Biology 1 Flashcards
(323 cards)
1
Q
Who proposed the cell theory?
A
Matthias Scheiden and Theodor Schwann
2
Q
What are the postulates of the cell theory?
A
All living things are made of cells
Cell is the basic functional unit of life
Chemical reactions of life take place inside the cell
Cells come from pre-existing cells
Cells carry genetic info in the form of DNA, which is passed from parent to daughter cell
3
Q
What are the 6 kingdoms?
A
Bacteria, Archaea, Protista, Fungi, Plantae, and Animalia
4
Q
What are the 2 major types of cells?
A
Prokaryotic and eukaryotic
5
Q
What do ALL prokaryotes contain?
A
Cell membrane, cytoplasm, genetic material and ribosomes
6
Q
What kingdom got split into 2?
A
Monera split into bacteria and Archaea because they had differing origins
7
Q
What does the fluid mosaic model propose?
A
Cell membrane made of phospholipid belayer with proteins embedded throughout
8
Q
How can the fluidity of the cell membrane be adjusted?
A
The cell can regulate the fluidity of its membrane by adjusting the amount of unsaturated hydrocarbon tails present in the membrane. The unsaturated hydrocarbon tails are “bent”, and thus do not pack together as closely as saturated hydrocarbon tails. Animal cells can also regulate the fluidity of the cell membrane by adjusting the amount of cholesterol present in the membrane
9
Q
What are the parts of phospholipid molecules?
A
Phospholipid molecules have hydrophobic (non polar) fatty chains of carbon and hydrogen and phosphorus containing hydrophilic (polar) heads
10
Q
What can readily cross the cell membrane and what cannot? And what do the ones that cannot use?
A
- Small polar molecules like water and small non polar molecules like oxygen are permeable to plasma membrane
- Small charged particles cross membrane via protein channels
- Charged ions or large charged molecules cross membrane via assistance of carrier proteins
11
Q
What is the nucleolus?
A
Where rRNA synthesis occurs, not surrounded by a membrane
12
Q
What is the nucleus and what is the nuclear envelope?
A
The genetic material of the cell is contained in the nucleus. The nuclear envelope, which separates the nucleus from the rest of the cell, consists of two membranes and is perforated by nuclear pores. The nuclear pores regulate the passage of large macromolecules into and out of the nucleus.
13
Q
What occurs in the ribosome and what is the functions of the ribosome in prokaryotes and eukaryotes
A
- Where protein production occurs
- Made of 2 rRNA sequences called ribosomal subunits
- Eukaryotes -> rRNA molecules made in nucleolus function either in cytoplasm as unbound ribosomes or on the outer membrane of the rough ER as bound ribosomes
- Prokaryotes -> lack of membrane bound organelles leads to both rRNA synthesis and ribosome function in cytoplasm
14
Q
How does a proteins final destination affect it’s production?
A
Proteins destined for the cytoplasm are synthesized by free ribosomes, while proteins destined for insertion into a membrane or secretion outside of the cell are synthesized by ribosomes bound to the rough endoplasmic reticulum.
15
Q
What is the endoplasmic reticulum (structure and function)?
A
- Network of membrane enclosed spaces involved in transport of materials throughout cells, especially materials destined to be secreted by cell
- Two types: Rough and smooth ER
- Rough ER-> studded with ribosomes, plays role in synthesis of proteins
- Smooth ER -> no ribosomes, involved with metabolism and production of lipids
16
Q
What is the function of the Golgi apparatus?
A
Receives vesicles from smooth ER and modifies them (like glycosylation), repackages them into vesicles and sends them to cell surface for exocytosis
17
Q
What is the structure and function of the mitochondria?
A
- Site of aerobic respiration
- Responsible for converting sugar, fats and other sources of energy into usable energy like ATP
- Has inner and outer phospholipid bilayer
- Inner membrane folded into cristae and has enzymes for ETC
- Within the inner membrane is the mitochondrial matrix
- Mitochondria have their own genome located in matrix (independent of cell genome and looks like bacterial circular chromosomes)
- Divide independently via binary fission
18
Q
Why do many poisons target the mitochondria?
A
The mitochondria are very important to the survival of a cell: many poisons target the mitochondria, and render it incapable of producing ATP. Without ATP, the cell cannot carry out its metabolic activities, and the cell dies
19
Q
How is mitochondrial DNA inherited?
A
Remember that a zygote receives all of its organelles from its mother; thus any mitochondrial DNA a person has is identical to that of his or her mother.
20
Q
What is the cytoplasm and what is its function?
A
- Includes the cytosol (cellular fluid contained within the cell membrane) and organelles
- Where most of the cells metabolic activity occurs
- Transport within the cytoplasm occurs by cyclosis (streaming movement within the cell)
21
Q
What are vacuoles and vesicles?
A
- Membrane bound sacs involved in the transport and storage of materials ingested, secreted, processed or digested by cell
- Vacuoles larger than vesicles and more likely to be found in plant than animal cells
22
Q
What are centrioles and what is their function?
A
- Made of microtubules
- Involved in spindle organization during cell division
- Not bound by membrane
- Animal cells usually have a pair in a region called centrosome
- Plant cells do not have centrioles
23
Q
What is the centrosome?
A
Centrosome organizes microtubules and regulates progression of the cell cycle
24
Q
What are lysosomes structure and function?
A
- Membrane bound vesicles with hydrolytic enzymes (intracellular digestion)
- Autolysis: Process when an injured or dying cell self-destructs by rupturing lysosome membrane and release hydrolytic enzymes
- The lysosome maintains a slightly acidic pH of 5 in its interior; this is the pH at which lysosomal activity is greatest
25
What is autolysis?
Autolysis: Process when an injured or dying cell self-destructs by rupturing lysosome membrane and release hydrolytic enzymes
26
What are peroxisomes?
Peroxisomes contain oxidative enzymes that catalyze reactions in which hydrogen peroxide is produced and degraded. Peroxisomes break down fats into small molecules; they are also used in the liver to detoxify potentially harmful compounds, such as alcohol
27
What is the structure and function of each type of cytoskeleton
- Supports the cell, maintains its shape and aids in cell motility
- Made of microtubules, microfilaments, and intermediate filaments
- Microtubules: hollow rods made of tubulin, provide support and framework for organelle movement; centrioles made of microtubules; cilia and flagella are special arrangements of microtubules that involved in cell motility and cytoplasmic movement
- Microfilaments:solid rods made of actin, important for cell movement and support, used in muscle contraction
- Intermediate filaments: Diverse group of filamentous proteins like keratin, structural backbone of cell, can withstand tension, anchor organelles and make cell structure more rigid
- Cilia and flagella are composed of long, stabilized microtubules arranged in a "9+2 structure": nine pairs of microtubules surrounding two central microtubules for added stability
28
What are the types of junctions in animal cells and give examples of where they can be found?
- In animal cells, there are three types of intercellular junctions: tight junctions, anchoring junctions, and gap junctions
- In tight junctions, the membranes of neighboring cells are attached, and the cells are bound together so tightly that no material can pass between cells or travel past the junction. Tight junctions, therefore, form a total barrier to transport and diffusion (intestine)
- Another type of cell junction found in animal cells is the anchoring junction. These junctions are found in cells subject to mechanical stress. For example, desmosomes are anchoring junctions that attach epithelial cells in the skin
- A third type of cell junction found in animal cells is the gap junction. These junctions provide a direct connection between the cytoplasm of one cell and the cytoplasm of a neighboring cell via channels. These channels are formed by proteins called connexins. In the heart, the flow of ions through gap junctions allows for rhythmic, coordinated contraction of the heart muscle
29
What is simple diffusion?
- Passive process (no energy needed)
| - Moving dissolved particles down their concentration gradient (from high to low concentration)
30
What is osmosis?
Simple diffusion of water from region of lower solute concentration to region of higher solute concentration
31
What is hypo, hyper and isotonic refer to?
- When cytoplasm of cell has lower solute concentration than the extracellular medium, the medium is said to be hypertonic to the cell and water will flow out of the cell into the surrounding medium, process also called plasmolysis and will cause cell to shrivel
- If extracellular environment is less concentrated then the cytoplasm of cell, the extracellular medium is said to be hypotonic and water will flow into the cell, causing it to swell and lyse
- If extracellular environment is same concentration of solutes as the cell cytoplasm, then cell is said to be isotonic to the environment and water will move back and forth in equal amounts across the cell membrane
32
What is facilitated diffusion?
- Passive transport (requires no energy)
- Net movement of dissolved particles down their concentration gradient through special channels or carrier proteins in the cell membranes
33
What is active transport?
- Net movement of dissolved particles against their concentration gradients with help of transport proteins
- Requires energy
- Carriers/transporters regulate the cells internal content of ions and large molecules
34
What are the types of carrier molecules?
- Symporters: move two or more ions or molecules in the same direction across the membrane
- Antiporters: Exchange one or more ions (or molecules) for another ion or molecule across the membrane
- Pumps: Energy dependent carriers that need ATP
35
What is endocytosis?
- Cell membrane invaginates and forms a vesicle containing extracellular medium (allows cell to bring large volumes of extracellular material into cell)
- Pinocytosis: Ingestion of fluids or small particles
- Phagocytosis: engulfing of large particles
- Receptor binding can trigger endocytosis
36
What is exocytosis?
Vesicle within the cell fuses with the cell membrane and releases large volume of contents to the outside
37
What is cell division consist of?
Process in which a cell doubles its organelles and cytoplasm, replicates DNA and then divides into 2
38
What is Interphase?
- Period of growth and chromosome replication
- Most of cell life (90%) spent in interphase
- After replication the chromosomes have 2 identical sister chromatids held together at central region called centromere
- During interphase the individual chromosomes are not visible and the DNA is uncoiled and called chromatin
39
What are the parts of interphase?
G1: Initiates interphase, active growth phase, cell increases size and makes proteins, variable length (time)
S: When DNA is synthesized
G2: Cell prepares to divide, grows and makes proteins
40
What is the M phase?
Last phase of cell cycle is M phase, where mitosis or meiosis occurs, resulting in either 2 identical cells (mitosis) or 4 non-identical cells (meiosis)
41
What occurs in mitosis?
- Division and distribution of cells DNA to 2 daughter cells and each cell receives complete copy of original genome
- Occurs in somatic cells
- Nuclear division (karyokinesis) is followed by cell division (cytokinesis)
- 4 phases: Prophase, metaphase, anaphase, telophase (I party more at the club)
42
What are the phases of mitosis and what occurs during each?
Prophase: cell prepares for nuclear division, chromatin is condensed into chromosomes, nuclear membrane dissolves, centriole pairs separate and move towards opposite poles of cell
Metaphase: Centrioles at poles of cell anchor themselves to the cell membrane through formation of spindle fibres, additional spindle fibres radiate from centriole and attach to each chromatid at the kinetochore (protein on centromere of chromosome) and aligns the chromosomes on the metaphase plate
Anaphase: Separation of sister chromatids of each chromosome, centromeres split and chromatids are pulled towards opposite poles by shortening spindle fibres
Telophase:Spindle apparatus disappears, nuclear membrane forms around each set of chromosomes, chromosomes uncoil
43
What occurs during cytokinesis in plant and animal cells?
Animal cells: Cleavage furrow forms and cell membrane indents along equator of cell pinching through cell
Plant cells: Cell plate forms between two nuclei, splits cell in half allowing cell to divide
44
What occurs during meiosis?
- Sex cells produced
| - Produces haploid cells (upon fertilization resulting cell is diploid)
45
What is ploidy?
Ploidy: Refers to how many chromosomes an organism has in a homologous set (chromosomes that share structure and gene locations but can have different alleles)
46
When does crossing over occur and what occurs during it?
Crossing Over: Homologous chromosomes intertwine (process called synapsis), structure is called tetrad (4 sister chromatids involved), interacting parts are called chiasmata, chromatids of homologous chromosomes break and exchange equivalent pieces of DNA
47
What occurs during each stage in the first meiotic division?
Prophase 1: chromatin condenses into chromosomes, spindle apparatus forms, nucleoli and nuclear membrane disappear, crossing over occurs (genetic exchange between chromatids to increase genetic diversity)
Metaphase 1: Homologous pairs align at equatorial plane and each pair attaches to a separate spindle fiber at the kinetochore
Anaphase 1: Homologous pairs separate and are pulled to opposite poles of the cell (process called disjunction),
Telophase 1: Nuclear membrane forms around new nucleus, 2 haploid cells form in which each chromosome has 2 sister chromatids (intermediate daughter cells)
48
What occurs during the second meiotic division?
Prophase 2: Nuclear envelope dissolves, nucleoli disappear, centrioles migrate to opposite poles and spindle apparatus begins to form
Metaphase 2: Chromosomes line up on the metaphase plate
Anaphase 2: Sister chromatids of each chromosome are separated and pulled apart (shortening spindle fibres), each separated sister chromatid is considered a chromosome itself
Telophase 2: Nuclear membrane forms, cytokinesis follows, 2 haploid daughter cells are formed per intermediate daughter cell, 4 haploid daughter cells produced
49
What is a nucleotide made of?
Nucleotide is made of deoxyribose (sugar) bonded to both a phosphate group and a nitrogenous base
50
What are the types of nitrogenous bases?
Purines: adenine and guanine
Pyrimidines: Cytosine and thymine and (uracil in RNA)
51
How many hydrogen bonds are formed between bases?
T forms 2 hydrogen bonds with A, and C forms 3 hydrogen bonds with G
52
What does DNA helicase do?
DNA helicase can break hydrogen bonds between bases and unwind DNA, opening the DNA and creating a replication fork
53
What does topoisomerase do?
Topoisomerase removes strain of replication fork by cutting, twisting and then rejoining the strands of DNA
54
What type of replication is DNA replication?
Semiconservative replication where the daughter strands of DNA formed from the parent strands are identical with one parent helix and one newly synthesized strand
55
Which way does DNA polymerase read and synthesize the DNA strands?
- DNA polymerase reads the parent strand in a 3’ to 5’ direction, creating a new daughter strand in the 5’ to 3’ direction
- DNA polymerase adds nucleotides to the 3’ ends of DNA strands
56
What is the difference between the leading strand and the lagging strand?
Leading strand has its 3’ end facing towards the replication fork allowing DNA polymerase and the replication fork to travel in same direction
Lagging strand has its 3’ end facing away from the replication fork and go in opposite directions, results in discontinuous synthesis of short fragments of DNA called okazaki fragments
57
What does DNA ligase do?
DNA ligases joins the fragments of the lagging strand together
58
What processes occur in the 5’ to 3’ direction?
DNA synthesis, DNA repair, RNA transcription and RNA translation occurs in the 5’ to 3’ direction
59
In what direction is the mRNA translated and the protein synthesized?
The ribosome translate the mRNA in the 5’ to 3’ direction and the protein is synthesized from the amino terminus (N terminus) to the carboxyl terminus (C terminus)
60
What are the differences between RNA and DNA?
The sugar is ribose instead of deoxyribose
Uracil is used instead of thymine
Most RNA is single stranded
61
What are the 3 major types of RNA?
MRNA, tRNA and rRNA
62
What is mRNA do?
mRNA: carries the complement of a DNA sequence, transport this information from nucleus to ribosome for protein synthesis, mRNA in eukaryotes is monocistronic (1 mRNA codes for one polypeptide)
63
What does tRNA do?
- Small RNA molecule found in the cytoplasm
- Assists in the translation of mRNAs into a sequence of amino acids by bringing the amino acids coded for in the mRNA to the ribosomes during protein synthesis
- tRNA recognizes both the mRNA codon and its corresponding amino acid
- there is at least 1 tRNA for each amino acid (approx 40 types)
64
What is the structure of tRNA?
- One end of tRNA has anticodon (3 nt sequence complementary to the mRNA codon) and the other end has an attachment site for corresponding amino acid
- Every amino acid has its own aminoacyl-tRNA synthetase that binds to both the amino acid and its corresponding tRNA, catalyzing their attachment to form a complex
- When a tRNA is complexed with its amino acid, it's called a charged tRNA
65
What is the function of rRNA and where is it made in prokaryotes and eukaryotes?
- rRNA is made in nucleolus in eukaryotes
- rRNA is made in cytoplasm in prokaryotes
- rRNA is most abundant type of RNA in cell
- Important part of ribosomal machinery and used during protein assembly in cytoplasm
66
What is the common promoter for transcription in prokaryotes and eukaryotes?
Eukaryotes Common Promoter: TATA box (30 bp upstream)
| Prokaryotes Common Promoter: Pribnow box (10 bp upstream-> TTGACA)
67
What occurs during transcription?
- RNA polymerase binds to DNA template strand at promoter region
- For RNA polymerase to bind to promoter, transcription factors must assist
- Once RNA polymerase is bound to template strand, it recruits and adds complementary RNA nucleotides (reads in 3’ to 5’ direction and makes RNA in 5’ to 3’ direction like DNA polymerase)
68
What is hnRNA?
RNA that is not yet processed is called hetero-nuclear RNA (hnRNA) or pre-mRNA
69
What occurs during post transcription processing?
- Introns are spliced out/removed by the spliceosome
- Exons are the nucleotides necessary to make the protein and kept during post-transcriptional processing
- RNA also has to gain 5’ guanine cap and 3’ poly-A-tail (prevent degradation in cytosol)
- Once down its mRNA and can leave nucleus
70
What are codons and what direction are they written in?
- Codons are 3 nucleotide sequences on the mRNA that correspond to a specific amino acid
- Codons are written in 5’ to 3’ direction
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What are the stop codons?
Stop Codons: UAA, UGA, UAG (you are annoying, you go away, you are gone)
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Why is the genetic code considered redundant and degenerate?
Multiple codons code for the same amino acid (redundant and degenerate-> can’t convert back to mRNA)
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What does wobble position refer to?
Wobble position-> aminoacyl-tRNA complex’s ability to bind to mRNA despite having non-complementary base pairs for 3rd nucleotide
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What is translation and where does it occur?
- mRNA codons are translated into a sequence of amino acids
| - Translation occurs in the cytoplasm and involves ribosomes (rRNA), mRNA, tRNA, amino acids, enzymes and proteins
75
What are the stages of translation?
Initiation: Small ribosomal subunit binds to the mRNA near its 5’ end, scans until start codon (AUG), aminoacyl-tRNA complex is bound with mRNA and small ribosomal subunit -> the large ribosomal subunit binds forming the initiation complex
Elongation: Ribosome moves in the 5’ to 3’ direction along the mRNA synthesizing the protein from its N to C terminus
Translocation: RIbosome advances 3 nucleotides along the mRNA and the charged tRNA is shifted from the A site to the P site and uncharged tRNA is transferred from P site to E site to be expelled; after translocation the A site is empty
Termination: When stop codon is encountered
76
What are the binding sites on the ribosome?
- A site holds in incoming aminoacyl-tRNA complex which will be the next amino acid added to the growing chain
- P site holds the tRNA that carries the growing polypeptide chain, peptide bond forms when polypeptide is passed from the tRNA in the P site to the tRNA in the A site
- E site is where the uncharged tRNA pauses before its kicked out from ribosome to be recharged
77
What are some examples of post translational modifications?
- Can be cleavage or addition
| - Common addition processes: phosphorylation, glycosylation, carboxylation, or prenylation (adding lipids)
78
Where does transcription occur in prokaryotes and eukaryotes?
Transcription occurs in nucleus for eukaryotes but in the cytoplasm for prokaryotes
79
What are the differences in transcription for prokaryotes then eukaryotes?
- After transcription in prokaryotes there is no post transcriptional modifications (have polycistronic mRNA transcripts compared to monocistronic ones of eukaryotes)
- Transcription and translation can occur at same time for prokaryotes because lack of membrane bound organelles
80
What are the levels of protein structures?
Primary: sequence of amino acids (listed N to C terminus) linked via peptide bonds
Secondary: local 3-D structure of neighbouring amino acids, usually a helix or beta sheets
Tertiary: Folding of polypeptide forming the 3D structure of the entire protein itself, usually assisted by chaperones, relies on hydrophobic/hydrophilic interactions of side groups and disulfide bonds
Quaternary: combining polypeptides to form a complete protein complex, not always present in proteins
81
What are proteins that are not enzymatic?
```
Structural proteins (cytoskeleton and motor protein)
Binding proteins (transport, attach, or sequester molecules)
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82
What is a catalyst?
Catalyst: Affects the rate of a chemical reaction while remaining unchanged or being regenerated as a product, usually increase reaction rate through reduction of activation energy
83
What are conjugated proteins?
Conjugated proteins covalently bond to other groups (lipids, sugars, cations etc) that often serve as coenzymes or cofactors
84
What is a substrate?
The molecule that the enzyme acts on
85
What is the active site?
The area on enzyme where the substrate binds
86
TRUE OR FALSE: Enzymes alter the equilibrium constant?
FALSE: Enzymes don't alter the equilibrium constant, they are not consumed in the reaction, they are pH and temperature sensitive (have optimal values)
87
What is the Lock and Key Theory?
Lock and Key theory: enzyme active site and substrate fit like lock and key
88
What is the induced fit theory?
Induced fit theory: More widely accepted, active site has flexibility for shape, when right substrate comes the conformation of active site changes to fit substrate
89
What happens to enzyme activity when temperature increases?
As temperature increases, the rate of enzyme action increases until optimal temperature (around 37 degrees) anything after bad
90
What is the optimal pH for human enzymes?
Many human enzymes function best at pH around 7.2 (some in stomach prefer more acidic and some in small intestine prefer basic)
91
What occurs to the reaction rate and enzymes when you continually increase substrate concentration?
Increasing substrate concentration will increase reaction rate until all active sites are occupied (saturated) and Vmax is reached
92
What is Vmax?
Vmax is the reaction rate as substrate concentration goes to infinity (more enzyme can be added to change it)
93
What is Km?
- Km (michaelis constant) is the substrate concentration needed to fill half of the enzymes active sites (½ of Vmax)
- The higher the Km the lower the enzyme's affinity for that substrate
- The lower the Km the higher the enzyme's affinity for that substrate
94
What is competitive inhibition?
Competitive Inhibition: Molecules similar to the substrate bind to the active site and compete with substrate for binding sites on enzyme, interfere with enzyme activity
95
What is non competitive inhibition?
- Noncompetitive Inhibition: A substance that binds to an enzyme at a site other than the active site (at an allosteric site), changing structure of enzyme and results in nonfunctional active site
- Noncompetitive inhibition is considered to be a type of allosteric inhibition
96
What do ligases do?
Ligases: catalyze addition or synthesis reactions usually between large similar molecules, usually need ATP
97
What do isomerases do?
Isomerases: catalyze the rearrangement of bonds within a molecule
98
What do lyases do?
Lyases: Catalyze the cleavage of a single molecule into 2 products, synthases are ones that reverse the synthesis of two small molecules, dont need water
99
What do hydrolases do?
Hydrolases: catalyze the breaking of compound into 2 molecules using addition of water, examples are phosphatases, peptidases, nucleases, lipases
100
What do oxidoreductases do?
Oxidoreductases catalyze oxidation reduction reactions, transfer of electrons, often have a cofactor (electron carrier like NAD+), e.g. dehydrogenase or reductase
101
What do transferases do?
Transferases: catalyze the movement of functional group from 1 molecule to another, e.g. kinases
102
What is metabolism?
Metabolism: Sum of all chemical reactions that occur in the body
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What are the two types of reactions?
Catabolic Reactions: Break down chemicals and release energy
| Anabolic Reactions: Synthesize chemicals and require energy
104
What are examples of anabolic and catabolic processes?
DNA replication and protein synthesis: anabolic
| Cellular respiration is catabolic (convert chemical energy in molecular bonds to usable energy like ATP)
105
What is external respiration and what is internal respiration?
External: Inhaling and exhaling air into and out of lungs, gas exchange between alveoli and blood
Internal: gas exchange between cells and extracellular fluid
106
What is the general equation of cellular respiration?
C6H12O6 + O2 -> H2O +CO2
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Where does glycolysis occur?
In the cytoplasm in both prokaryotic and eukaryotic cells
108
What occurs in glycolysis?
Glycolysis: breakdown of glucose into 2 molecules of pyruvate, production of ATP, and reduction of NAD+ into NADH,glucose is oxidized and NAD+ is reduced
109
What are the stages of glycolysis?
- Energy Investment: step 1-3, 2 ATPS used to add 2 phosphates to glucose (using kinases)
- Cleavage: step 4, Fructose 1,6 bisphosphate goes to PGAL and DHAP and DHAP goes to second PGAL
- Energy Payout: steps 5-9, production of ATP, PGAL converted to pyruvate, reduction of NAD+ to NADH, production of 2 ATP (per PGAL)
110
How many ATP are made and used in glycolysis?
Glycolysis: 2 ATP used, 4 ATP generated, net 2 ATP per glucose
111
What is substrate level phosphorylation and what is oxidative phosphorylation?
- Substrate level phosphorylation: ATP synthesis is directly couple with the oxidation of glucose without need of intermediate molecule like NADH
- Oxidative Phosphorylation: needs intermediate electron carrier like NADH or FADH2
112
What is the net reaction of glycolysis?
Glucose + 2 ADP + 2 Pi + 2 NAD+ -> 2 pyruvate + 2 ATP + 2 NADH + 2 H+ + 2 H2O
113
How much ATP does anaerobic respiration yield?
Yields 2 ATP per glucose only (from glycolysis)
114
What is alcohol fermentation?
Alcohol fermentation: occurs in yeast and bacteria, pyruvate produced in glycolysis is converted to ethanol so NAD+ is regenerated and glycolysis can continue
115
What is lactic acid fermentation?
Lactic Acid Fermentation: Occurs in some fungi and bacteria and human muscle cells during exercise, NAD+ is regenerated once again
116
How much ATP does aerobic respiration yield?
36-38 ATP
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What are the stages of aerobic respiration and where do they occur in the different cell types?
Stages: Pyruvate decarboxylation, citric acid cycle, and electron transport chain (stages occur in mitochondria for eukaryotes and cytoplasm for prokaryotes)
118
Where does the citric acid cycle and electron transport chain occur in prokaryotes?
Prokaryotes: CAC occurs in cytosol and ETC on bacterial membrane itself
119
What generally occurs during aerobic respiration?
Pyruvate produced from glycolysis transported into mitochondrial matrix to undergo Pyruvate decarboxylation and produce acetyl-CoA which undergoes reactions in CAC to produce electron carriers (NADH and FADH2) while regenerating oxaloacetate, electron carriers power ETC on inner mitochondrial membrane which moves H+ against concentration gradient to intermembrane space and energy used by ATP synthase on inner membrane to produce ATP
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What is pyruvate decarboxylation?
Pyruvate transported from cytoplasm to mitochondria matrix where it loses a CO2 and acetyl group remaining is transferred to coenzyme A to form acetyl-coa and NAD+ reduced to NADH
121
What occurs during the citric acid cycle and how many ATPs are produced? And what else is produced?
- Acetyl-coa (2C) and oxaloacetate (4C) combine, Two CO2 released, oxaloacetate (4C) is regenerated for next use of cycle
- One ATP produced per cycle via substrate level phosphorylation via GTP intermediate
- One cycle produces 3 NADH and 1 FADH2
- Above is for one acetyl coa since we have 2 everything doubled (for 1 glucose)
122
What is the net reaction of the citric acid cycle?
Per glucose molecule:
2 acetyl-CoA + 6 NAD+ + 2 FAD + 2 GDP +2 pi + 4 H2O -> 4 CO2 + 6 NADH + 2 FADH2 + 2 GTP + 4 H+ + 2 CoA
123
What occurs on the electron transport chain and where is it located?
- Located on inside of inner mitochondrial membrane
- Electrons transferred from NADH and FADH2 to oxygen via carrier molecules on inner mitochondrial membrane, as electrons transfer free energy released which is used to form ATP,
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What are cytochromes?
Electron carriers that resemble hemoglobin in the structure of their active site, central iron atom capable of reversible redox reaction
125
How is ATP generated via the proton pump?
- When electrons are passed during ETC-> H+ ions pumped out of matrix into intermembrane space, intermembrane space accumulates H+ becomes acidic and positively charged -> electrochemical gradient creates proton motive force, drives H+ back across inner membrane into matrix, to pass through membrane the H+ flow through channels provided by atp synthases,as they pass through enough energy released to allow phosphorylation of ADP to ATP
- Coupling of the oxidation of NADH and FADH2 with phosphorylation of ADP is called oxidative phosphorylation
126
How much ATP is produced in respiration from substrate and oxidative phosphorylation?
- 4 ATP produced by substrate phosphorylation (2 from glycolysis and 2 from CAC)
- Oxidative phosphorylation: Eukaryotes: 32 ATP and Prokaryotes: 34 ATP
127
What happens when glucose is running low in the body?
Glucose is running low-> body uses other energy sources: prefers -> other carbohydrates, then fats, then proteins (these substances are converted to either glucose or glucose intermediates which then can undergo glycolytic pathway and CAC)
128
How does the body use CHO, proteins and fats for metabolism?
- Carbohydrates: Disaccharides hydrolyzed into monosaccharides which can be converted to glucose or glycolytic intermediates, also can use glycogen in liver as intermediate
- Fats: Fats using lipases are converted to fatty acids and glycerol, glycerol can be converted into PGAL, fatty acid has to be activated in cytoplasm (needs 2 ATP and then in mitochondria can be converted to Acetyl-coa which can enter CAC, fats yield greatest number of ATP per gram (efficient energy storage molecules)
- Proteins: amino acids undergo transamination reaction (lose amino group) to form alpha-keto acid, carbon atoms from amino acids converted to acetyl-coa, pyruvate or intermediate of CAC, oxidative deamination removes ammonia from amino acid
129
How do photosynthetic bacteria work?
Have membranes that function similar to chloroplasts
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What occurs during photosynthesis?
- Convert CO2 and water into glucose and oxygen
- Glucose can be stored (starch) or used as an energy source
- Plants: photosynthesis occurs in chloroplasts
- Reduction of CO2 and release of oxygen from water
131
What is the net reaction of photosynthesis?
6 CO2 + 12 H2O + light energy -> C6H12O6 +6 O2 +6 H2O
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What are the light and dark reactions in photosynthesis (brief)?
- Has light reactions which need sunlight and dark reactions coupled with the light ones and dont need sunlight
- Light reactions: (photolysis reactions)Split H2O to produce ATP and NADPH
- Dark reactions: (reduction synthesis) form sugar from CO2 and energy from light reactions
133
What occurs in the light reactions (specific)?
- Absorption of photon of light by chlorophyll molecule, p700 in photosystem1 excites electron to higher energy level, electron can flow in 1 of 2 pathways: cyclic electron flow or noncyclic electron flow
- Cyclic electron flow: electron moves along chain of electron carriers, redox reactions ultimately return the electrons to p700, generates ATP via cyclic photophosphorylation, no oxygen nor NADPH generated
- Noncyclic Electron Flow: electrons transferred to NADP+ to form NADPH, leaves electron holes in p700, light strikes p680 in photosystem 2, electrons travel down same electron carrier chain used in cyclic electron flow until they reach p700 and fill electron holes, cascade products ATP by noncyclic photophosphorylation, p680 has electron holes now but is a strong enough oxidizing agent to oxidize water and fill its holes (water split), oxygen atoms combine to form O2, results: production of NADPH and ATP and photolysis (breakdown) of water
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What occurs during the dark reactions (specific)?
- Use ATP and NADPH produced by light reactions to reduce CO2 into carbohydrates
- Reactions occur during the day even though they don't need light (light reactions replenishing amount of ATP and NADPH)
- CO2 is source of carbon for carbohydrate production in the calvin cycle
- To produce a 3 carbon sugar from CO2, the cycle must take place 3 times
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What is the Calvin cycle?
- Add CO2 to ribulose bisphosphate (5 carbon sugar) (RBP), makes unstable 6 carbon molecule which splits to form 2 PGA (phosphoglyceric acid), PGA is phosphorylated and reduced (by ATP and NADPH) to form PGAL, most of PGAL is recycled to make RBP, two molecules of PGAL can be converted to glucose which can be oxidized to provide usable energy
- In 6 turns of calvin cycle, 12 PGAL are formed from 6 CO2 and 6 RBP; 12 PGAL form 6 RBP and 1 glucose
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What is genetics?
Genetics: Study of how traits are inherited from one generation to the next
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What is a gene, what are they made of, and where are they located?
- Gene: Basic unit of heredity
- Genes composed of DNA and located on chromosomes
- Alternative forms of genes are alleles
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What are Mendels 4 principles of inheritance?
- Genes exist in alternative forms (alleles); a gene controls a specific trait in an organism
- An organism has 2 alleles for each inherited trait, one inherited from each parent
- The 2 alleles segregate during meiosis, resulting in gametes that carry only one allele for any given inherited trait
- If 2 alleles in an individual are different, only one will be fully expressed and the other will be silent (Mendel’s Law of Dominance)
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How do you perform a test cross?
Testcross: Cross the suspected (which is either heterozygous or homozygous dominant) with homozygous recessive
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What is Mendels Law of Independent Assortment?
Mendel’s Law of Independent Assortment: Inheritance of one trait is completely independent of any other
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What does the proximity of genes affect?
The closer genes are on chromosomes, the more likely they are to be inherited together
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Why are flies used for genetics studies?
Flies used for genetics-> large amounts of offspring and short life span
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What is incomplete dominance?
Phenotype of the heterozygote is an intermediate of the phenotypes of the homozygotes
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What is codominance?
- Occurs when multiple alleles exist for a given gene and more than one of them is dominant
- Example is blood groups
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Where are most sex-linked genes located?
Most sex-linked genes are on the X chromosome because its larger than Y
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What does sex linkage refer to?
Recessive genes on X chromosome are more likely shown in males
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How does environment affect expression of a gene?
- Environment can affect the expression of a gene
| - Interaction between the environment and genotype produces the phenotype
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What is cytoplasmic inheritance?
- Cytoplasmic genes can interact with nuclear genes and are important in determining the characteristics of their organelles
- E.g. drug resistance encoded in plasmids
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What is nondisjunction?
Nondisjunction: Failure of homologous chromosomes to separate properly during meiosis 1 or the failure of sister chromatids to separate properly during meiosis 2; can result in trisomy (3 copies of chromosome) or monosomy (1 copy)
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What is the only viable monosomy?
Only viable monosomy is Turner’s syndrome which is monosomy of sex chromosomes (XO)
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What are the types of chromosomal abnormalities?
Chromosomal abnormalities can be either constitutional (the abnormality is found in all cells of the body) or somatic/acquired (the abnormality is found only in certain cells or tissues)
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What are the categories of chromosomal abnormalities?
- Numerical – The gain or loss of complete chromosomes
- Structural – The formation of abnormal chromosomes through the misrepair of chromosome breaks or a malfunction during recombination
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What is an aneuploidy?
Aneuploidy – One or more chromosomes are missing or are present in more than the normal number. Aneuploidy usually results from nondisjunction, which is the failure of paired chromosomes to separate in anaphase (usually during meiosis I).
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What is euploidy?
Euploidy – An extra, complete set of chromosomes is present or missing
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What is mosaicism?
Mosaicism – Two or more genetically different cell lines within a single individual derived from a single zygote
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What is chimerism?
Chimerism – Two or more genetically different cell lines within a single individual derived from different zygotes
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What is translocation?
Translocation – chromosomal material is exchanged between non-homologous chromosomes
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What are the types of chromosomal translocation?
- Reciprocal – there is no loss of genetic information although gene arrangement is altered (considered a balanced translocation)
- Robertsonian – the short arm of two chromosomes breaks off and the long arms are fused together; this can result in a balanced translocation or an unbalanced translocation in which genetic material is gained or lost
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What does the mitochondria genome consist of?
The mitochondrial genome consists of double-stranded, and a very short portion of triple-stranded, circular DNA. It contains 37 genes, 24 of which code for a type of RNA and 13 of which code for polypeptides that are used in the respiratory complexes that produce ATP.
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How is mitochondria DNA inherited?
Mitochondrial DNA (mtDNA) is maternally inherited. Mitochondria from sperm are destroyed by the egg after fertilization, leaving only maternal mtDNA originally found in the unfertilized egg.
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What are proto-oncogenes and oncogenes?
Non-mutant versions of genes that control cell proliferation are known as proto-oncogenes. A mutation that results in a gain of function can alter the gene to become an oncogene, which is excessively active and causes cellular hyperproliferation – the basis of cancer. Only one mutant allele is necessary to affect the function of the cell
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What is a tumor suppressor gene?
Tumor suppressor genes inhibit pathways that lead to cancer. A mutation in a tumor suppressor gene causes a loss of function of the tumor suppressor gene product, which can result in cancer. Both copies of an allele must experience loss of function in order for the function of the cell to be affected.
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What is a gene mutation?
Gene mutation: nitrogenous bases are added, deleted or substituted
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What is a point mutation and what are the types?
Point mutation: a nucleic acid is replaced by another nucleic acid can lead to:
- Silent mutation: same amino acid is coded
- Missense Mutation: codon codes for a different amino acid
- Nonsense mutation: New codon is a stop codon
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What is a frame shift mutation?
Frameshift mutation: Nucleic acids are deleted or inserted (usually lethal), length of genome changes
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What is a base substitution and what is transversion?
Base substitution: transition when its purine to purine or transversion when its purine to pyrimidine
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What is direct repair?
Direct Repair reverses DNA damage without cutting the deoxyribose phosphate backbone (e.g. removing a methyl group in order to restore the original base).
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What is base excision repair?
Base Excision Repair (BER) is used when incorrect bases are present in DNA (e.g. U is incorporated into DNA). The damaged base is recognized by a glycosylase and is hydrolytically removed from the deoxyribose phosphate backbone. This leaves an apurinic or apyrimidic site where the purine or pyrimidine was removed. The correct base is then inserted and the break is sealed by DNA ligase.
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What is mismatch repair?
Mismatch Repairs use a method similar to BER to remedy incorrect pairings of the normal bases (e.g. A paired with C or G will be repaired so that A pairs with T and C pairs with G).
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What is nucleotide excision repair?
Nucleotide Excision Repair (NER) removes thymine dimers and bulky adducts. The area of DNA surrounding and including the damaged portion is unwound and an endonuclease makes cuts on both the 5’ and 3’ sides of the damage. The bases are removed by an exonuclease and DNA is resynthesized, using the sister strand as a template to fill the gap. DNA ligase seals the new section into the backbone
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What are characteristics of the bacterial genome?
- Has single circular chromosome located in nucleoid region of cell
- Has plasmids
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What are episomes?
Episomes are plasmids that are capable of integration into the bacterial genome
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How does replication in bacteria occur?
Bidirectional in the 5’ to 3’ direction
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How does bacteria reproduce?
Reproduce through binary fission (asexual)
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What are the mechanisms for increasing genetic variance in bacteria?
3 mechanisms for increasing genetic variance: transformation, conjugation and transduction
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What is transformation?
Transformation: Process which a foreign chromosome fragment (plasmid) is incorporated into the bacterial chromosome via recombination, creating new inheritable genetic combinations
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What is conjugation?
Conjugation: sexual mating in bacteria, transfer of genetic material between two bacteria that are temporarily joined; only bacteria containing plasmids called sex factors are capable of conjugating
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What is transduction?
Transduction: fragments of bacterial chromosome have been packaged into the viral progeny produced during a viral infection, closer 2 genes are to one another on a chromosome, the more likely they will be to transduce
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How do Hfr cells combine into the cell?
HFr cells (high frequency of recombination): Conjugation bridge breaks before entire chromosome is transferred, bacterial genes that enter recipient can easily recombine with genes already present to form new genetic combinations
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What does an operon do and what is it made of?
Regulation of transcription is based on the accessibility of RNA polymerase to the genes being transcribed, directed by an operon (consists of structural genes, an operator region, and a promoter region)
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What is an operator?
Operator is the sequence of non transcribable DNA that is the repressor binding site
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What is a promoter?
Promoter is the noncoding sequence of DNA that serves as the initial binding site for RNA polymerase
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How does a regulator gene work?
Regulator gene-> codes for the synthesis of a repressor molecule that binds to the operator and blocks RNA polymerase from transcribing the structural genes
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What are inducible and repressible systems?
- Inducible Systems are those that require the presence of a substance (INDUCER), for transcription to occur
- Repressible systems are in a constant state of transcription unless a corepressor is present to inhibit transcription
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How does an inducible system work?
- Repressor binds to operator; prevents RNA polymerase from transcribing structural genes
- For transcription to occur, an inducer needs to bind to the repressor to prevent it from forming barrier
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How do repressible systems work?
Repressor is inactive until it combines with the corepressor, then this complex can bind to the operator and prevent transcription
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What are key features of an autosomal recessive pedigree?
- Can skip generations, affects equal numbers of males and females
- Noted when two unaffected parents have affected offspring
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What are key features of an autosomal dominant pedigree?
No skipping, affects equal numbers of males and females
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What are the key features of an x-linked recessive pedigree
- Affected mothers pass it to their sons
- Can skip generations
- More males affected than females
- Two unaffected individuals can produce affected offspring
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What is evolution?
Evolution: Change in genetic makeup of a population with time
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What is Lamarckian evolution?
Lamarckian evolution: any useful characteristic acquired was passed to next (giraffe and long neck stretched)
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What is Darwins theory of natural selection?
Darwin Theory (Natural Selection): Pressures in environment select for the organism most fit to survive and reproduce
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What is fitness?
Fitness: Ability to survive and reproduce
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What is speciation?
Speciation: Evolution of a new species
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What are factors that can lead to speciation?
Factors that can lead to speciation: genetic variation, changes in environment, migration, adaptation, natural selection, genetic drift, isolation
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What is convergent evolution?
When two species from different ancestors develop similar traits
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What is parallel evolution?
Similar to convergent evolution but occurs when a more recent ancestor is identified
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What is divergent evolution?
Species with a shared ancestor develop different traits due to dissimilarities between their environments
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What is adaptive radiation?
- Emergence of a number of lineages from a single ancestral species
- Difference between them due to their adaptations to their niche
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What is a gene pool?
Gene pool of a population is the sum total of all the alleles for any given trait in the population
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What are the conditions that have to be met by the Hardy-Weinberg Principle?
Population is very large, no mutations affect the gene pool, mating between individuals in the population is random, no net migration of individuals in or out of population, the genes in population are all equally successful at reproducing
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What is the Hardy-Weinberg Equation?
p^2 +2pq + q^2 =1
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What are agents of micro evolutionary change?
Agents of microevolutionary change: natural selection, mutation, genetic drift, gene flow and assortive mating (sexual selection)
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What is genetic drift and the 2 types?
-Genetic drift is change in the composition of the gene pool due to chance
—Large die off events -> bottleneck
—Founder effect-> making of small or new population
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Where are fossils usually found?
Fossils generally found in sedimentary rock
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What is amber?
Amber (fossil resin of trees)
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What is petrification?
Petrification is when minerals replace the cells of an organism
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What are homologous structures?
Same origins and anatomical features but can have different functions
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What are analogous structures?
Similar functions but may have different evolutionary origins and different patterns of development
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What are vestigial structures?
Vestigial structures: have no known current function but had some in ancestors
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What was the evidence of organic synthesis?
Evidence of Organic synthesis: stanley miller put hydrogen methane ammonia and water resulted in formation of organic compounds like urea, acetic acid and lactic acid
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What are autotrophs?
Autotrophs are able to produce organic compounds from substances in their surroundings
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What are the general categories of living organisms?
General Categories of Living Organisms: autotrophic anaerobes, autotrophic aerobes, heterotrophic anaerobes, heterotrophic aerobes
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What is the order of taxa?
Taxa: Domain, Kingdom, Phylum, Class, Order, Family, genus and species
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What is binomial nomenclature?
Genus, species
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What are reflexes?
Reflexes are the automatic responses to simple stimuli
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What does a simple reflex involve?
A simple reflex is controlled at the spinal cord, connecting a two neuron pathways from receptor (afferent neuron) to the motor (efferent neuron)
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What do efferent nerves innervate?
Efferent nerve innervates the effector (muscle or gland)
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What does the startle response involve?
The startle response involves the integration of many neurons in a system termed the reticular activating system which is responsible for sleep-wake transitions and behavioral motivation
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What are circadian rhythms?
Circadian Rhythms: daily cycles of behavior, animals using this lose some of it if isolated from natural phases of light and dark
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What is habituation?
Habituation: Simple learning pattern, involves the suppression of the normal start response to stimuli, repeated stimulation results in decreased responsiveness to stimulus
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What is classical/Pavlovian conditioning?
Classical/Pavlovian conditioning: Involves the association of a normally autonomic response with an environmental stimulus, response learned through conditioning can be called a conditioned reflex, normal innate stimulus for reflex is chosen by experimenter
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What is an innate reflex?
An established (innate) reflex consists of an unconditioned stimulus (food) and the response that is naturally elicited, the unconditioned response (salivation)
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What is a neutral stimulus?
A neutral stimulus is a stimulus that will not by itself elicit the response, can be associated with unconditioned stimulus and become a conditioned stimulus and produces a conditioned reflex
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What is conditioning?
Conditioning: establishment of a new reflex (association of stimulus with response) by addition of a new, previously neutral stimulus to the set of stimuli that was already capable of triggering the response
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What is pseudoconditioning?
Pseudoconditioning: when the neutral stimulus actually had somewhat of a response before starting conditioning experiments
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What is operant/instrumental conditioning?
Operant or Instrumental conditioning: Involves conditioning responses to stimuli with use of reward or reinforcement
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What is positive reinforcement?
Positive reinforcement: Reward (stimulate brain's pleasure center) to make animal much more likely to repeat the desired behavioral response
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What is negative reinforcement?
Negative reinforcement: Links a certain behavior to the removal of something unpleasant, animal develops positive connection between the action and the removal of something unpleasant-> more likely to repeat behavioral response
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What is punishment?
Punishment: Conditioning an organism so that it will stop exhibiting a given behavior pattern, less likely to repeat behavioral response with punishment because develops negative connection between stimulus and response
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What is habit family hierarchy?
Habit family hierarchy: Reward strengthens a specific behavioral response and raises its order in the hierarchy and punishment lowers it
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What is extinction (psych)?
Extinction: Gradual elimination of conditioned responses in the absence of reinforcement (unlearning the response pattern)
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What is spontaneous recovery?
The recovery of the conditioned response after extinction is called spontaneous recovery
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What is stimulus generalization?
Stimulus generalization: Ability of a conditioned organism to respond to stimuli that are similar but not identical, to the original conditioned stimulus
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What is stimulus discrimination?
Stimulus Discrimintion: Ability of the learning organism to respond to differentially to slightly different stim
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What is stimulus generalization gradient?
Stimulus generalization gradient: Stimuli further and further away from the original conditioned stimulus elicit responses with decreasing magnitude
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What is imprinting?
Imprinting: Process in which environmental patterns or objects presented to a developing organism during a brief critical period in early life become accepted permanently as an element of its behavioral environment (stamped in and included in an animals behavioral response)
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What is critical period?
Critical Period: Specific time periods during an animals early development when it is physiologically able to develop specific behavioral patterns
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What are the types of behavioral displays?
- Reproductive displays: Specific behaviors function as signals in preparations for mating
- Agonistic displays: Specific behaviors that function to reduce physical harm to the animal (aggressive behaviors to intimidate rivals/predators)
- Dancing procedures -> can convey information concerning quality and location of food sources (used as communication)
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What is the social hierarchy?
The social hierarchy is referred to as the pecking order, where if something is disputed a dominant member of the species will prevail over a subordinate one, pecking order minimizes violent intraspecific aggresions by defining stable relationships among members of the group
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What is the function of territoriality?
Territoriality serves the adaptive function of distributing members of the species, so environmental resources are not depleted in a small region, reducing intraspecific competition
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What are pheromones?
- Animals secrete substances called pheromones which influence the behavior of other members of the same species
- Released pheromones can trigger a reversible behvaioral change in the recipient ( like sex attractant or can be alarm or toxic defensive substance)
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What are primer pheromones?
Primer pheromones produce long-term behavioral and physiological alterations in the recipient, can regulate role determination and reproductive capacities
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What is ecology?
Ecology is the study of the interactions between organisms and their environment
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What is abiotic and biotic factors?
Abiotic: Climate, temperature, availability of light and water, local topology
Biotic: All living things that directly or indirectly influence the life of the organism
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What is a species?
A species is any group of similar organisms that are capable of producing fertile offspring
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What is a population?
Population: group of organisms of the same species living in the same habitat
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What is a biotic community and what is an ecosystem?
Biotic community is just the population while ecosystem includes the community and the environment
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What is ecological succession? And what is primary and secondary succession?
- Ecological succession is the orderly process by which the structure of an ecological community evolves over time
- Primary succession occurs in area uninfluenced by a pre-existing community
- Secondary succession occurs in areas where a pre-existing community has been disrupted
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What are pioneer organisms?
Pioneer Organisms: species able to colonize a barren area, allowing other organisms to follow
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What is a climax community?
Climax community is the living (biotic) part of an ecosystem in which populations exist in balance with each other and with the environment
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What is the criteria for a self-sustaining and stable ecosystem?
- Abiotic factors and biotic community are relatively stable
- There is a constant energy source and a biotic community incorporating this energy into organic compounds
- Materials are cycled between the abiotic factors and biotic community
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What are biomes?
Ecosystems within a specific geographic region form biomes
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What are the types of terrestrial biomes?
Desert, grassland, rainforest, temperate deciduous forest, temperate coniferous forest, taiga, tundra, and polar
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What are characteristics of the desert biome?
Desert biome: minimal rain, inhabited by small plants and animals, plants conserve water, animals live in burrows, few birds and mammals except ones adapted
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What are characteristics of the grassland biome?
Grassland Biome: low rainfall, no shelter for herbivore mammals from carnivorous predators, land animals present usually have long legs and hoofs
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What are characteristics of the rainforest biome?
Rainforest biome: torrential rains, temperature is moderate, dense vegetation that doesn't shed its leaves, have vines and epiphytes (plants growing on other plants)
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What are characteristics of the temperate deciduous forest biome?
Temperate deciduous forest biome: cold winters, arm summers, moderate rainfall, trees that shed leaves, animals like deers foxes and birds
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What are characteristics of the temperate coniferous forest biome?
Temperate coniferous forest biome: Forests are cold, dry, more trees that don't shed leaves and conserve water, animals like beavers and bears and birds
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What are characteristics of the taiga biome?
Taiga biome: Less rainfall than temperate forests, have long cold winters, have trees that do not shed, soil covered in moss, moose and deer found and some birds/rodents
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What are characteristics of the tundra biome?
Tundra biome: Treeless, frozen plain, snow and ice (permafrost), short summer
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What are characteristics of the polar biome?
Polar region: frozen with no vegetation, few terrestrial animals, little precipitation
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What are the types of aquatic biomes? Describe each of them
- Marine biomes: relatively constant amount of nutrient materials and dissolved salts
- Freshwater biome: strong currents so more wish with strong muscles and plants with root-like holdfasts, affected by variations in climate and water (not like marine)
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What are zones of the marine biomes?
-Intertidal zone: region exposed at low tides undergoing variations in temperature and periods of dryness, crabs, clabs, snails sponges live here
-Neritic zone: region on continental shelf hundred miles from shore, have fish, crustaceans and crabs
-Pelagic zone: Open sea and is divided into photic and aphotic zones
————-Photic zone: sunlit layer of sea from 250-600 ft deep, has plankton, nekton, and diatom (algae)
————-Aphotic zone: region below photic zone with no sunlight, only heterotrophs present
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What is the biosphere?
Biosphere: made of atmosphere, lithosphere (rock and soil) and the hydrosphere (oceans)
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What does poikilothermic mean?
Cold Blooded/ poikilothermic -> body temperature is close to that of surroundings because most heat energy escapes to environment
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What does homeothermic mean?
Warm blooded/ homeothermic -> evolved physical mechanisms for thermoregulation that allow them to make use of the heat produced as a consequence of respiration, constant body temp. Is higher than temp. of environment
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What is soil affected by?
Soil is affected by acidity, pH, texture, minerals and humus quantity (amount of decaying plant and animal life in soil)
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What are autotrophs and what are the types?
- Autotrophs -> organisms that manufacture their own food
- Phototrophs use energy from sun to manufacture food
- Chemotrophs obtain energy from oxidation of inorganic compounds
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What are heterotrophs?
Heterotrophs cannot make their own food and depend on autotrophs or other heterotrophs to obtain food and energy
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What has shorter digestive tracts: carnivores or herbivores?
Carnivores have shorter digestive tracts than herbivores
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What are the major types of interspecific interactions?
Major types of interspecific interactions: Symbiosis, predation, saprophytism, and scavenging
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What are the types of symbiosis?
- Commensalism: One organism is benefited and the other is not affected
- Mutualism: Both organisms derive some benefit
- Parasitism: A parasite benefits at the expense of the host
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What are ectoparasites and endoparasites?
Parasites can be ectoparasites and stick to exterior surface of host or be endoparasites and live within the host
275
What are saprophytes?
Saprophytes: Protists and fungi that decompose (digest) dead organism matter externally by secreting digestive enzymes and then absorbing the nutrients
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What are scavengers?
Scavengers are animals that consume dead animals
277
What do food chains show?
Food chains show the transfer of energy and each step is a trophic level
278
What are primary producers?
Primary producers: initial step in food chain, use energy to manufacture carbohydrates, proteins and lipids
279
What are primary consumers?
Primary consumers: animals that consume plants (herbivores)
280
What are secondary consumers?
Secondary consumers: Animals that consume the primary consumers (carnivores)
281
What are tertiary consumers?
Tertiary consumers: Animals that feed on secondary consumers (carnivores)
282
What are decomposers
Decomposers: break down organic wastes and dead tissues to simpler compounds to be used again
283
What is the food web?
- Food web is interconnected food chain
| - The greater the number of pathways in a community food web, the more stable the community
284
What is the nitrogen cycle?
Nitrogen Cycle: elemental nitrogen is chemically inert and cannot be used by most organisms, lightning and nitrogen fixing bacteria change the nitrogen to usable and soluble nitrates
285
What are the domains?
3 domain are archaea, bacteria and eukarya
286
What are the kingdoms?
6 kingdoms are Archaea, eubacteria, protista, fungi, plantae, and animalia
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What are characteristics of monera?
- Monera (Archaea and Eubacteria):
- Prokaryotes, lack a nucleus or membrane bound organelles, single-celled organisms that reproduce asexually
- Can exist as aggregates of cells that stick together after division
- Was split into eubacteria and archaea
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What are eubacteria and characteristics of them?
Bacteria are usually single-celled prokaryotes with single double stranded loop of DNA not enclosed in membrane, usually have cell walls
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What is Cyanobacteria and what are their characteristics?
- Types of bacteria that normally live in freshwater, but also marine environments
- Have a cell wall and photosynthetic pigments but no flagella, true nuclei, chloroplasts or mitochondria
- Can withstand extreme temperatures
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What are the characteristics of archaea?
- Prokaryotes, usually have cell wall and flagella
- Cell membranes are made with glycerol-ether lipids
- Inhabit extreme areas (temperature and pH)
291
What is Protozoa?
Protozoa are single celled organisms that are heterotrophic (like amoebas)
292
How do slime molds arrange and reproduce?
Slime molds are arranged in a coenocytic (many nuclei) mass of protoplasm and reproduce asexually via sporulation
293
What are the characteristics of protista?
- Membrane bound nuclei and organelles
- Either single cells or colonies of similar cells with no differentiation
- Includes protozoa and algae
294
What are the characteristics of fungi?
Eukaryotic, multicellular, differentiated and non motile
- Cell wall made of chitin
- Heterotrophs, can be saprophytic (decompose dead organic material like bread mold) or parasitic (athlete's foot)
- Fungi absorb food from their environment
- Reproduce by asexual sporulation or by intricate sexual processes
295
What are characteristics of plantae?
- Multicellular, differentiation of tissues, nonmotile, photosynthetic
- Make their own energy -> autotrophs
296
What is the structure of most plants?
- Absorptive tissues like roots and rhizoids project into soil to absorb water and minerals
- Conducting or vascular tissues include specialized tubes that transport water minerals and nutrients to all parts of the plant
- Cuticles minimize water loss and permit the transmittance of light
297
What are bryophytes and what are their characteristics?
- Bryophyta, hepatophyta and anthocerotophyta are simple plants with few specialized organs and tissues
- They lack the water conducting woody material (xylem) that functions as support
- The gametophytes the dominant generation and is the main plant and is larger and nutritionally independent
- The sporophyte is smaller and short-lived, growing off the gametocyte from the archegonium
- Mosses are classic bryophytes in which the sporophyte and gametophyte grow together
298
What are tracheophytes and what are their characteristics?
- Vascular plants are complex plants with a degree of cell differentiation
- They have vascular tissues -> xylem (water-conducting) and phloem (food-conducting)
- Have radial symmetry and anchored by deep roots
- Have waxy surfaces for water conservation and stomata for gas exchange
- Sporophyte generation is dominant, gametophyte is short-live and either independent or small and parasitic
299
What are the 2 extant divisions of non-seed-bearing vascular plants?
Two extant divisions of non-seed-bearing vascular plants: Pteriodphyta and Lycophyta
300
What are the characteristics of pterophytes?
Pterophytes of the division of pteridophyta include ferns and grow from underground stems called rhizome and have large leaves and many vascular bundles, grow in length not diameter and have xylem with elongated tracheid cells that transport water and salts, don't produce seeds
301
What are characteristics of lycophytes?
Lycophytes have roots, are non woody and contain microphyll leaves (e.g. club mosses)
302
What are angiosperms and what are their characteristics?
- Contains the greatest number of different plant species of all the extant plant divisions
- Have covered seeds and are the most abundant, have flowers not cones as primary reproductive structure
- The anther of the male stamen produces microspores (pollen grains), while the ovary of the female pistil produces megaspores
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What are dicotyledons?
Dicotyledons (Dicots): angiosperms with net-veined leaves and vascular bundles around a ring within the central cylinder, contain 2 cotyledons (seed leaves) within the seed, can be woody and have flower parts in multiples of 4 or 5, examples are maple and apple trees
304
What are monocotyledons and their characteristics?
Monocotyledons (monocots): angiosperms that contain leaves with parallel veins, scattered vascular bundles and seeds with single cotyledons, nonwoody, have flower parts in multiples of 3, examples are grasses (wheat, corn, rice) and sugar cane, pineapple, bananas, palms
305
What are gymnosperms and what are their characteristics and what are some examples of them?
- Naked seeded plants, pollen can be carried by wind, sperm nuclei fertilize the egg with the aid of a pollen tube and the embryo develops within the exposed seed
- Presence of a specialized cambium tissue allows for secondary growth of secondary xylem (wood) and secondary phloem, can grow in diameter and length, are woody
- Most gymnosperms are evergreens (non-deciduous)
- Conifers are the largest grouping of gymnosperms: include pines, spruce and firs, have cones and modified leaves, have large female cones that produce megaspores and small male cones that produce microspores
- Cycads, gnetophytes and ginkgo are also gymnosperms
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What are characteristics of animalia?
- Multicellular, usually motile, heterotrophic and have differentiated tissue
- Can have bilateral or radial symmetry
307
What are porifera?
Porifera: sea sponges with 2 layers of cells, pores
308
What are cnidaria?
Cnidaria: have digestive sac that is sealed at one end (gastrovascular cavity), 2 layers- ectoderm and endoderm, can have tentacles and stinging cells, examples: jellyfish and coral
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What are platyhelminthes?
Platyhelminthes: Flatworms with ribbon like bilaterally symmetrical bodies, 3 layers of cells, no circulatory system
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What are nematoda?
Nematoda: roundworms with long digestive tubes and anuses, no circulatory system, e.g. hookworms
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What are annelida?
Annelida: Segmented worms that possess a coelom (true body cavity), has circulatory system and excretory and nervous, e..g earthworms and leeches
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What are characteristics of mollusca?
Mollusca: Soft bodied, calcium carbonate exoskeletons, breath by gills and have chambered hearts, e.g clam, snail and squid
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What are Arthropoda and what are the classes?
Arthropoda: Jointed appendages, chitinous exoskeleton, open circulatory systems, 3 important classes- insects, arachnids and crustaceans,
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What is echinodermata?
Echinodermata: spiny, radially symmetrical, have water vascular system, e.g. starfish and sea urchins
315
What are characteristics of chordata?
Chordata: Stiff dorsal rod called notochord, tails, vertebrata is subdivision of chordata that includes amphibians, reptiles, birds, fish and mammals
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What are agnatha?
Agnatha: Jawless fish, eel-like, sucking mouth
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What are chondrichthyes?
Chondrichthyes: Cartilaginous fish with jaws and teeth, e.g. shark
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What are osteichthyes?
Osteichthyes: Bony fish, have scales, lack notochord in adult form e.g. tuna
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What are characteristics of amphibia?
Amphibia: use external fertilization, have larval stages in water and adult stages on land, e.g. frogs
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What are characteristics of reptilian?
Reptilia: Terrestrial animals, breath by lungs, internal fertilization, lay eggs, coldblooded, have scales e.g. turtle
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What are ave?
Ave: Birds with 4 chambered hearts and are warm blooded, eggs surrounded by shells e.g. hen and eagle
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What are characteristics of mammalia?
Mammalia: Animals that are warm blooded and feed their offspring with milk, monotremata (platypus), marsupialia and placentalia
323
What are characteristics of viruses?
Considered nonliving, either RNA or DNA, have lytic or lysogenic life cycles
