Mod 1 Flashcards
What is biochemistry?
The chemistry of life.
What are the practical applications of biochemistry in biomedical sciences?
- Disease
- Drug discovery
- Therapeutics
What elements were present in the primordial universe?
- Hydrogen
- Helium
What are the primary elements that make up the human body?
- Hydrogen (60%)
- Oxygen
- Carbon
What elements are found in the Earth’s crust that are not in the human body?
- Silicon
- Aluminum
What is the role of oxygen in biochemistry?
Building block of biomolecules and water.
What is the role of carbon in biochemistry?
Building block of all organic molecules.
What is the role of hydrogen in biochemistry?
Component of water, biomolecules, main component of pH in body fluids.
What is the role of nitrogen in biochemistry?
Component of protein and nucleic acids (biomolecules).
What is the role of phosphorus in biochemistry?
Component of biomolecules (nucleic acids).
What is the role of sulfur in biochemistry?
Component of biomolecules (proteins).
Define ‘element’ in the context of biochemistry.
A basic substance that cannot be broken down into anything more basic.
What is a macromolecule?
A polymer of monomeric building blocks.
What type of reaction leads to the formation of macromolecules/polymers?
Condensation reaction.
Name the three essential biological macromolecules.
- Nucleic acids (DNA and RNA)
- Proteins
- Carbohydrates
What are the components of nucleic acids?
both RNA and DNA
- A sugar
- 5’ phosphate group
- 1’ nitrogenous base (ACGT for DNA, ACGU for RNA)
How do DNA and RNA differ in structure?
DNA is double stranded; RNA is single stranded
2’ H (DNA)
2’ OH (RNA)
What are proteins made of?
Amino acids.
What is the backbone structure of amino acids?
Amino (N) + Carboxyl (C) group
with a variable R group
Carbohydrates vs complex carbs
Carbohydrates:
Made of saccharides
Complex carbs:
made of many monomers (ex. cellulose)
What is a monosaccharide?
One sugar ring structure (e.g., glucose).
What is a disaccharide?
Composed of two types of sugars bound covalently.
What is meant by condensation linkage in carbohydrates?
Joining two sugars removes a water molecule.
A cell is living bc it is …
isolated (by a membrane)
What is the function of the cell membrane?
- Selective permeability
- Control molecular traffic
- Compartmentalization
- Cell-to-cell communication
Describe the lipid bilayer.
Semi-permeable structure made of amphipathic membrane lipids.
What role do proteins play in the cell?
- Speed up chemical reactions (enzymes)
- Maintain cell structure
- Aid in cell division
What role do carbs play in the cell?
- Broken down to make energy
- Help maintain cell structure
What are pili in bacteria?
Structures that allow bacteria to attach to surfaces and other cells.
What are flagella in bacteria?
Structures that allow bacteria to swim through aq environments
What is the peptidoglycan layer in bacterial cells?
A combination of amino acids and sugars that provides structure, protection, and rigidity.
What distinguishes Gram-positive from Gram-negative bacteria?
Gram-positive has a thicker peptidoglycan layer
- deep purple
Gram-negative has an outer membrane, so 2 membranes
- pink/red
What is the difference between cytosol and cytoplasm?
Cytosol is the liquid, while cytoplasm includes cytosol and all suspended structures.
What is the endomembrane system?
Includes nuclear envelope, lysosomes, vesicles, ER, Golgi, and plasma membrane.
True or False: Eukaryotic cells have organelles, prokaryotic bacteria don’t
True.
Fill in the blank: The __________ is the area where bacteria store DNA.
nucleoid
What are supramolecular complexes held together by?
Weaker, non-covalent bonds.
What are monomeric subunits held together by?
Very strong covalent bonds
What is the endomembrane system?
Grouping of membranes and organelles that function together to modify/package/transport molecules
Includes nuclear envelope, lysosomes, vesicles, ER, Golgi, and plasma membrane
What is the plasma membrane made of?
Phospholipid bilayer with 2 fatty acid chains, glycerol backbone, and phosphate group
The plasma membrane also contains embedded proteins, cholesterol, and carbohydrates.
What is the function of microvilli and what is it?
Fingerlike projections of folded plasma membranes of cells
Increase surface area for absorption
They are found lining the small intestine and specialize in absorbing nutrients from digested food.
What is cytoplasm?
All cell contents between the plasma membrane and the nuclear envelope
It is made of organelles suspended in cytosol and has a 70-80% water composition.
What is the function of the cytoskeleton?
Maintains cell shape, secures organelles, allows movement within the cell, and enables unicellular movement
It is a network of protein fibers.
What are the three types of fibers in the cytoskeleton?
- Microfilaments (actin)
- Intermediate filaments
- Microtubules
Each type has distinct functions related to cell structure and movement.
What is the function of the centrosome?
Microtubule organizing center in animal cells
It contains a pair of centrioles and replicates before cell division.
What distinguishes flagella from cilia?
Flagella are long and used to move entire cells - only one or a few
Cilia are short and can move cells or substances - many present
What is the nucleus?
Most prominent organelle in a cell that houses DNA in the form of chromatin
It directs the synthesis of ribosomes and proteins.
What is the nuclear envelope?
Double-membrane structure containing pores.
What are chromosomes?
Structures within the nucleus made up of DNA and protein
They are only visible when the cell is about to divide.
What is the function of the rough endoplasmic reticulum (RER)?
Modifies proteins and makes phospholipids
It has ribosomes on its surface, giving it a studded appearance.
What does the smooth endoplasmic reticulum (SER) synthesize?
- Carbohydrates
- Lipids
- Steroid hormones
It also detoxifies medications and poisons and stores calcium ions.
RER vs SER ribosomes
RER
- Named this bc ribosomes give studded appearance
SER
- Few or no ribosomes
What is the function of the Golgi apparatus?
Sorts, tags, packages, and distributes lipids and proteins.
What are lysosomes?
Cell’s garbage disposal that digests and recycles materials using enzymes at low pH
They are active at low/acidic pH.
What is the role of ribosomes?
Responsible for protein synthesis
They are clusters or tiny dots in the cytoplasm.
What is the function of mitochondria?
Make ATP by glucose breakdown through cellular respiration.
What do vesicles and vacuoles do?
storage and transport
Enzymes within plant vacuoles can break down macromolecules
What do peroxisomes do?
Perform oxidation reactions that break down fatty acids and detoxify poisons
They produce hydrogen peroxide H2O2 as a byproduct.
What is the fluid mosaic model?
Describes the plasma membrane as a mosaic of components that can flow and change composition while maintaining membrane integrity
Developed by Singer & Nicolson in 1972.
What are the main components of a plasma membrane?
- Phospholipid molecules
- Proteins
- Carbohydrates
- Cholesterol
cholesterol only in animal cells
Phospholipid molecules in membrane
most abundant
- Hydrophilic on inside and outside, polar, in contact with aqueous
- Hydrophobic interior, nonpolar, fatty acid tails
Proteins in membrane
second most abundant
embedded/integral or peripheral
Carbs in membrane
- Always found on exterior surface
- Bound either to proteins (forming glycoproteins) or to lipids (forming glycolipids)
Cholesterol in membrane
- Regulates the fluidity of the membrane based on the temperature of the cell’s environment
- More abundant in animals that live in cold climates
How do viruses infect specific organs?
By exploiting glycoproteins on the surface of cell membranes.
Virus coat molecules mimic so antibodies aren’t made
Eukaryotes vs prokaryotes
Eukaryotic
- Animal cells
- Plant cells
- Fungal cells
- Protist cells
Prokaryotic
- Bacteria
- Archaea
What is cell theory?
All living things are composed of one or more cells; the cell is the basic unit of life
Developed by Matthias Schleiden and Theodor Schwann in the late 1830s.
What distinguishes eukaryotic cells from prokaryotic cells?
Eukaryotic cells have a nucleus and organelles; prokaryotic cells do not.
What is a micrograph?
An image of cells taken with a microscope.
Light microscopy
- Uses magnification (degree of enlargement) and resolving power (ability of a microscope to allow the eye to distinguish two adjacent structures as separate)
- High resolution = objects can be closer and better clarity and detail
- Thin or translucent sample
- Binocular
Dissecting microscope
20 to 80x magnification
- Can provide a 3D view of the specimen
- Can look at thick objects and many components in focus at the same time (anatomy of whole organism)
- Binocular
What is the difference between scanning and transmission electron microscopes?
- Scanning electron microscope: provides 3D views of cell surfaces
- Transmission electron microscope: transmits an electron beam through a specimen to view internal structures.
What is the difference between light and electron microscopes?
Electron more bulky and expensive than light microscopes
work best in a vacuum
What did Robert Hooke contribute to cell biology?
Coined the term ‘cell’ in 1655.
What did Antony van Leeuwenhoek observe?
Movement of protists and sperm, which he called ‘animalcules’
Discovered bacteria and protazoa
