Chapter 1 Flashcards
(104 cards)
1
Q
All living organisms share which common descent?
A
LUCA
(Last Universal Common Ancestor)
2
Q
What are the 3 domains? (Phylogenetic Tree of Life)
A
> Bacteria
Archaea
Eukaryota
3
Q
What are the 4 common themes for living organisms?
A
- Be seperate from their environment > lipid-based membrane
- Store info in a stable way > DNA & RNA
- Replicate & pass info to next generation > DNA replication
- Extract energy from surroundings > ATP (evolutionary conserved mechanisms)
4
Q
How are living organisms seperated from their enviroment? (Theme)
A
Lipid-based membrane
5
Q
How is information stored in a safe way? (Theme)
A
RNA & DNA
6
Q
How is energy extracted from surroundings? (Theme)
A
ATP (evolutionary conserved mechanisms)
7
Q
How is info passed to next generations? (Theme)
A
DNA Replication
8
Q
What are the 4 basic classes of Building Molecules?
A
> Nucleic Acids
Proteins
Lipids
Carbohydrates
9
Q
What are nucleic acids made of?
What are their function?
A
Nucleotides.
Store and carry information (DNA & RNA).
10
Q
What are proteins made of?
What are their function?
A
Amino acids.
Carry out cell’s function.
11
Q
What are lipids made of?
What are their function?
A
Fatty acids.
Form membranes around cells and organelles.
HYDROPHOBIC
12
Q
What are carbohydrates made of?
What are their function?
A
Small sugars.
Many roles - energy storage & solubility increase.
HYDROPHILIC
13
Q
What is DNA?
A
(Deoxyribonucleic acid) > Nucleic acid
How info is stored in a stable, heritable way
14
Q
What is DNA made up of? (4)
A
Nucleotides:
> (G) Deoxyguanosine monophosphate
> (A) Deoxyadenosine monophosphate
> (T) Deoxythymidine monophosphate
> (C) Deoxycytidine monophosphate
15
Q
What creates the info ‘code’ in DNA?
A
The order of the nucleotides (A, T, C, G)
16
Q
What is the structure of DNA?
A
Double helix with complementary nucleotides paired (A+T / C+G)
17
Q
Describe the double helix?
A
Directional > strands lie “head (5’) to toe (3’)
18
Q
What is a genome?
A
All the DNA sequences in an organism (aka the BLUEPRINT for its life)
19
Q
What is RNA and what is it used for?
A
(Ribonucleic acid) > Nucleic acid
Single-stranded, for information transfer
20
Q
What is the transmission of the genome? (3 “steps”)
A
- Accurate copying of info.
- Correct separation of copies.
- Transfer of copies into new cells.
21
Q
How is the integrity of genome transmission ensured?
A
Each step has several safety nets and checkpoints.
22
Q
What does the genome consist of?
A
Genes & Intergenic region
23
Q
What is a gene? And what parts (regions) does it consist of?
A
Region that controls a discrete hereditary characteristic (specific products like proteins & RNA)
Coding region + Regulatory region
24
Q
What info does a gene have?
A
For a product OR instructions for when/where a product is made.
25
True/False:
A single gene can code for many different products.
True
26
What is "Junk" DNA?
Does not encode a protein (non-genic) but is functional.
27
How is DNA packaged?
Linear/circular units called CHROMOSOMES.
28
What are chromosomes?
DNA packaged into linear/circular units.
29
How is DNA packaged efficiently in eukaryotes?
Wrapped round packing proteins (histones) and compacted = space efficient.
30
What are small extra pieces of DNA called?
Plasmids
31
What are plasmids?
Small extra pieces of DNA.
32
How can genomes vary? (3)
1. Size
2. Number of genes
3. Gene spacing
32
What does "genic" and "intergenic" mean?
Genic = encodes protein
Intergenic = does not encode protein
33
Explain how the amount of genes, genome size and increased genome complexity correlate with organisms of greater complexity? (single-celled vs multi-celled)
Single celled organisms have fewer genes than multicellular organisms.
BUT - genome size and complexity does not correlate with the organisms' complexity.
34
What are 'transposable elements' in genomes?
Pieces of DNA that copy themselves within a genome and increase genome genome size.
35
The 4 steps of Gene Expression:
1. Transcription (DNA gene)
2. RNA processing (rRNA, mRNA, tRNA)
3. Translation (protein)
4. Protein modification (various functions)
36
What is gene expression?
Turns genome information into products that carry out cellular functions (RNA or protein).
37
How is RNA made?
By copying the sequence of a region of the genome into a RNA molecule (transcription).
38
How is RNA used?
1. Used directly by cell.
2. Used as info to direct manufacture of a particular protein.
39
What is Transcription?
The copying of DNA into RNA molecules.
40
What is needed during transcription to synthesize RNA?
RNA polymerase
41
What is RNA polymerase used for?
To synthesize RNA.
41
Describe what happens during Transcription.
1. RNA polymerase synthesizes RNA.
2. DNA regions (initiator & terminator) signal RNA polymerase when to start/stop making RNA.
!! RNA does not contain thymidine > replaced by Uracil (U) !!
3. Coding RNA (mRNA) is then translated to protein while non-coding RNA isn't.
42
What are messenger RNAs (mRNA)?
Coding RNAs that contain the info to produce a protein.
43
What are coding RNAs that contain the info to produce a protein called?
mRNA > messenger RNA
44
How many amino acids are commonly used in proteins?
20 types of amino acids.
45
What is post-translational modification?
A chemical change that happens to a protein after it has been created by a ribosome.
> affect a protein's activity, location, and interactions with other proteins.
46
What is translation?
The process of turning the info in an mRNA into a protein.
47
What are the translation machinery? (4)
1. mRNA
2. Ribosome
3. tRNA
4. Amino acid
48
Where does translation begin/end?
Indicated by distinct sequences in the mRNA.
49
How is each amino acid encoded?
By 3 nucleotides in the mRNA molecule > CODON
50
What performs the translation?
Ribosome (has protein & RNA components)
51
What does transfer RNA (tRNA) do?
Interprets the info in mRNA into the protein sequence.
52
What is the start codon?
Methionine (AUG)
53
What are the stop codons? (3)
UAG
UGA
UAA
54
What is gene regulation responsible for?
Creating different types of cells within a multicellular organism.
55
Can identical genomes have different morphology and functions?
Yes, it has the same colection of genes but different proteomes (protein collection).
Ex. skeletal muscle cell, nerve cell & skin cell
56
Where is gene expression regulated?
All transcriptional and translational levels.
57
Key to gene regulation? (3)
Control of molecular synthesis, processing & degradation.
58
What can gene regulation determine?
Activities of different tissues.
Ex. Hy5 protein controling seedling height
59
How are genes regulated? (2)
1. Temporally (when)
2. Spatially (where)
60
Describe the genomes in prokaryotes.
Components of cells are spatially organized into regions (no internal membrane-bound compartments)
> Chromosomal DNA is in nucleoid region
> Non-specialized regions make up the cytoplasm
61
Where is chromosomal DNA found in prokaryotes?
Nucleoid region
62
What makes up the cytoplasm in prokaryites?
Non-specialized regions
63
Describe genomes in Eukaryotes.
Compartmentalization is very complex. (Membrane-bound regions)
> Chromosomes are found in nucleus
> Other membrane-bound regions (organelles) have distinct functions with their own genomes
64
What is the function of the Golgi apparatus and endoplasmic reticulum?
Protein production & processing.
65
Benefits of compartmentalization? (2)
1. Specialized functions confined to certain area.
2. Extra layers of possible regulation.
66
What produces the phenotype in organisms?
The activity and interplay of ALL GENES in a cell.
67
What is phenotype?
Visual features of an organism.
68
What is genotype?
Collective DNA sequence.
69
What is a ploidy?
Number of copies of its genome that an organism has.
70
Types of genomes? (3)
> Haploid (one genome copy)
> Diploid (two genome copies)
> Polyploid (many)
71
What is forward genetics?
Mutant phenotype is observed and then gene responsible identified (phenotype > genotype)
72
What is reverse genetics?
Gene is disrupted and then phenotype is observed (genotype > phenotype)
73
What are alleles?
Copies of a gene that are similar but different.
74
Different types of mutations? (2)
Recessive (wild-type gene can maintain function).
Dominant (wild-type gene cannot compensate for mutant gene).
75
Nature of mutations? (2)
1. Alter the sequence & structure of a protein.
2. Alter the regulatory regions of a gene = CHANGE EXPRESSION
76
What are null mutations?
Eliminate the function of a gene
77
What are missense mutations?
Single nucleotide changes that alter the encoded amino acid.
78
What are nonsense mutations?
Single nucleotide changes that introduce a premature stop codon.
79
What are silent mutations?
Single nucleotide changes that do not alter the encoded amino acid.
80
What are the 3 types of point mutations?
1. Missense mutation
2. Nonsense mutation
3. Silent mutation
81
What types of mutations can occur? (4)
1. Point mutation
2. Rearrangement
3. Deletion
4. Insertion
82
How can mutation only affect the organism vs the subsequent generations?
Only organism > mutation in SOMATIC CELLS
Generations > mutation in GERMLINE CELLS
83
What are monogenic diseases?
Caused by mutation in a single gene.
84
What are polygenic (multifactorial) diseases?
Caused by changes in several genes.
85
True/False
Mutation always causes diseases.
False.
It increase the likelihood of a disease.
86
What is penetrance?
The percentage of people with the mutation that will develop the disease.
87
Why are genomes ever changing?
Due to mutations in DNA.
88
What is Natural selection?
Allows the best-performing version (alleles) of a gene to persist in a population. (Most likely to reproduce).
89
How are new organisms produced (diversity increase) ?
Through cumulative mutations and natural selection = progressive changes.
90
What is DNA sequence comparison used for?
Identify similarity of DNA sequence to tell how related organisms are.
> genes for "core" processs more similar
91
What do we use to indicate relatedness?
Phylogenetic tree.
> Length of branch = how much related
92
Why are studies of model organisms important? (3)
> Allow research into and understanding of many biological processes.
> Allow to build hypotheses about how biological systems work.
> Allow comparisons to test whether hypotheses are generally applicable to diverse systems.
93
True/False:
All eukaryotes are multicellular
False.
All multicellular organisms are eukaryotes, but not all eukaryotes are multicellular.
94
Model organisms of fungi? (2)
Model organisms of bacteria? (2)
Fungi: S. pombe & S. cerevisiae
Bacteria: E. coli & B. subtilis
95
Model organisms to study fast generation time? (2)
1. Fruit fly (Drosophila melanogaster)
> distinct morphological features
> defect phenotypes are indicated in name
2. Nematode worm (Caenorthabditis elegans)
> simplicity
> pattern of cell division and fate are completely known
96
Model organisms to study morphological feature of develpment? (4)
1. African clawed frog (Xenopus laevis)
> large egg, easy to manipulate
2. House mouse (Mus musculus)
3. Zebrafish (Danio rerio)
4. Plant: Thale cress (Arabidopsis thaliana)
> short generation, small genome size, small for lab growth, many seeds
97
How are genomes in viruses stored?
Small nucleic acid genomes surrounded by protein coat.
98
Why do viruses need a host?
Cannot replicate on own, must use host's cellular machinery to produce more viruses within.
99
Which 2 viruses has been used as model organisms? and for what?
Lambda & Simian virus 40
> for understanding transcription & replication
100
Why are genes named differently in different organisms?
Due to historically different naming practices and independently discovered processes.
101
What are uppercase letters and italics used for in nomenclature?
Uppercase letters: Wild-type gene
Lowercase letters: Mutant gene
Italics: Gene
Non-italics: Protein produced by gene
102
