- What are the basic concepts of the cell theory?
- Each cell maintains homeostasis
- Cells are the building blocks of all organisms
- All cells come from the division of preexisting cells
- Cells at the smallest units that carry out life’s essential physiological functions.
- What is the difference between sex cells and somatic cells?
- Sex cells - Are reproductive cells (sperm / ova)
- Somatic cells - All other cells in the body
- What are the four functions of the plasma membrane? List and briefly describe each one.
- Physical isolation - physical barrier that separates the inside of the cell
- Regulation of exchange with the environment - Controls entry of ions and nutrients, elimination of waste, and the release of secretions
- Sensitivity to the environment - First part of the cell affected by changes in composition, concentration, or pH of extracellular fluid
- Structural support - Gives tissue stability
- Give the functions of each of these components in the plasma membrane:
a. Membrane lipids
i. What role do the phospholipids play in the membrane?
ii. What role does cholesterol play in the membrane?
A. Physical barrier that separates the inside of the cell
B. Stiffens the plasma membrane making it less fluid and less permeable
- Give the functions of each of these components in the plasma membrane:
Membrane proteins – list and briefly describe the 6 types.
- Anchoring proteins - Attach the plasma membrane to other structures and stabilize its position.
- Recognition proteins - Immune system cells - recognize other cells as normal or abnormal
- Enzymes - Catalyze reactions in the extracellular fluid or in the cytosol
- Receptor proteins - Sensitive to ligands - binding trigger changes in the activity of the cell
- Carrier proteins - Bind solutes and transport them across the plasma membrane
- Channels - Central pore - forms a passageway completely through the plasma membrane
- Give the functions of each of these components in the plasma membrane:
Membrane carbohydrates – list and briefly describe the 4 functions of the glycocalyx.
- Lubrication and protection - Forms a viscous layer that lubricates and protects the plasma membrane
- Anchoring and locomaotion - Help anchor the cell in place. Movement of specialized cells
- Specificity in binding
- Recognition - Cells involved with immune response glycoproteins and glycolipids as normal or abnormal
- What is the definition of cytoplasm?
A general term for the material between the plasma membrane and the membrane that surrounds the nucleus
- What are the differences between the cytosol and the extracellular fluid?
- Sodium and potassium concentrations differ - potassium higher in cytosol - sodium higher in extracellular
- Suspended protein concentrations differ - Cytosol contains more
- Nutrient concentrations differ - cytosol usually is small
- Give the functions of the following non-membranous organelles:
Cytoskeleton
Gives the cytosol strength and flexibility
Support for organelles
Keep them in their proper position
Give the functions of the following non-membranous organelles:
Microfilaments
Anchor the cytoskeleton
Determine the consistency of the cytosol (interacting with other proteins)
Give the functions of the following non-membranous organelles:
Microtubules
Forms the main portion of the cytoskeleton
Change the shape of the cell
Assist in cell movement
More vesicles / organelles within the cell
Give the functions of the following non-membranous organelles:
Microvilli
Increase surface area to facilitate absorption of extracellular materials
Give the functions of the following non-membranous organelles:
Centrioles
Essential for movement of chromosomes during cell division
Organization of microtubles in cytoskeleton
Give the functions of the following non-membranous organelles:
Cilia
A primary cilium acts as a sensor
Motile cillia more materials sperm
Give the functions of the following non-membranous organelles:
Flagella
Movement of the cell
Only human cell with flagellum is sperm
Give the functions of the following non-membranous organelles:
Ribosome
Protein synthesis
- There are two types of endoplasmic reticulum: smooth and rough. Give the functions of each one
- Smooth
a. Synthesis of the phospholipids and cholesterol
b. synthesis of steroid hormones
c. synthesis and storage of glycerides
d. synthesis and storage of glycogen - Rough
a. Fixed Ribosome synthesize proteins
b. Chemically modified in the RER and packaged for export to the Golgi Apparatus
- List the 4 functions of the Golgi apparatus.
- Modifies and packages secretions (hormones and enzymes)
- Adds or removes carbohydrates to or from proteins
- Renews or modifies the plasma membrane
- Packages special enzymes within vesicles (lysosomes)
- What is the function of the lysosome?
Intracellular removal of damaged organelles or pathogens
- What is the function of the peroxisomes?
Catabolism of fats and other organic compounds
Neutralization of toxic compounds generated in the process.
- What is the function of the mitochondria?
Produces 95% of the ATP required by the cell
- Give the function of the following components of the nucleus:
nuclear envelope
Separates the nucleus from the cytosol
Give the function of the following components of the nucleus:
Nuclear pore
Chemical communication between the nucleus and cytoplasm
Regulates transport of materials
Give the function of the following components of the nucleus:
Nucleoli
rRNA synthesis and assembly of ribosomal subunits
- The nucleus contains DNA. What is the function of the DNA?
Stores instructions for protein synthesis
- What is the difference between chromatin and chromosomes?
Chromatin - nucleosomes are loosely coiled, forming a tangle of filaments
Chromosomes - chromatin coils tighter, becoming chromosomes (during cell division)
The _______________________ ________________ is the chemical language the cell uses to make proteins in the human body. The information is stored in a sequence of base nucleotides. The nitrogenous bases for DNA include _______________, __________________, ___________________, and ________________________. Base nucleotides are read 3 at a time as a triplet. Each triplet represents one __________________ ________________. A ____________ is the functional unit of heredity and contains enough nucleotides to code for a protein.
Genetic code
adenine
thymine
cytosine
guanine
Amino acid
gene
- Each gene that is to be read has a “start” region called the _________________ and each gene ends with a ___________ signal.
Promoter
Stop
- Define transcription. In what location of the cell does this process take place?
Synthesis of RNA from a DNA template
Nucleus
- What is the functional role of RNA polymerase during transcription?
Promotes hydrogen bonding
Begins as a start signal
- Protein synthesis depends on the Law of Complimentary Base Pairing which states that the base Cytosine always combines with Guanine and Thymine always combines with Adenine in DNA and Uracil in RNA. Given the strand of DNA below, give the strand of RNA that would be produced from that DNA sequence.
T A C G G C A C T G C A
AUGCCGUGACGU
- A series of three base nucleotides on the coding strand of DNA is called a triplet. The complementary series of three base nucleotides on the mRNA strand is called a ____________. The complementary series of three base nucleotides on a tRNA is called an _________________.
Codon
Anticodon
- Define translation. In what location of the cell does this process take place?
Formation of a linear chain of amino acids, a polypeptide, using the information from a mRNA strand
Cytoplasm
List the three major phases in translation. Briefly describe each phase.
- Initiation - Begins as the mRNA strand binds to a small ribosomal subunit as the start codon. The attachment of tRNA and the subsequent binding of the large ribosomal subunit creates a functional ribosome, with the mRNA nestled in the gap between the small and the large ribosomal subunits.
- Elongation - Amino acids are added to the growing polypeptide chain. As the ribosome moves along the mRNA strand. Translation proceeds swiftly, produces a protein in 20 seconds.
- Termination - Elongation ends when the ribosome reaches the stop codon at the end of the mRNA strand. The mRNA stays intact and can interact with other ribosomes to create additional copies of the same polypeptide chain.
- Clinical Note: What is a mutation? What are some examples of point mutations?
Permanent changes in the cells DNA that affects the nucleotide sequence of one or more genes.
Certain cancers, thalassemia, and sickle cell amina
- Turn to page A-4 in the appendix of your textbook. This is a chart that gives the amino acids coded for on the mRNA codons. Given the template strand of DNA below, provide the base nucleotide sequences for the following:
T A C A A A C G G T G T A C T
a. Coding strand of DNA:
b. mRNA formed:
c. Anticodons of tRNA:
d. Amino acid sequence: Don’t need to remember
A. ATGTTTGCCACATGA
B. UACAAACGGUGUACU
C. AUGUUUGCCACAUGA
D. Start, Phenylalaninel, Alanine, Threoninel, Stop