process by which some organisms capture the energy from the sun (solar) and transform it into energy (chemical) that can be used by living things
an organism that makes its own energy-rich food components using the sun's energy. ex.) green plants
- organisms that make their own food
Phototroph: use solar energy (photosynthesis) to get energy
Chemotroph: use different chemical processes to get energy
- an organism that obtains its energy from consuming other organisms
- organism that must take in food to meet their energy needs
- consume autotrophs, other heterotroph (carnivores), or both (omnivore)
- a huge asteroid is thought to have hit Earth near Mexico which sent up so much dust that the sun was blocked for many years
No sun = no food = no dinos
- regions on the surface of the Earth and atmosphere where living organisms exist
1. Light reactions (in thylakoid membranes): light is absorbed by chlorophyll and converted to ATP and NADPH
2. Dark reactions(Calvin cycle) (in stoma): ATP and NADPH used to drive the synthesis of carbohydrates
internally in the leaves, in the mesophyll
TRUE
PSI - discovered first
PSII - in 1st step of photosynthesis
- to make NADPH
Oxygen, NADPH, ATP
- a zigzag shape of energy curve
- photosynthesis involves increases and decreases in the energy of an electron as it moves from PSII through PSI to NADPH
- involves light exciting electrons
- creating carbohydrates through the calvin cycle
- CO2 is incorporated
- requires massive input of energy
- product is glyceraldehyde-3-phosphate (G3P) (made into glucose later)
- 3 phases: Carbon fixation, reduction and carbohydrate production, regeneration of RuBP
TRUE
- in warm dry climates C4 plants conserve water and prevent photorespiration
- evolved a mechanism to minimize photorespiration
ex.) Bamboo, corn
Crassulacean acid metabolism
- separate processes using time
- open stomata at night
- CO2 enters and is converted to malate
- banks up on CO2 throughout the day to convert it at night
ex.) Cactus
= the acquisition of traits by their transmission from parent to offspring
- used to have thought to occur through pangenesis (whole body contributes to offspring)
that hereditary traits blended together in offspring and continued to be passed down
- not true either!!
- priest
- studied physics and math
- studied pea plants
- "father of modern genetics"
1. Genetic variation
2. Normally self-fertilizing
3. Ease of making crosses
P gen: true-breeding parents
F1 gen: first-generation offspring of a P cross
F2 gen: F1 monohybrids fertilize to produce the F2 generation
1. Traits may exist in two forms, dominant and recessive
2. An individual carries 2 genes for a character/trait, genes have different alleles
3. 2 alleles of a gene separate to give rise to haploid cells and gametes, so each sperm and egg receives only one allele
2 copies of a gene segregate from each other during gamete formation, so only one allele is given to each gamete
Genotype: genetic composition of individual
Phenotype: characteristics (traits) of an organism that are the result of their genotype ex.) Tall phenotype vs. dwarf phenotype
1. Linked assortment: genes segregate together
2. Independent assortment: genes are independent, so their alleles are randomly distributed into the gametes, ex.) 9:3:3:1
Mendel saw Independent assortment
the alleles of different genes assort independently of each other during the process that gives rise to gametes
Autosomes: pairs of chromosomes found in both sexes
Sex chromosomes: distinctive pair of chromosomes that differs between males and females
- 46 chromosomes
- 22 pairs of autosomes
- 1 pair of sex chromosomes
Wild-type allele: prevalent allele in a population
Mutant allele: alleles that have been altered by mutation (rare in natural populations)
- heterozygote exhibits a phenotype that is distinct and intermediate between the two homozygous phenotypes
- shows different phenotypes at 100%, 50% and 0% protein levels
- red, white, and pink
- single individual expresses both alleles in a way that leads to BOTH traits in the phenotype
- determined by multiple genes!
- traits that show continuous variation over a range of phenotypes are called quantitative traits
ex.) grain pigmentation in wheat
TRUE
- the gene for coat colour is on the X chromosome
- shows patches where the orange or black allele was inactivated
gene linkage = when different genes are close together on the same chromosome, they tend to be transmitted as a unit
linkage group = group of genes that usually stays together during meiosis (do NOT follow the law of independent assortment)
Noncombinants: offspring combination of traits has not changed from parental generations (no crossing over between genes)
Recombinants: offspring have a different combination of traits from parental generation (crossing over occurs)
10 to 50 trillion cells
1. Mitosis
2. Meiosis
The field of genetics involving microscopic examination of chromosomes
TRUE
- a photographic representation of chromosomes
Diploid: 2 chromosome sets (2N)
Haploid: 1 set of chromosomes (N)
FALSE, chromosome X is much bigger than Y
Interphase
G1: first gap
S: synthesis of DNA
G2: second gap
M: mitosis & cytokinesis
Mitosis = division of one nuclei into two nuclei
Cytokinesis = division of one cell into two
Animal cells: cleavage furrow constricts (like a drawstring) to separate cells into two
Plant cells: vesicles from Golgi apparatus form a cell plate, which then forms a cell wall between the 2 daughter cells
TRUE
= the connection between chromosomes that have crossed over (visible during late prophase)
Boveri & Sutton
physical location of a gene on a chromosome
TRUE
the "blueprint" for the construction of living organisms
1. Information
2. Replication
3. Transmission
4. Variation
PROTEIN
Griffith
1. Smooth (S): secretes a capsule, look smooth
= pathogenic: causes disease/infection and kils mice
1. Rough (R): does not secrete a capsule, look rough
= does not cause infection in mice
Avery, MacLeod, and McCarty
A process in bacteria where DNA is taken up from the environment and incorporated into the cell
- can be performed naturally and also be induced
A complete complement of an organism's genetic material
1. Phosphate group
2. Pentose sugar = Deoxyribose
3. Nitrogenous bases
Purines: Adenine, Guanine
Pyrimidines: Cytosine, Thymine
James Watson, Francis Crick, Maurice Wilkins
Rosalind Franklin
a) Semiconservative mechanism: 1 parental strand and one newly made daughter strand
b) Conservative mechanism: 2 new daughter strands
c) Dispersive mechanism: segments of new DNA are interspersed with the parental DNA
Semiconservative model
Stahl & Meselson
In DNA replication, 2 PARENTAL strands separate and serve as template for synthesis of new strands. New nucleotides are added according to BASE-PAIRING rules
Result is 2 DOUBLE helices, and each double helix has ONE parental strand and ONE newly made daughter strand.
Bacteria - single origin of replication (think circle)
Eukaryotes - multiple origins of replication
DNA helicase
DNA topoisomerase
DNA polymerase
TRUE, has two consequences:
- Cannot begin DNA synthesis on a bare template strand
- DNA synthesis always proceeds in a 5’ to 3’ direction
- initiates DNA synthesis by making a short segment of DNA (called RNA primer)
= true
Leading strand:
- a single RNA primer is made
- synthesis of DNA is continuous from the primer, making one long molecule
- synthesis occurs in SAME direction as fork movement
Lagging strand:
- synthesis occurs in OPPOSITE direction to fork movement
- requires multiple RNA primers
- SHORT segments of DNA are synthesized
Okazaki fragments
DNA ligase = connects the newly synthesized DNA to the other parts of DNA -> used to seal DNA fragments of lagging strand
TRUE
TRUE
process by which the information of a gene is made into a functional product
a heritable change in the genetic material - can alter gene sequence
Archibald Garrod studied patients with metabolic defects such as alkaptonuria (black skin, cartilage, urine)
a group of rare genetic disorders that affect the body's ability to convert food into energy:
- studied common bread mold
- they had a ONE GENE ONE ENZYME theory
- discovered that enzymes are only one category of cellular proteins -> genes encode for other types
- some proteins are composed of two or more polypeptides
Watson & Crick
Prokaryotes:
- no nucleus
- smaller
- DNA in cytoplasm
Eukaryotes:
- has nucleus
- more complex
- bigger
- DNA in nucleus
an organized unit of DNA sequences
- transcribed into RNA
- results in the formation of a functional product
tRNA = transfer RNA
rRNA = ribosomal RNA
Promoter: section that brings in RNA polymerase to start the transcription - signals the beginning of transcription
Terminator: boots RNA polymerase off - signals the end of transcription
Regulatory sequence: site for binding of regulatory proteins
- can increase/decrease the rate of transcription
Transcribed region: this region contains the info that specifies an amino acid sequence
TRUE
1. Initiation
2. Elongation/synthesis of the RNA transcript
3. Termination
Template/noncoding strand: the DNA strand used as a template for RNA synthesis
Coding strand: DNA strand NOT used for transcription
- Unlike DNA polymerase:
- RNA polymerases can start on a template WITHOUT A PRIMER (but still uses 3' OH to link the strands)
- RNA polymerases DO NOT proofread and have no exonuclease activity
Capping: a different nucleotide gets added to the 5' end (as soon as RNA starts coming out) = 5' cap (protects mRNA)
Tailing: increases mRNA stability, aids in export from nucleus = poly A tail
Splicing: removing introns from the transcript and joins exons together
- catalyzed by the spliceosome
snRNPs form the core of the spliceosome
- are made of snRNA & proteins
1. A site = aminoacyl site
2. P site = peptidyl site
3. E site = exit site
APE = the direction that the tRNA goes in when translation occus
Biomembrane that separates the internal contents of a cell from its external environment
- Regulates the traffic of substances into and out of the cell
- Provides an interface to carry out many vital cellular activities
Plasma membrane is a MOSAIC of lipid, protein, and carbohydrate.
1. Transmembrane proteins
2. Lipid-anchored proteins
3. Peripheral membrane proteins
1. Length of phospholipid tails (shorter vs. longer can affect the stiffness of the membrane)
2. Double bonds in phospholipid tails
3. Presence of cholesterol (can increase and decrease fluidity)
Shorter lipid tails interact LESS with each other, making the membrane MORE fluid.
Double bonds create KINKS in the lipid tails = unsaturated fatty acids
This REDUCES interactions between adjacent tails, making bilayer MORE fluid
At higher temperatures, cholesterol makes membrane LESS fluid (liquid is disordered)
• At lower temperatures, cholesterol makes membrane MORE fluid (liquid is ordered)
movement of water across membranes in response to solute concentration gradients
- helpful when the solute cannot cross membrane to reach equilibrium so the water will move
Crenation = cell shrinkage
Lysis = cell swelling
TRUE, channels are very quick
1. Uniporters - single ion/molecule transported
- ONE DIRECTION
2. Symporters - two or more diff types transported
- BOTH IN SAME DIRECTION
3. Antiporters - two or more diff types transported
- OPPOSITE DIRECTIONS (one in, one out)
Transporters that uses energy sources to change conformation are also called PUMPS.
Direct energy = primary active transport
Pre-existing gradient = secondary active transport
an electrogenic pump
- generates an electrical gradient
- net export of 1 positive charge (3 out 2 in)