Biomolecules and Enzymes 1. Macromolecules a. Large complex molecules (polymer) made up of repeating subunits (monomers) b. Carbohydrates (polysaccharide) i. Elements: carbon, hydrogen, and oxygen (1:2:1 ratio, therefore #C = #O) ii. Subunit/monomer: monosaccharide (sugar) iii. Examples: fruits/veggies, bread/pasta, cellulose in plants, glucose iv. Used for immediate (short-term) energy c. Lipids i. Elements: carbon, hydrogen, and oxygen (#C ≥ #O) ii. Subunit/monomer: fatty acid chains and glycerol iii. Examples: fats (butter), oils, and waxes iv. Uses – long term energy storage (keeps your warm) & phospholipid bilayer d. Proteins (polypeptide) i. Elements: carbon, hydrogen, oxygen , nitrogen (and sometimes sulfur) ii. Subunit/monomer: amino acids connected with peptide bonds iii. Examples: meat, eggs, fish, nuts, beans, enzymes iv. Uses – enzymes (speed up chemical reactions), regulation of reactions, & transport of molecules e. Nucleic Acids i. Elements: carbon, hydrogen, oxygen, nitrogen, and phosphorous ii. Subunit/monomer: nucleotides iii. Examples: DNA and RNA iv. Uses – store and transmit genetic information f. Pictures of the 4 biomolecules g. Formation of polymers – Dehydration Synthesis (water removed to bind 2 monomers together) h. Breakdown of polymers – Hydrolysis (water added to break the bonds of a polymer to divide into its monomers) 2. Enzymes (catalysts) a. Proteins that speed up chemical reactions b. Remain unchanged by the reaction, do not get used up c. Work by lowering activation energy (minimum energy needed for a chemical reaction to occur) d. They have a specific shape, which determines which substrate they work with (lock-and-key) Specificity = only one substrate can bind with one enzyme in the active site e. Substrates bind to the enzymes active site; the enzyme “hugs” the substrate – induced fit
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Biomolecules and Enzymes 1. Macromolecules
a. Large complex molecules (polymer) made up of repeating subunits (monomers)
b. Carbohydrates (polysaccharide)
i. Elements: carbon, hydrogen, and oxygen (1:2:1 ratio, therefore #C = #O)
ii. Subunit/monomer: monosaccharide (sugar)
iii. Examples: fruits/veggies, bread/pasta, cellulose in plants, glucose
iv. Used for immediate (short-term) energy
c. Lipids
i. Elements: carbon, hydrogen, and oxygen (#C ≥ #O)
ii. Subunit/monomer: fatty acid chains and glycerol
iii. Examples: fats (butter), oils, and waxes
iv. Uses – long term energy storage (keeps your warm) & phospholipid bilayer
d. Proteins (polypeptide)
i. Elements: carbon, hydrogen, oxygen , nitrogen (and sometimes sulfur)
ii. Subunit/monomer: amino acids connected with peptide bonds
iii. Examples: meat, eggs, fish, nuts, beans, enzymes
iv. Uses – enzymes (speed up chemical reactions), regulation of reactions, & transport of molecules
e. Nucleic Acids
i. Elements: carbon, hydrogen, oxygen, nitrogen, and phosphorous
ii. Subunit/monomer: nucleotides
iii. Examples: DNA and RNA
iv. Uses – store and transmit genetic information
f. Pictures of the 4 biomolecules
g. Formation of polymers – Dehydration Synthesis (water removed to bind 2 monomers together)
h. Breakdown of polymers – Hydrolysis (water added to break the bonds of a polymer to divide into its
monomers)
2. Enzymes (catalysts)
a. Proteins that speed up chemical reactions
b. Remain unchanged by the reaction, do not get used up
c. Work by lowering activation energy (minimum energy needed
for a chemical reaction to occur)
d. They have a specific shape, which determines which substrate
they work with (lock-and-key) Specificity = only one substrate
can bind with one enzyme in the active site
e. Substrates bind to the enzymes active site; the enzyme “hugs”
the substrate – induced fit
Cell Structures and Functions
1. Cell Theory
a. All living things are composed of cells
b. Cells are the basic unit of structure and function in living things (cell = smallest unit capable of
performing life functions)
c. All cells come from preexisting cells through mitosis
2. Levels of Organization (small to large): atom molecule/compound organelle cell tissue organ
organ system organism population community ecosystem
3. Prokaryote vs. Eukaryote Cells
a. Similarities (DR.CC)
i. DNA – instructions for life
ii. Ribosomes – make protein
iii. Cytoplasm – protects
iv. Cell membrane – controls in/out (homeostasis)
b. Differences
Prokaryotic Eukaryotic
*Simple *Complex
*Unicellular *Unicellular OR multicellular
*NO membrane-bound organelles
*DO have membrane-bound organelles
*Reproduction via binary fission
*Reproduction via mitosis & meiosis
*Bacteria *Protists, fungi, plants, and animals
4. Organelle Structures and Functions (organelles are small structures that perform various functions for the cell)
a. Cell Wall
i. Found in bacteria, fungi, and plants (outside the cell membrane)
ii. Supports and protects cells
b. Cell Membrane
i. Double layer of lipids and protein that surrounds ALL cells
ii. Controls movement into and out of the cell (semi-permeable); therefore, controls homeostasis
c. Cytoplasm: Gel-like mix (80% water) that protects the organelles
d. Nucleus - Controls cell activities and contains the genetic material (DNA)
e. Mitochondria – Produces ATP (energy) by cell respiration
f. Rough ER – covered with ribosomes; transports proteins to Golgi
g. Smooth ER – Makes steroids/ions and transports the to the Golgi; detoxifies poisons and drugs
h. Ribosomes – make protein
i. Golgi – modifies, sorts, and packages molecules from the ER and distributes them with vesicles
j. Lysosome – has digestive enzymes that break down wastes and old cell parts
k. Vacuole – stores water, food, and wastes; maintains the shape of plant cells (turgor pressure)
l. Chloroplasts – make food (glucose) out of sun energy for plants
Cell Transport
5. Cell Transport
a. Homeostasis: maintaining a stable body system. Maintained by the cell membrane
b. Cell membrane is selectively (semi)permeable – lets some things in/out but not others
c. Concentration gradient – A high concentration of molecules in one area, spreading out to a low
concentration of molecules in another area
d. Passive Transport – the movement of molecules DOWN/WITH their concentration gradient without
using energy (from high to low concentration)
i. Diffusion: movement of small molecules from high to low concentration
ii. Facilitated Diffusion: movement of small molecules from high to low with the help of proteins
iii. Osmosis: movement of water molecules from high to low concentration
e. Active transport – movement of molecules UP/AGAINST their concentration gradient, which requires
energy (from low to high concentration) – requires ATP
i. Transport proteins – carry molecules across the membrane
ii. Endocytosis and exocytosis (entering and leaving the cell in vesicles)
f. Osmotic solutions
i. Isotonic
1. Solution has same amount of “stuff” and water
2. No net movement of water
3. Cell stays the same (true for plant AND animal cells)
ii. Hypertonic
1. Solution has lots of “stuff” and not much water
2. Net movement of water OUT of the cell
3. Cell shrivels (true for plant AND animal cells)
iii. Hypotonic
1. Solution has lots of water and not much “stuff”
2. Net movement of water INTO the cells
3. Animal cells swell and burst (no cell wall to support)
4. Plant cells display good turgor pressure
Photosynthesis and Cellular Respiration 1. How Do Cells Obtain Energy?
a. Types of organisms
i. Heterotrophs – must eat food to get energy
ii. Autotrophs – make their own food
b. ALL energy in living organisms comes from the sun (food pyramid)
2. Cellular Respiration (turns food into ATP energy)
a. Occurs in ALL eukaryotic organisms (protists, fungi, plants, animals) since they all need energy to survive
b. Organelle: mitochondria
c. BREAKS glucose down to release chemical energy (ATP)
d. C6H12O6 + 6O2 6H2O + 6CO2 + 36/38 ATP (energy) e. Aerobic respiration (aerobic = needs oxygen) occurs in the mitochondria – makes 34/36 ATP
f. Anaerobic respiration (no oxygen present) occurs in the cytoplasm – makes 2 ATP
i. Alcoholic Fermentation - occurs in plants and fungi (yeast)
ii. Lactic Acid Fermentation - occurs in animals (causes pain in muscles after a workout)
g. Energy source = glucose (chemical food energy); Energy product = ATP (chemical energy)
3. Photosynthesis (turns sunlight into food)
a. Occurs in plants and some protists (everyone else has to eat their food)
b. Organelle: chloroplast
c. Sunlight = radiant energy
d. Uses radiant energy to MAKE glucose
e. 6CO2 + 6H2O + sunlight C6H12O6 + 6O2 f. Beginning of all food chains – so ALL life is supported by photosynthesis
g. Energy source = sunlight (radiant energy); Energy product = glucose (chemical food energy)
h. Structure of leaves
i. Stomata – pores on the underside of leaves that let gases move in and out. Open during the day
and usually closed at night
ii. Xylem – moves water up to the leaves from the roots
iii. Phloem – moves glucose down to the rest of the plant from the leaves
i. What affects photosynthesis
i. Light intensity – the more light, the faster the rate of photosynthesis (to a point)
ii. Carbon dioxide – the more CO2, the faster the rate of photosynthesis (to a point)
iii. Temperature – if it is too high or too low, the rate drops
*The products of respiration are the reactants
of photosynthesis
*The reactants of photosynthesis are the
products of respiration
Cell Cycle 1. Cell Cycle and Mitosis
a. Cells divide so we can grow, repair damaged cells, and replace old cells (GRR – growth, repair, & replace)
b. Chromosomes
i. Humans have 46 total chromosomes - 23 chromosomes from each parent
ii. When DNA is loose it is called chromatin (like this during interphase and resting), when it is
coiled, it is called a chromosome (like this during mitosis); chromosomes have an “X” shape
c. Cell division in prokaryotes (bacteria) is called binary fission
d. Cell Cycle in eukaryotes
i. Interphase
1. G1 – first growth phase
2. **S – synthesis (DNA replicates)**
3. G2 – second growth phase
ii. Mitosis – 4 stages (PMAT)
1. Prophase
a. DNA condenses into chromosomes
b. Nuclear membrane breaks down
c. Spindle fibers form
2. Metaphase
a. Spindle fibers attach to the chromosomes
b. Chromosomes move to the equatorial plate (middle of cell)
3. Anaphase
a. Spindle fibers pulls sister chromatids to opposite ends of the cell
4. Telophase
a. Chromosomes de-condense
b. Two new nuclear membranes form
c. Spindle fibers break down
iii. Cytokinesis
1. Division of the cytoplasm; occurs after mitosis is complete
2. Daughter cells of mitosis: two genetically identical cells – same number of chromosomes
as each other and as the parent cell
e. Problems with mitosis
i. If cells do not rest, and stay in the cell cycle dividing uncontrolled, cancer occurs
ii. Cell become cancer if they skip checkpoints
iii. Cancer cells do NOT go into G0 (resting phase)
DNA Structure and Replication 1. DNA Structure and Replication
a. History of DNA – 1950s
i. Rosalind Franklin used X rays to photograph DNA
ii. James Watson and Francis Crick used photograph to determine DNA is a double helix
b. Structure of DNA
i. DNA is made of the biomolecule nucleic acids, which are made up of the monomer nucleotides
ii. Nucleotides – made of a phosphate group, sugar (deoxyribose), and one of 4 nitrogenous bases
iii. Backbone is made of sugar and phosphate groups, connected by phosphate bonds. The function
is to provide double-helix structure and support
iv. The middle is made of the nitrogen bases (adenine, thymine, guanine, and cytosine) connected
by hydrogen bonds
1. A always pairs with T (2 hydrogen bonds)
2. G always pairs with C (3 hydrogen bonds)
v. *The sequence of the nitrogen bases is what determines your traits and characteristics (you
use the sequence to build proteins)
c. Why is DNA Important?
i. Gene = specific sequence of bases
ii. 20-30 thousand genes per chromosome (46 chromosomes, or 23 pairs, per person)
iii. ALL body cells contain a complete copy of your ENTIRE genome (all your genes) – cells do
different things because they turn on different genes depending on their job
iv. ***ALL living organisms contain DNA, and the DNA for all is made out of the same things. Only
difference is the sequences of bases***
2. DNA Replication
a. Occurs during the S stage of interphase during the cell cycle
b. The enzyme helicase breaking the hydrogen bonds holding the nitrogen base pairs together
c. The two sides of the DNA separate to be used as template strands
d. The enzyme DNA polymerase adds new nitrogen bases to the template strands
e. End result is two identical pieces of DNA, each with one old strand and one new strand
f. This kind of replication is known as semi-conservative (one old strand + one new strand)
PROTEIN SYNTHESIS
3. DNA vs. RNA
a. DNA is double stranded; RNA is single-stranded
b. DNA has thymine; RNA has uracil
4. Messenger RNA (mRNA) – copies DNA code & carries the info from nucleus to ribosomes
5. Genetic Code
a. Ribosomes read the mRNA nucleotides in groups of 3 bases (3 bases = codon)
6. Steps of protein synthesis
a. Step One – Transcription
i. Occurs in the nucleus
ii. DNA strand (template strand) mRNA
1. T A A U
2. G C C G
iii. mRNA leaves the nucleus through the nuclear pores and goes to the ribosome (floating in
cytoplasm or attached to rough ER)
b. Step Two – Translation
i. Occurs at a ribosome
ii. The process of decoding mRNA and turning it into a polypeptide chain (protein)
iii. End Product: A protein in its primary structure (string of amino acids bonded by peptide bonds)
7. Gene Expression
a. Every body cell has a full set of DNA (46 chromosomes), but different cells do different things
b. Each cell only turns on the genes it needs to do its job
c. Gene expression can be influenced by: the environment, hormones, and chemicals
MUTATIONS
1. Mutation means change
2. Types
a. Substitution – one nucleotide is replaced with another
i. This is a type of point mutation (only affecting a single nucleotide)
ii. Total number of bases stays the same
iii. Types
1. Silent – Same amino acid
2. Missense –Different amino acid
3. Nonsense –STOP codon (no amino acid)
iv. Frameshift mutations
1. Causes changes in ALL codons that come after the mutation
2. Total number of bases either increases or decreases
3. Types
a. Deletion – a nucleotide is taken out completely
b. Insertion – an extra nucleotide is added to the sequence
POINT MUTATIONS FRAMESHIFT MUTATIONS
MEIOSIS
1. Basis for sexual reproduction
2. Similar to mitosis, but division happens twice
3. Starts with one cell that has 46 single-stranded chromosomes
4. Results in 4 cells that each have half the amount of genetic information – 23 chromosomes
5. For humans, these are egg and sperm cells (gametes)
6. Starts with Interphase (just like mitosis), during which the cell grows and DNA doubles.
7. Occurs in 2 phases – Meiosis I and Meiosis II (this is known as reduction-division)
8. Meiosis I
a. Prophase I – chromatin condenses into chromosomes and homologs pair up (called tetrads) and nuclear
membrane breaks down. Crossing over occurs (pieces of chromosomes or genes are exchanged between
the tetrads) to increase genetic variation in offspring
b. Metaphase I – Spindle fibers attach to the double banded chromosomes and push them to the middle of
the cell (equatorial plate)
c. Anaphase I – homologous chromosomes separate and move to opposite pole
d. Telophase I – two nuclear envelopes reassemble and cytokinesis divides the cell in two
9. Meiosis II
a. Prophase II – the nuclear membranes break down and spindle fibers form
b. Metaphase II chromosomes to the equator of the cell
c. Anaphase II – Sister chromatids are ripped apart and moved to opposite poles
d. Telophase II – four new nuclear envelopes form, the and cytokinesis divides both cells in two (ends with
4 cells)
GENETICS
1. Meiosis – basis for sexual reproduction
a. Similar to mitosis, but division happens twice
b. Results in 4 cells that each have half the amount of genetic information (n = haploid) – 23 chromosomes
c. For humans, these are egg and sperm cells (gametes)
d. Starts with Interphase (just like mitosis), during which the cell grows and DNA doubles. For humans, that
means 46 chromosomes double to 92 chromosomes
e. Occurs in 2 phases – Meiosis I and Meiosis II (this is known as reduction-division)
f. Meiosis I
i. Prophase I – chromatin condenses into chromosomes and homologs pair up (called tetrads) and
nuclear membrane breaks down. Crossing over occurs (pieces of chromosomes or genes are
exchanged between the tetrads) to increase genetic variation in offspring
ii. Metaphase I – Spindle fibers attach to the double banded chromosomes and push them to the
middle of the cell (equatorial plate)
iii. Anaphase I – homologous chromosomes separate and move to opposite pole
iv. Telophase I – two nuclear envelopes reassemble and cytokinesis divides the cell in two
g. Meiosis II
i. Prophase II – the nuclear membranes break down and spindle fibers form
ii. Metaphase II chromosomes to the equator of the cell
iii. Anaphase II – Sister chromatids are ripped apart and moved to opposite poles
iv. Telophase II – four new nuclear envelopes assemble, chromosomes decondense, the and
cytokinesis divides both cells in two
2. Genetics
a. Terminology
i. Trait – any characteristic passed from parent to offspring
ii. Heredity – passing of traits from parents to offspring
iii. Genetics – the study of heredity
iv. Genes – control the expression of traits
v. Alleles – two forms of a gene (can be dominant or recessive)
vi. Dominant allele – the stronger of two alleles, covers up the recessive if present, and is
represented by a capital letter
vii. Recessive allele – the weaker of two alleles that only shows up if the organism has two copies,
represented by a lowercase letter
viii. Genotype – the genetic combinations for a trait (the letters)
ix. Phenotype – the physical feature resulting from the genotype (what the organism LOOKS like)
x. Homozygous –two of the same alleles (either two dominant or two recessive); also called pure
Meiosis
I
Meiosis
II
xi. Heterozygous – have two different alleles; one dominant and one recessive; also called a hybrid
xii. Punnett Squares – used to held geneticists determine probable outcomes for offspring
b. Crosses – Mendelian
1. Monohybrid cross – a cross involving a single trait