More exam 2 studying

What is the first tenet of the modern cell theory?

All life is made up of one or more cells.

What is the second tenet of the modern cell theory?

All cells arise from pre-existing cells.

What is the third tenet of the modern cell theory?

Cells are the fundamental unit of structure and function in all life.

What is the fourth tenet of the modern cell theory?

The activity of an organism depends on the total activity of independent cells.

What is the fifth tenet of the modern cell theory?

Energy flow (metabolism) occurs within cells.

What is the sixth tenet of the modern cell theory?

Cells contain DNA.

What is the seventh tenet of the modern cell theory?

All cells are basically the same in chemical composition in organisms of related species.

What is the function of the plasma membrane?

Selectively permeable barrier, Communicating

What is the function of DNA in cells?

To code for proteins, reproduction

What occurs in the cytoplasm of cells?

Metabolism

What occurs in the ribosomes of cells?

Synthesis of proteins

What is the function of the cytoskeleton?

Structure, shape and support

What are the three protective layers found in prokaryotic cells?

Plasma membrane, Cell wall, Capsule

What is the function of flagella and/or cilia?

Movement

What is the function of pilus?

For Reproduction (conjugation)

What occurs in the nucleolus?

Ribosomes are assembled

What is chromatin?

Combination of DNA and the proteins that bind to it (histones)

What is the nuclear envelope?

Composed of 2 phospholipid bilayers; separates DNA transcription from translation

What is the function of nuclear pores?

Allows the passage of mRNA and other substances in & out of the nucleus

What do bound ribosomes do?

Attached to the rough endoplasmic reticulum, mainly produce proteins for export out of the cell (exocytosis) or in lysosomes

What do free ribosomes do?

Float freely in the cytosol; mainly produce proteins for use within the cell

What does the RER do to proteins?

Modifies the proteins by adding carbohydrates and phosphate groups

What does the SER do to lipids, cell membranes and steroids?

Synthesizes lipids, cell membranes, and steroids (cholesterol/testosterone/estrogen)

What does the Golgi apparatus do to proteins?

Concentrates, sorts, and packs proteins for secretion (transport)

What do peroxisomes do?

Accumulate toxic peroxides, the by product of some biochemical reactions, and break them down

What is the function of the mitochondria?

Take in energy rich molecules broken down in the cytosol (i.e. glucose) and makes ATP (adenosine triphosphate) by cellular respiration

What is the function of the chloroplasts?

Light energy is used to create carbohydrates by photosynthesis

What is the function of vacuoles?

Storage, structure, reproduction, and/or catabolism

What is the function of the cell wall?

Protects, maintains shape and prevents excess uptake of water

What is the function of the cytoskeleton?

Supports the cell and maintains shape, controls position and movement of organelles, moves the bulk of cytoplasm – cytoplasmic streaming, speeds up transport of molecules, helps anchor the cell and/or organelles in place by interacting with extracellular structures

What functions do the microfilaments perform?

Maintenance of cell shape, muscle contractions, cytoplasmic streaming, cell division (animals)

What functions do intermediate filaments perform?

Anchor nucleus and various organelles in place within the cell, maintenance of cell shape

What functions do microtubules perform?

Maintenance of cell shape, form a framework for motor proteins to move structures within a cell, aid in cell division (centrioles), form skeleton for projections out of the plasma membrane (i.e. flagella, cilia)

What functions do centrioles perform?

Produce the microtubules for cell and chromosome division when the cell divides (spindle fibers), Produce the basal body, which anchors cilia and flagella into the cell membrane

What functions does the extracellular matrix perform?

Holds cells together in tissues, contribute to physical properties of tissues, help orient cell movement in embryonic development

What are gap junctions?

Cytoplasmic channels that run between cells allowing substances to pass and allowing passage of materials through the ECM

What are desmosomes?

Link cells tightly with intermediate filaments, allowing substances to pass through the ECM

What are tight junctions?

Form a quilted seal not allowing movement of substances through the ECM

What are plasmodesmata?

Cytoplasmic channels that run between cells (cell walls and cell membranes) allowing substances to pass between cells

What are the components of the nucleus?

The components are the nuclear envelope, chromatin, nucleolus, and nucleoplasm.

Starting from the nucleus, what organelles (in the correct order) are involved in the endomembrane system?

Nucleus, Rough ER, Vesicle, Golgi apparatus, Vesicle, Plasma membrane

Which organelles are derived from prokaryotic organisms?

Mitochondria and Chloroplast

What cell component makes up the outer most layer of an animal cell?

Cell membrane

What is the cell membrane made out of?

Lipids and Proteins

What’s the liquid inside of a cell called?

Cytosol

What type of cell junctions allow materials to pass freely between adjacent cells?

Gap junctions

What is the cell membrane composed of?

Phospholipids and proteins

Is the cell membrane polar or non-polar?

Amphipathic molecules with polar and non-polar regions

How does cell signaling fuel the desperate flight of an impala sensing a cheetah?

The impala's brain signals the adrenal glands to release epinephrine into the blood, triggering a signaling cascade involving signal reception, transduction, and cellular response, ultimately leading to glycogen breakdown into glucose for muscle cell energy.

How do cells influence each other's behavior through communication?

Cells communicate to influence each other’s behavior, affecting gene expression, enzyme regulation, growth (mitosis), immune response, and nerve function.

What types of signals from the environment do living things need to process?

Light, heat, touch, and chemical signals (hormones). Cells respond to these using receptors.

How do cells communicate with one another through direct contact?

Gap junctions allow signal molecules to travel between cells, and surface proteins can interact between cells for communication.

How are signaling molecules secreted from the cell?

Signaling molecules (ligands) are translated in the rough endoplasmic reticulum, modified in the Golgi apparatus, packaged into vesicles, and secreted from the cell via exocytosis.

What are the different types of local and long distance regulators in cell signaling?

Paracrine (nearby cells), Hormone (distant cells via circulatory system), Synaptic (across synapse to next nerve cell), Autocrine (same cell that released them).

Why relay a signal to multiple components inside the cell to activate a cellular response?

Amplification

What are the steps of a signal transduction pathway?

Reception, Transduction, Amplification, Response

What are the different types of membrane bound receptors based on their function?

Ion-gated channels, G-Protein Coupled Receptors, and Receptor Tyrosine Kinases

What is a kinase?

A kinase is an enzyme (protein) that catalyzes (speeds up) the transfer of a phosphate group from one molecule to another.

How do ion channel receptors work?

Receptor is a protein embedded in the plasma membrane. Once a ligand binds to the receptor protein, the protein changes shape, opening its gates and allowing ions to flow through.

How do G Protein-Coupled Receptors work?

Ligand binds to receptor, causing it to change its shape. It now can bind an inactive G-protein, thus activating the G-protein. The G-protein leaves the receptor and goes on to activate other receptors in the cell.

How do Receptor Tyrosine Kinase (RTKs) work?

Ligand binds to 2 receptors, causing them to bind to one another. This dimerization activates the receptors, which then become phosphorylated at their tyrosine sites. The phosphorylated receptor can now bind to relay proteins, that themselves become activated and move on to activate other molecules

What kind of ligand binds to Cytoplasmic (intracellular) receptors?

small or nonpolar molecule that can pass through the membrane

What is the purpose of the signal transduction pathway?

Amplification

What are the 3 main ways a cell responds to the second messengers?

Opening of channel proteins, alterations in gene expression, alteration of enzyme activities

How do different cells respond differently to the same signal molecule?

Livers cells, heart cells, and lung cells all respond to epinephrine, but each cell type has its own unique proteins, so each cell type responds in a different way.

What is Apoptosis?

Apoptosis is programmed cell death (or suicide), which is controlled and highly regulated.

What is the difference between Apoptosis and Necrosis?

Apoptosis is programmed cell death, this happens when the cell is no longer needed or if the cell has lived long and is prone to genetic damage. Necrosis occurs when cells are damaged.

Does Apoptosis require signal to start process?

requires signal to start process

If a protein signal released by the thyroid gland had an effect on the liver, what kind of signaling would it be classified as?

Endocrine signaling

Which of the following types of signaling requires direct contact between cells?

Signaling between gap junctions

Glucocorticoid receptors bind to estrogen and testosterone, both small, nonpolar ligands. Which of these would be true regarding glucocorticoid receptors?

They are cytoplasmic receptors

What is the role of enzymes?

Speed up reactions (catalyze).

What is the defensive biological role of proteins?

Antibodies that recognize foreign substances.

What is the role of receptors in proteins?

To receive and respond to signals.

What is the storage role of proteins?

To store amino acids for later use.

Give an example of a structural protein.

Collagen.

Give an example of a transport protein.

Hemoglobin.

Which proteins are involved in movement?

Contraction and motor proteins.

What are the building blocks of proteins?

Amino acids.

How are amino acids grouped by their side chains?

Nonpolar, polar, and electrically charged.

Where do nonpolar side chains tend to be located within a protein?

Cluster together on the inside of the protein.

What type of bonds do polar side chains form?

Form hydrogen bonds.

What type of bonds do electrically charged side chains form?

Forms ionic bonds.

What are peptide linkages?

Covalent bonds that link amino acids together.

What is a polypeptide's primary structure?

Specific and unique sequence of amino acids linked covalently between N & C termini.

What type of bonds are involved in secondary structure?

Hydrogen bonds form between the amino and carboxyl groups of the amino acid building blocks forming α-helices and β-pleated sheets.

What bonds and interactions occur in tertiary structure?

Ionic / hydrogen bonds, hydrophilic/phobic interactions, van der Waals interactions, disulfide bridges.

What is quaternary structure?

Interactions of side chains of 2 or more different polypeptides bound together using all interactions/ bonds giving a fibrous or globular shape

What are chaperonins?

Protein molecules that assist in the proper folding of other polypeptides.

What happens when a polypeptide is denatured?

Breaks down the bonds and interactions that hold the secondary & tertiary structure together.

What are the biological uses of nucleic acids?

Storage, transmission, and use of genetic information.

What are the storage and transmission roles of nucleic acids?

DNA is a permanent storage place, and RNA transmits the genetic information from DNA to the protein synthesizers in the cell.

What is chromatin?

DNA wrapped around protein.

What are the building blocks of nucleic acids?

Nucleotides.

What are the three steps of genetic information transmission and use?

DNA Replication, Transcription, Translation.

What happens during DNA replication?

DNA makes identical copies of itself for every cell.

What happens during transcription?

DNA's genetic information is transmitted into an RNA copy.

What happens during translation?

RNA uses the genetic information transcribed from DNA to create a new protein (polypeptide).

What is the structure of nucleotides?

Monomers of nucleic acids made up of a nitrogenous base, a pentose sugar, and a phosphate group.

What are the nitrogenous bases in DNA and RNA?

Adenine (A), Guanine (G), Cytosine (C), and Thymine (T); in RNA, Thymine is replaced by Uracil (U).