respiration meaning the cell converts chemical energy in the from of glucose to cellular energy also known as ATP

163
Q

What is fermentation?

A

Anaerobic Respiration.

If no oxygen is available, fermentation may occur in the cytoplasm of a cell. Fermentation is the anaerobic (no oxygen) way to continuously create ATP from glucose
- Recall: Glycolysis creates 2 ATP!

164
Q

What is the main purpose of fermentation?

A

to revert the 2 NADH back to NAD+ for reuse in future glycolysis steps. The pyruvates from glycolysis are converted into either lactate or ethanol

165
Q

How are DNA polymerase and RNA polymerase different?

A

DNA polymerase:
- makes double stranded molecule

RNA polymerase:
- makes single stranded molecule

(we might want to add to this? idk)

166
Q

What occurs to glucose in glycolysis?

A

a 6-carbon glucose molecule is split in two: 3-carbon pyruvate molecules

167
Q

What do NADH carry with them?

A

high energy electrons

167
Q

Where does the citric acid cycle take place in a cell?

A

the mitochondria

168
Q

What particle gets pushed against their concentration gradient into the intermembrane space?

A

H+

169
Q

What enzyme creates ATP as these particles move back into the matrix?

A

ATP synthase

170
Q

How is the complimentary DNA strand made in DNA replication different from the mRNA template strand made in transcription?

A

DNA complementary strand:
- uses deoxyribose sugar
- uses thymine

mRNA template strand:
- uses ribose sugar
- uses Uracil

(nucleotide thymine is replaced with uracil in RNA template strands)

  • might also want to add to this later?
171
Q

How is mRNA modified before leaving the nucleus?

A

1) mRNA stabilizing proteins are added.
2) 5’ recognition caps are added to the the 5’ end
3) Poly-A tails will be added to the 3’ ends
4) mRNA gets spliced

172
Q

describe the process and goal of ‘splicing’ mRNA

A

process:
gene is initially transcribed into “pre-mRNA’ (bolded term)

pre-mRNA gets transcribed into 2 parts: exons and introns

goal:
we want to keep the EXONS and translate those bits into proteins…
we want to remove the INTRONS

pre-mRNA will have its introns removed (this process is called SPLICING) –> this creates the mature mRNA molecule

173
Q

After the process of ‘splicing’, where does the mRNA go?

describe how this transportation occurs.

A

the mature mRNA leaves the nucleus and is brought to ribosomes.

it is shuttled through the NUCLEAR PORES of the NUCLEAR MEMBRANE and to the ribosomes.

174
Q

what are the ribosomes responsible for in protein synthesis?

A
  • the translation step.
  • mRNA is translated into a string of amino acids.
175
Q

describe the process of TRANSLATION.

where does it occur & what does it create

A

occurs in ribosomes & it creates polypeptides…

how you might ask?

  • mRNA strand arrives at the ribosome.
  • string of mRNA nucleotides will be read in groups of 3 (called CODONS)
  • each codon is TRANSLATED into a specific amino acid
    (aka protein / polypeptide)
176
Q

Can multiple codons translate to the same amino acid?

A

hell ya

177
Q

what is a start codon?

A

codons that code for the start of translation

178
Q

what is a stop codon?

A

codons that code for the end of translation

179
Q

In translation - what happens in the INITIATION step?

A

1) mRNA cap & tail guide the mRNA to bind to small ribosomal subunit
2) start codon is read
3) ribosomes are assembled

180
Q

In translation - what happens in the ELONGATION step?

A

1) mRNA codons are read
2) amino acids are added in a sequence - forming a polypeptide chain
3) tRNA brings the specific amino acids to the ribosome for assembly

181
Q

tRNA is a special little guy.

why is his job important in the elongation step?

A
  • tRNA molecules have an amino acid at one and an ANTICODON region at the other.
  • if the ANTICODON on the tRNA matches up with the CODON on the mRNA then it will add its amino acid to the chain.

the anticodon looks like a little bar scanner, and its like yup you got the right bar code, so I’m gonna give you my amino acid.

182
Q

In translation - what happens in the TERMINATION step?

A
  • stop codon read
  • polypeptide is completed and freed
  • ribosome dissociates
183
Q

if the DNA template strand reads
3’ T A C G A G C T A 5’
what will the mRNA strand be?

A

complimentary DNA strand: 5’ A T G C T C G A T 3’
mRNA strand. : 5’ A U G C U C G A U 3’

if you had the chart could you tell me what the amino acid sequence would be?

184
Q

Learning Outcome:
What are the two major steps of protein synthesis?
Where do they occur?
What form is the “code” in? (DNA, RNA, or amino acids)?

A

major steps: transcription + translation

transcription occurs in the nucleus.
translation occurs at the site of ribosomes. (so probably mostly @ the rough ER)

code = amino acids (I think???)

185
Q

Learning Outcome:

What are the similarities and differences between RNA and DNA in terms of their structure?

A

RNA:
- Uracil
- Ribose sugar
- Single stranded molecule
- short

Same:
- have nitrogenous bases
- have sugar-phosphate backbone

DNA:
- Thymine
- Deoxyribose sugar
- double-stranded molecule
- long

186
Q

Learning Outcome:

what are the three major types of RNA involved in protein synthesis?

what are their roles?

A

1) mRNA
- carries protein information from the nucleus to the ribosomes.
- dictates the order that amino acids should be added to a protein

2) rRNA
- found in ribosome
- binds amino acids together with covalent bonds

3) tRNA
- carries amino acids to the protein for synthesis

187
Q

Learning Outcome:
what are the main steps of transcription?
what happens in each step?
what are the structures involved?

A

1) Initiation
- RNA polymerase pulls apart DNA strands and lays down RNA strands

2) Elongation
- RNA polymerase attaches to template strand.
- starts creating mRNA strand 5’ to 3’

3) Termination
- When fully transcribed RNA polymerase reaches the terminator region
- polymerase dissociates and falls off the DNA strand.

Structures involved: RNA polymerase

188
Q

Learning Outcome:
- Describe how eukaryotic mRNA is processed before its shuttled into the cytoplasm.. (what 4 modifications occur?)

A

1) mRNA stabeling proteins added
2) 5’ recognition caps added
3) Poly- A tails added
4) mRNA is spliced to remove Introns

189
Q

Learning Outcome:
describe the different steps in translation and know the important structures and players involved (what is a codon? tRNA? Anticodon?)

A

1) Initiation (start codon read, ribsosomes assembled)
2) Elongation (amino acids added in sequence)
3) Termination (stop codon read, ribosome dissociates)

1 codon = 3 bases = 1 amino acid
tRNA = carries amino acid
anticodon = bases to match mRNA template
(anticodon = 3’ to 5’) (mRNA = 5’ to 3’)

190
Q

LO:
Be able to determine the amino acid sequence from an mRNA strand, or even from a DNA strand

A

just practice

191
Q

LO:
Describe the genetic code and how the nucleotide sequence determines the amino acid and the protein sequence

A

………………………

192
Q

Define: mutation

A

a permanent change in a DNA sequence

193
Q

what may mutations result in?

A
  • differences in the amino acid sequence
  • major physiological / anatomical changes in an organism
194
Q

what is an example an anatomical change produced by a mutation?

A

sickle cell anemia (reduced oxygen capacity in red blood cells)

195
Q

What are the two major ways that a mutation can arise?

A

1) spontaneous error
2) Environmental mutagens

196
Q

when does a spontaneous error occur?

A

durring DNA replication

197
Q

What is meant by an environmental mutagen?

A

factors that cause mutagens

198
Q

What is a silent mutation?

A

when the mutation results in the same amino acid being produced…

there is no observable change to the protein

(many mRNA codons can code for the same amino acid, so sometimes if one base gets mutated its not a big deal)

199
Q

What is a NONSENSE mutation?

A

when a mutation leads to a stop codon

  • amino acid sequence will stop being synthesized
  • this could lead to a missing or dysfunctional protein (depending on where this took place in the animo acid chain)
200
Q

what is a MISSENSE mutation?

A

when the mutation leads to a shift in the mRNA codons

e.g. a deletion of a base

since the codons are read in triplets, this causes a domino effect of all of the bases downstream to shift

produces entirely different animo acids

201
Q

What is a POINT mutation?

A

when only one or two nucleotides are effected

202
Q

what are the three types of point mutations?

A

1) substitution
2) deletion
3) insertion

203
Q

what is a point substitution mutation?

A

one base is substituted for another.

typically, only 1 codon is effected in these types of mutation…

it may lead to a SILENT or NONSENSE mutation.

204
Q

What is an example of a point substitution mutation?

A

sickle cell anemia

  • caused by single base change
  • leads to single animo acid change
205
Q

what is a point deletion mutation?

A

when one or more bases are deleted

leads to frameshift in the codon sequence…
amino acids get fucked
its a MISSENSE MUTATION

206
Q

What is an example of a point deletion mutation?

A

cystic fibrosis

  • deletion results in protein channel misfolding and becoming dysfunctional
  • leads to mucus build up in tissues and physiological challenges
207
Q

what is a point insert mutation?

A

when one or more bases are added to the code

  • leads to missense mutation
  • everything gets shifted down.
  • results in different amino acids being created
208
Q

What is an example of a point insertion mutation?

A

Huntington’s disease

  • brain cells are damaged by misshapen proteins
  • over time, individuals lose co-ordination of movements, cognitive function, and memory
209
Q

Can mutations be chromosomal?

A

yes

sometimes large sections of the chromosomes are modified

210
Q

what is chromosomal deletion?

A

when large segments of DNA are lost

211
Q

Chromosomal Mutations: What is duplication?

A

when segments of DNA are repeated

212
Q

Chromosomal Mutations: what are inversions?

A

segments of DNA break off and flip 180 degrees

213
Q

Chromosomal Mutations: what are translocations?

A

segments move from one chromosome to another (non-homologous)

214
Q

What is an example of an inversion mutation?

A

hemophilia

  • blood clotting disorder
  • nucleotides are the same, but in a different order on the chromosome.
  • proteins are different…. its bad
215
Q

what happens when a mutation occurs in somatic cells?

A

it may affect the individual BUT the mutation is not based on to offspring

216
Q

what happens when a mutation occurs in germ cells?

A
  • germ cells = egg / sperm cells
  • they may be inherited by offspring
  • these mutations drive evolution, as they are passed down to the next generation
217
Q

What is gene therapy?

A

the introduction, removal, or change in the genetic material

e.g. replacing defective genes with healthy ones + adding new genes to help the body fight or treat diseases

218
Q

when can gene therapy be used?

A

when there is no drug or surgery option for treatment or cure for a disease

219
Q

what are vectors?

A

in gene therapy, vectors deliver the genes into cells.

can be IN VIVO - into patients themselves
or EX VIVO - cells removed, genes added, cells returned

220
Q

Concept Check:
if the DNA codon was TTC, what would the mRNA codon be?
what amino acid would that lead to?
What would an example of a silent mutation be to the DNA codon?

A

Comp DNA : AAG
mRNA codon: AAG
amino acid: Lys
silent mutation (same amino acid): AAA
translate back to DNA: TTT

221
Q

Concept Check: Nonsense Mutation

If a genetic codon was ATA, what would the mRNA codon be?
what amino acid would this lead to?
what would be an example of a nonsense mutation to the DNA codon?

A

Comp DNA: TAT
mRNA codon: UAU
amino acid: Tyr
nonsense mutation (aka stop codon): UAA
back to DNA: TAA
——> ATT

222
Q

Concept Check: Missense Mutation

consider the transcription and translation of the following genetic code:
DNA 3’ ATA GCC TCA 5’
mRNA 5’ UAU CGG AGU 3’
AA Tyr Agr Ser

How would each change if the first A was deleted in DNA?

A

DNA 3’ TAG CCT CA 5’
mRNA 5’ AUC GGA GU 3’
AA. Lle Gly stop

(need to see the wheel thing to know this)

223
Q

Concept Check: Mutation Types
if the genetic code was ATG CCT TAC

a. What type of chromosomal mutation would lead to…
i. ATG CCT TAC ATG CCT TAC ATG CCT TAC
ii.
iii. ATG TTA ATA CGC CTT TAC
iv. CAT TCC GTA

b. What type of point mutation would lead to…
i. AAG CCT TAC
ii. ATT GCC TTA C
iii. ATG CTT AC

A

a. chromosomal:
i. duplication
ii. deletion
iii. translocation
iv. inversion

b. point mutation
i. substitution
ii. insertion
iii. deletion

224
Q

What are genetic traits?

A

inherited qualities received from parent(s)

225
Q

what are invariant traits?
give example

A

invariant traits are the same in all individuals of a species
(they don’t vary)
e.g. all humans have two eyes, same bones, ect

226
Q

what are variable traits?

A

variable traits may differ among individuals
(they vary)
e.g. different eye colours, height, ect

227
Q

What are genes?

A

stretches of DNA on a CHROMOSOME that contain codes for particular traits

228
Q

what are ALLELES?

A

different versions of a given gene

for example (pea plants can have either purple or white flowers)

229
Q

What happens if an allele is dominant?

A
  • it is always expressed if present
  • it represses other genes

e.g. purple allele represses white allele for flower colour gene. (because the purple allele is dominant)

230
Q

How are dominant alleles represented?

A

with CAPITAL LETTERS

e.g. P represents purple allele

231
Q

when are RECESSIVE ALLELES expressed?

A

ONLY in the absence of dominant alleles

e.g. white flowers will only be white if there is no purple allele present

232
Q

how are recessive alleles represented?

A

with a lowercase letter

e.g. ‘p’ represents white alleles

233
Q

what is a GENOTYPE?

A

the specific combination of alleles that an individual possesses for a particular gene.

e.g. for flower colour, pea plants could be PP, Pp, or pp

its just all the combinations possible of gene expression

234
Q

what is a PHENOTYPE?

A

the physical expression of those alleles

e.g. pea plants that are PP or Pp will still have purple flowers, and pea plants that are pp will have white flowers

235
Q

how many alleles do diploid cells have?

A

two!

a diploid organism inherits two alleles, one from each parental gamete

236
Q

when is an organism considered HOMOZYGOUS?

A

when both alleles are the same

e.g. PP or pp

GAY

237
Q

when is an organism considered HETEROZYGOUS?

A

when the alleles are different

e.g. Pp

NOT GAY

238
Q

Concept Check:

  • Consider the three following genotypes:
    AA Aa aa
    1. Which genotypes are homozygous?
    2. Which genotypes are heterozygous?
    3. If the A allele codes for tall pea plants and the a allele codes for short pea plants, which plants will have the tall phenotype?
    4. Which plants will have the short phenotype?
    5. Which allele is dominant?
A
  1. AA aa —- they gay
  2. Aa —- straight
  3. tall = AA and Aa
  4. short = aa
  5. A is dominant
239
Q

How do gametes pass on their alleles to future generations?

A
  1. alleles separate from each other during the production of gametes (MEIOSIS)
  2. gametes carry 1 allele
  3. gametes have EQUAL LIKELYHOOD of passing on either allele to future generations
240
Q

What are PUNNET SQUARES used for?

A
  • they are used to predict genetic probabilities in future generations
  • reveals all potential offspring genotypes and phenotypes!
  • a grid is used to map out the possible parental allele combinations
241
Q

if the genotype of both parents are Pp, what are the possible combinations of genes that might be produced in offspring?

A

PP, Pp, Pp, pp

242
Q

how do you create a punnet square?

A

2 x 2 table.

  • 2 paternal (from sperm) alleles ABOVE each column
  • maternal (from egg) alleles TO THE LEFT of each row
  • create 4 allele combinations.
  • important: dominant allele always comes first when writing out the combinations (Pp)
  • the combinations = the potential GENOTYPES of the next generation
243
Q

how do you determine the GENOTYPE RATIO of a punnet square?

how is this expressed?

A
  • you count how many out of the 4 have each possible genotype.
  • stated as either a percentage or a fraction

e.g. if the possible genotypes are PP, Pp, Pp, pp
the ratio:
PP = 1/4
Pp = 2/4
pp = 1/4

percentage:
PP = 25%
Pp = 50%
pp = 25%

244
Q

how do you determine the GENOTYPE RATIO?

A

count how many of the four have each possible phenotype

(e.g. how many flowers will be purple and white based on the dominant allele)
P = dominant = purple
p = recessive = white

so if we are working with PP, Pp, Pp, pp

ratio:
3/4 will be purple
1/4 will be white

percentage:
75% purple
25% white

245
Q

What is meant by ‘Heterozygotes can be carriers’?

A

Heterozygous individuals can carry a trait in their genotype and not express it (but they might pass it on)

many atypical genetic conditions are recessive.
(e.g. deafness / sickle cell anemia / cystic fibrosis)

in order to express these conditions, an individual must have both recessive alleles in their genotype (e.g. ‘pp’)

246
Q

Carrier Punnet Square Practice:

  • A heterozygous hearing female (Dd) has a child with
    a deaf male (dd). What is the probability the child
    will be deaf?
  • Hint: make a Punnett Square and see how many
    offspring will be dd
A

results: Dd, Dd, dd, dd

probability child will be deaf: 50%

247
Q

What is a PEDIGREE CHART?

A

demonstrate the patterns of inheritance of a particular trait passed down a family line

248
Q

NEED TO LOOK AT PEDIGREE CHARTS CAUSE WUT.

A

video posted on D2L / slides reference idk

249
Q

Who is Rosalind Franklin?

A

Chemist in the 1950s.
worked at kings university
Took and studied X-ray photos of DNA to determine their structure. Published her findings in 1953

250
Q

Who was James Watson and Francis Crick?

A

Douchebags. Their boy “Maurice Wilkins” leaked them info on Rosalind’s findings and they stole that shit and then got a noble prize for it and then wrote a book that admitted to all of it while also bullying her in the process.

251
Q

When does DNA replicate?

A

In the S phase of interphase

252
Q

Why is DNA replication considered a “Semi-conservative process”?

A

Because when it unzips each strand is used for a template of new strands to attach to

253
Q

What are the 3 major phases (steps) in DNA replication?

A

1) Initiation (breaking of hydrogen bonds)

2) Elongation (building new strands)

3) Termination (sealing new strands)

254
Q

Where does the 1st step (initation) happen on DNA?

A

Origin sites! there are thousands of them

255
Q

What enzyme participates in the initiation phase of DNA replication and what does it do and where?

A

DNA HELICASE ENZYME.
It breaks the hydrogen bonds at the origin sites and travels in opposite directions.

256
Q

What are replication forks?

A

When Helicase starts to unzip the DNA in opposite directions and it looks like 2 Y shape paths.(–<>–)

257
Q

In the 2nd step of DNA replication what is need to form new complimentary strands?

A

Primase enzyme will add RNA PRIMERS to the newly exposed DNA

258
Q

What does DNA polymerase do in the 2nd step of replication?

A

It initiates DNA synthesis at the primers.
Adds nucleotides in the 5-3 direction. only one strand is continuously doing this and its called the leading strand

259
Q

How is the Lagging strand formed?

A

“Okazaki fragments”.
later connected by DNA LIGASE (3rd step)

260
Q

How are the Okazaki fragments of the lagging strand linked?

A

Ligase enzyme

261
Q

2 identical copies of DNA are attached at the…..?

A

CENTROMERE!

262
Q

What do each of the following enzymes do during DNA replication?
1) Helicase
2) Primase
3) Polymerase
4) Ligase

CC

A

1) break hydrogen bonds (unwinds the DNA)

2) adds RNA primers at newly exposed strands

3) initiatives DNA synthesis at eh primers

4) joins together the newly synthesized DNA in a seamless strand (zips the zipper back up)

263
Q

What are Telomeres?

A

little caps at the ends of the chromosomes to protect the loss of important genetic information.

non-coding strands of bases that will progressively get shorter after each DNAreplication

264
Q

What happens to telomeres that get too short?

A

Trigger an entrance to G0 to protect daughter cells from loss of genetic information

cell will no longer divide

265
Q

What is telomerase and what does it do?

A

An enzyme that synthesizes telomere regions.

Cells will not “age” if they have telomerase because their genetic material will be safe from destruction.

These proteins are found in germ cells, stem cells, and some cancer cells

Biology 103 (5 decks)

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