Genetics Unit 1

26' Bagwell

hierarchy of Living Things

The organization of biological entities in levels, starting from cells, tissues, organs, and systems, up to organisms, populations, communities, ecosystems, and the biosphere.

Sexual vs Asexual reproduction. Give pros and cons of each and which organisms carry out each.

Sexual reproduction involves the fusion of gametes from two parents, leading to genetic variation, while asexual reproduction involves a single organism replicating itself, leading to genetically identical offspring. Pros of sexual reproduction include increased genetic diversity; cons include the need for two parents. Asexual reproduction is quicker and requires less energy, but lacks genetic variation. Organisms like animals and plants primarily reproduce sexually, whereas bacteria and some plants reproduce asexually.

Cell differentiation or specialization. How does it happen?

is the process by which a less specialized cell becomes a more specialized cell type, allowing for the formation of different tissues and organs in an organism. This process occurs through gene expression regulation, where certain genes are turned on or off, influencing the cell's development into specific types like muscle, nerve, or blood cells.

Polar molecule

A molecule with a net dipole moment due to the presence of polar bonds, resulting in an uneven distribution of electron density.

nonpolar molecule

A molecule that does not have a net dipole moment, resulting from an even distribution of electron density and typically consisting of nonpolar covalent bonds.

intermolecular forces

Forces occur between molecules, affecting physical properties such as boiling and melting points. They include hydrogen bonds, dipole-dipole interactions, and London dispersion forces. It occurs outside the molecule.

intramolecular forces

are forces that occur within a molecule, holding the atoms together through covalent or ionic bonds. These forces determine the structure and stability of the molecule.

4 macromolecules and their monomers

Carbohydrates

Monomer: Monosaccharides (e.g., glucose)

Lipids

Components: Glycerol and fatty acids (Note: Lipids do not form traditional polymers like the others but are grouped here)

Proteins

Monomer: Amino acids

Nucleic Acids

Monomer: Nucleotides

Function of Proteins

Does most things in cell (structural support, enzymes, immune defense)

Functions of Lipids

long-term energy, insulation, part of cell membrane

Function of nucleic acids

Store and transmit genetic information (DNA and RNA)

functions of carbs

short-term energy and structural support of organisms

7 functional groups

• Hydroxyl (–OH)

  • Properties: Polar, forms hydrogen bonds, increases solubility in water

  • Effect on molecules: Makes molecules more hydrophilic

  • Example: Alcohols (ethanol), sugars

• Carbonyl (C=O)

  • Properties: Polar, reactive

  • Effect on molecules: Helps distinguish ketones (internal carbonyl) from aldehydes (end carbonyl); important in energy storage molecules

  • Example: Glucose, acetone

• Carboxyl (–COOH)

  • Properties: Acidic; can donate an H⁺ ion

  • Effect on molecules: Acts as an acid, often negatively charged in cells

  • Example: Amino acids, fatty acids

• Amino (–NH₂)

  • Properties: Basic; can accept an H⁺ ion

  • Effect on molecules: Acts as a base, often positively charged in cells

  • Example: Amino acids, proteins

• Sulfhydryl (–SH)

  • Properties: Slightly polar; can form disulfide bonds

  • Effect on molecules: Helps stabilize protein structure

  • Example: Some amino acids (cysteine)

• Phosphate (–PO₄²⁻)

  • Properties: Negatively charged, polar

  • Effect on molecules: Involved in energy transfer and signaling; increases solubility

  • Example: ATP, DNA, RNA

• Methyl (–CH₃)

  • Properties: Nonpolar, hydrophobic

  • Effect on molecules: Affects gene expression, molecular shape, and reactivity

  • Example: DNA methylation, fats

What is the basic structure of an amino acid? What are the 4 categories of amino acids and what gives them this property?

An amino acid has a basic structure consisting of a central carbon atom bonded to an amino group, a carboxyl group, a hydrogen atom, and a variable R group. The R group determines the chemical properties of the amino acid and how it behaves in proteins. Amino acids are grouped into four main categories based on their R groups: nonpolar amino acids, which have hydrophobic R groups made mostly of carbon and hydrogen; polar amino acids, which have hydrophilic R groups that can form hydrogen bonds with water; electrically charged amino acids, whose R groups are acidic or basic and carry a positive or negative charge; and special-case amino acids, which have unique R groups that give them distinctive properties such as forming disulfide bonds, increased flexibility, or causing bends in protein chains.

4 structures of a protein

Primary structure is the linear sequence of amino acids in a protein and is held together by peptide bonds between amino acids. Secondary structure refers to local folding patterns such as alpha helices and beta pleated sheets, which are stabilized by hydrogen bonds between the backbone atoms of the polypeptide chain. Tertiary structure is the overall three-dimensional shape of a single polypeptide and is maintained by interactions among R groups, including hydrogen bonds, ionic bonds, hydrophobic interactions, and disulfide bridges. Quaternary structure occurs when two or more polypeptide chains combine to form a functional protein and is stabilized by the same types of interactions as tertiary structure, including hydrogen bonds, ionic bonds, hydrophobic interactions, and disulfide bonds.

What determines the function of a protein?  Trace this back as far as you can.

Ultimately, the function of a protein can be traced back to the DNA sequence of the gene that codes for it.

What is protein denaturing and why is it a bad thing? What things can cause a protein to denature?

Protein denaturing is the process in which a protein loses its normal three-dimensional shape due to the disruption of the bonds and interactions that hold it together. This is a bad thing because a protein’s function depends on its shape, and when the shape changes, the protein can no longer perform its specific job, such as catalyzing reactions or binding to other molecules. Proteins can be denatured by high temperatures, extreme pH levels, changes in salt concentration, and certain chemicals or heavy metals

What structure of a protein is unaffected by denaturing?

The nucletide sequence

What part of the amino acid/polypeptide participate in the bonds that hold together secondary structure? Tertiary structure?

In secondary structure, the bonds that hold the structure together involve the backbone of the polypeptide, specifically the amino and carboxyl groups of the peptide bonds, which form hydrogen bonds with each other to create alpha helices and beta pleated sheets. In tertiary structure, the bonds and interactions involve the R groups (side chains) of the amino acids, including hydrogen bonds, ionic bonds, hydrophobic interactions, and disulfide bridges, which together determine the protein’s overall three-dimensional shape.

How can a DNA mutation affect the function of a protein?

A DNA mutation can affect the function of a protein by changing the nucleotide sequence of a gene, which can alter the amino acid sequence during translation.

Enzyme

a biological catalyst, usually a protein, that speeds up chemical reactions in living cells without being consumed. It works by binding to a specific substrate at its active site, forming an enzyme–substrate complex. The enzyme lowers the activation energy of the reaction by correctly orienting the substrate, stressing or breaking chemical bonds, and creating a favorable microenvironment for the reaction to occur. Once the reaction is complete, the products are released, and the enzyme remains unchanged and able to catalyze another reaction.

Lactose is a sugar broken down by lactase into glucose and sucrose. What is the substrate and the enzyme in this reaction?

The enzyme is lactase and the substrate is lactose.

Protease is a digestive enzyme that breaks down protein, but does nothing to carbohydrates.  Why does protease have no effect on carbs?

because enzymes are highly specific to their substrates. The active site is shaped to bind to proteins and peptide bonds, not the glycosidic bonds found in carbs.

How does a gene mutation change how an enzyme will function?

can change the amino acid sequence of an enzyme, which may alter how the enzyme folds and change the shape of its active site.

How can a pH change effect an enzymes function

can disrupt hydrogen bonds and ionic bonds that maintain the enzyme’s shape. This can alter the active site or denature the enzyme, decreasing its ability to bind to the substrate and catalyze the reaction.

How can a noncompetitive inhibitor effect an enzymes function

binds to a site on the enzyme other than the active site, causing the enzyme to change shape. This reduces enzyme activity because the active site is altered, and increasing substrate concentration will not overcome the inhibition.

How can a competitive inhibitor effect an enzymes function

resembles the substrate and competes for binding at the active site. This reduces enzyme activity by blocking the substrate, but the effect can be reduced by increasing the substrate concentration.

How can temperature cause an enzymes function to change

enzyme activity increases due to faster molecular movement, up to an optimal temperature. Beyond this point, high temperatures can denature the enzyme, causing it to lose its shape and function, while low temperatures slow enzyme activity by reducing molecular motion.

Nucleus

Stores DNA and controls cell activities by directing protein synthesis and regulating gene expression.

Mitochondria

Carry out cell respiration and produce ATP

Chloroplast

Perform photosynthesis, convert light energy into chemical energy stored in glucose in plant cells

Smooth ER

Synthesizes lipids, detoxifies harmful substances, and stores calcium ions.

Rough ER

Transports proteins that will be used in membranes

Golgi apparatus

Modifies and packages proteins and lipids for transport. Cis face receives vesicles from the ER, but the Trans face ships finished products to their final destination.

Microtubules

Part of the cytoskeleton and help maintain cell shape, move organelles, and separate chromosomes during cell division

Vacuole

Stores water and wastes in plant cells to help it keep its cell shape.

Ribosomes

Synthesize proteins

Lysosomes

Contain digestive enzymes that break down macromolecules

Peroxisomes

Break down fatty acids and detoxify harmful substances with oxygen

Cell Wall

Provides support and protection to cell shape in plant cells only

Cell membrane

Selectively permeable barrier that chooses what enters and leaves the cell

Phospholipid bilayer

Basic structure of cell membrane, hydrophilic heads outward and hydrophobic tails inward, which creates a barrier to most polar substances2

Peripheral proteins

Proteins that are loosely attached to the cell membrane

Integral proteins

Proteins that are embedded within the membrane

Sterol

AKA cholesterol which helps maintain membrane fluidity by preventing the membrane from becoming too rigid or fluid

Glycoproteins

Proteins with carb chains that function in cell recognition, communication, and adhesion

Cell

Smallest unit of live that can carry out all vital functions

Abiogenesis

Idea that non living things create living organisms. Francesco Redi disproved this by showing that maggots only appear on meat when flies are able to lay eggs on it. Lazzaro Spallanzani further demonstrated that microorganisms come from other microorganisms by boiling broth and sealing it to prevent microbial growth. Louis Pasteur definitively disproved abiogenesis using his swan-neck flask experiment, showing that microbes come from the air and do not spontaneously generate.

Pancreatic cells secrete insulin, which is a protein. What organelles would be in their cell.

Abundant Rough ER, ribosomes, Golgi apparatus, and vesicles. Mitochondria would also be present for protein synthesis

Prokaryotic vs eukaryotic cells

Prokaryotic cells lack a nucleus and membrane-bound organelles and are generally smaller and simpler, while eukaryotic cells have a nucleus and membrane-bound organelles and are larger and more complex. Both types of cells contain DNA, ribosomes, and a cell membrane.

How are chloroplasts and mitochondria similar in the cell?

Both use glucose to create energy. The first through photosynthesis and the second through cell respiration

How are chloroplast, mitochondria, and the nucleus different from all the other organelles.

They all include DNA and are surrounded by a double membrane

Plant vs animal cells

P-include cell wall, chloroplasts, and central vacuole

A-have more centrioles and lysosomes

Semi-permeable

Membrane allows some substance to pass through but others can’t

How is amylase synthesized and secreted?

It is synthesized by ribosomes attached to the rough endoplasmic reticulum, where it enters the ER for folding and modification. It is then transported in vesicles to the Golgi apparatus, where it is further modified and packaged before being sent in secretory vesicles to the cell membrane and released by exocytosis.

How is the synthesis of chaperonins different from amylase?

They are synthesized by free-floating ribosomes in the cytoplasm and remain inside the cell, rather than being processed by the rough ER and Golgi apparatus for secretion.

Microbiome

community of microorganisms, including bacteria, fungi, and viruses, that live in and on an organism and play important roles in digestion, immunity, and overall health.