Bio Exam 3 Flashcards
Function of nervous system
Receives + processes sensory information both external and internal environments
2 components of mammalian nervous system
Central Nervous System (CNS)- brain + spinal cord
Peripheral Nervous System (PNS) - nerves that transmit messages to CNS
Explain Neurons
Cells that transmit nerve impulses between nervous system
Neuroglia or Glial Cells
Accessory cell type to neurons that aid in their functions.
3 classes of Neurons
Sensory, Motor, and Interneurons
Explain sensory neurons
Take messages to CNS
Explain Motor neurons
Take messages from CNS to an organ, muscle fiber, or gland
Explain Interneurons
Receive info from sensory neurons and/or other interneurons in the CNS
3 main regions of a Neuron + explain
Cell body - contains nucleus
Dendrites - extensions that lead TOWARD cell body that receive signals from other neurons
Axon- conducts nerve impulse away from cell body AWAY from cell body towards cell body
Explain Myelin Sheath
Axonal protective covering
Formed by a glial cell type called Shwann Cells
What are the Nodes of Ranvier
Gaps where there are no Myelin Sheaths
Explain 1st phase of nerve impulse
Resting Potential (-70mV)
Inside of axon negative compared to outside
Explain 2nd phase of nerve impulse
Active/Action Potential Begins (-55 mV)
Rapid change in polarity across axon membrane as impulse occurs
Explain 3rd phase of nerve impulse
Depolarization (+35 mV)
Sodium channels open and Na+ moves inside axon
Explain 4th phase of nerve impulse
Depolarization (-70mV)
Action potential ends
Potassium gates open and K+ moves outside axon
Hyperpolarization can occur, where mV decreases further
As soon as an action potential moves on from region on axon, the previous axonal section goes under a _____
Refractory period
Explain refractory period
Sodium channels unable top open
Prevent backwards flow of action potential
Keep action potential moving forward
Saltatory Conduction
gated ion channels are concentrated on Nodes of Ranvier
Action potential travels faster on myelenated axon
2 ions required for action potential to occur
Sodium Na+ and Potassium K+
Explain Sodium Ion
Important for Depolarization
Flows into axon
+35mV
Explain Potassium Ion
Important for Depolarization
Flows out of Axon
Returns axon to resting potential, -70mV
Explain Synapse
-Every axon branches into many find endings, called an axon terminal
-Each axon terminal lies closely to dendrites or cell body of another nueron = SYNAPSE
-Separated by synaptic cleft
Explain neurotransmitters
Carries out communication between 2 neurons
Stored in synaptic vesicles in axon terminals
Releases Ca^2+ (Calcium Ion)
2 most common neurotransmitters
Acetylcholine (ACh) and Norepinephrine (NE)
DNA - genetic material of life must follow 2 rules:
Be able to store information that pertains to development, structure, and metabolic activities of a cell/organism, AND Stabilize this information so that it can be replicated with high accuracy during cell division and be transmitted from generation to generation
Who officially/unofficially discovered DNA
Official: James Watson + Francis Crick
Unofficial: Rosalind Franklin
Explain structure of DNA
Chain of nucleotides (ACTGs)
-Adenine, Cytosine, Thymine, Guanine
Antiparallel
Explain nucleotides complex
- Phosphate group
- Pentose sugar (deoxyribose)
- Nitrogenous base (ACTG)
Purines (double ringed): A, G
Pyrimidines (single ringed): T, C
Purines should always bond with ___
Pyrimidines
A:T (2 hydrogen bonds)
G:C (3 Hydrogen Bonds)
3 steps on DNA job in order
Replication (DNA - DNA)
Transcription (DNA - RNA)
Translation (RNA - Proteins)
What is DNA replication
The process of copying one DNA double helix into TWO identical double helices
Process is deemed semiconservative
The new double helix from this process has one conserved strand and one new strand
Explain specific Steps of DNA replication
1.DNA helicase “unzips” the double-stranded DNA (dsDNA) by breaking weak hydrogen bonds between the nucleotide bases.
2. DNA polymerase (DNAP) adds complementary DNA nucleotides. DNAP knows what nucleotide to add because it uses each original strand as a template for the new strand.
3. DNA ligase seals the pieces of DNA together.
3 parts of DNAP
- Leading strand – always 3’ to 5’ direction. Results in continuous formation of a NEW strand by DNAP.
- Lagging strand – always 5’ to
3’ direction. Results in discontinuous formation of a NEW strand by DNAP,
resulting in Okazaki fragments. - Okazaki fragments – short
segments of DNA
What is DNA transcription
A gene is a sequence of nucleotides that encodes for an RNA molecule.
RNA (ribonucleic acid) is a single stranded sequence of nucleotides.
A segment of DNA (gene) = template for an RNA molecule. The process of transcription is the exact same as DNA replication, except the enzyme is called RNA Polymerase
RNA polymerase - Same exact process as DNA replication. What’s the ONLY difference (aside from RNA polymerase)?
Whenever there is an Adenine present on original DNA molecule, a Uracil molecule is used for the mRNA molecule (instead of Thymine).
Explain Translation
Process by which an RNA sequence is read to make proteins
Occurs at the ribosome
Genetic code is triplet in nature = codon
4 mRNA bases/choices to choose from:
A, C, U, G
3 (triplet) bases = 1 protein (4x4x4) =
64 possibilities of making different
kinds of proteins
What do AUG and UGA/UAA/UAG mean?
AUG = Start Codon – tells the ribosome
when to start translation
UGA, UAA, UAG = Stop Codon – tells the
ribosome when to stop translation
Define immunity
Condition where body is protected from various threats, like pathogens toxins, and cancer cells
Explain Antigens
Any molecule that stimulates an immune response
Innate Immunity
Mechanisms in body that are fully functional w/o previous exposure to an antigen
Lots of White Blood Cells
“Police Force”
Adaptive Immunity
Initiated + amplified after specific recognition of Antigens - involves B and T cells
Comes into play if innate defense isn’t enough
“FBI”
Lymphoid Organs
Contain large numbers of Lymphocytes
Primary - red bow marrow + thymus (where lymphocytes develop+mature)
Secondary - lymph nodes + spleen (lymphocytes become active)
B vs T cells
B - Produce antibodies to attack foreign invaders
T - Direct fighters of foreign invaders + help to activate other parts of immune system
Examples of innate immunity physical+ chemical barriers
Physical - Skin, Mucous Membranes
Chemical - Secretion of oil glands, Acidic pH of stomach, native (good) bacteria
Explain inflammation
Complex mechanisms that prevent further infection and increase exposure /access of the immune system to area of concern (warmth, swelling, redness, pain)
Explain Antibodies
AKA immunoglobulins
Y-shaped molecules- Antigen binding sites
Made by B cells
Define Active Immunity
Individual alone produces immune response against an antigen
Ex.Vaccination
Virulent definition
Able to cause disease
Passive Immunity
Individual receives antibodies or cells from another individual
Ex. Breast Feeding
Define Taxonomy
Discipline of identifying and grouping organisms according to certain rules
Define systematics
Study of evolutionary relationships between 1 or more species
Define Taxa/taxon
Basic classification categories - domain kingdom phylum class order family genus species
Explain Domain
Bacteria, Archaea, Eukarya
Largest/most inclusive classification
Discovered by Carl Woese
4 kingdoms with Domain Eukarya
Protists, Fungi, Plantae, Animalia
Explain Protists
Can be single-celled OR multicellular
Some can photosynthesize, some need to get from environment
Explain Fungi
Helps decompose dead organisms (how they eat)
Explain Plantae
Multicellular
Photosynthetic
Explain Animalia
Multicellular
Must ingest + process food
Define homologous structure
Structures that are anatomically similar because they are inherited from a common ancestor
Analogous Structures
Structures that serve same function but not constructed similarly, nor share common ancestor
Almost all living organisms have the same basic biochemical molecules -
DNA, ATP, Identical/Similar enzymes
Ecology definition
Study of interactions organisms with each other + environment
Explain competitive exclusion principle
Idea that no two species can occupy the same ecological niche at the sane time if resources are limited
Explain resource partitioning
When there is a division of resources of feeding niches in an environment
Explain Coevolution
Process by which 2 species adapt overtime in response to each other
Symbiosis definition
Close interactions between 2+ living organisms
Parasitism definition
Parasite (benefits) derives nourishment from another organism (host, harmed)
Commensalism definition
One species benefits other one is neither harmed nor benefits
Mutualism definition
Both species benefit
Describe Conservation Biology
Interdisciplinary science w/ main goal of preserving + protecting biodiversity + Earth’s natural resources
Goal is to educate + take action
4 ethical principles of Conservation Biology
- Biodiversity is desirable for biosphere/humans
- Human-induced extinctions are undesirable
- Complex interactions with ecosystems support biodiversity + maintenance of these is desirable
- Biodiversity generated by evolutionary change had essential value
Endangered species definition
Faces immediate extinction thought all or most of its range (environments)
Threatened Species definition
Likely to become endangered in foreseeable future
3 levels of Biodiversity (Ascending Order)
Genetic, Ecosystem, Landscape
