Lecture Notes exam 2 Flashcards
Sexual Reproduction
offspring arise from two parents and a mixture of genes are inherited from both, offsprings will have better chance of survival of effects of mutations
Asexual Reproduction
produces genetically identical copies of a single parent (clones)
Mitosis
somatic cells, purpose of growth, repair and replace, diploid to diploid
Meiosis
division of specialized cells that form reproductive cells known as gametes. A diploid cell into 4 haploid gametes. Nuclear division, halves chromosome number
2 Haploid Gametes fuse to produce
zygote
Zygotes are
diploid 2n
Gametes do not__, they ___
divide, produced by germ cells by meiosis
How many chromosomes in human somatic cell and how many pairs
46;23
Mitosis ___ chromosome number. Meiosis ___ chromosome number
maintain; reduce.
Haploid
single set of chromosome (n)
Diploid
double set of Chromosome (2n)
Genes
regions in an oragnism’s DNA that encode information about heritable traits. Pairs on homologous chromosomes.
Alleles
Different versions of the same gene.
DNA is replicated
Once
Meiosis 1
Diploid germ cell replicated its chromosome and form tetrad (pairs of duplicated homologous chromosomes); each duplicated homologous chromosome is separated from its partner
Meiosis II
two haploid cells cells divide, sister chromatids are separated (like in mitosis)
Stages of Meiosis I
Prophase: homologous chromosomes condense, pair up, and swap segments. Aka crossover stage
Metaphase: Chromosomes line up
Anaphase: Chromosomes separate
Telophase: A new nuclear envelope cause so two haploid nuclei form.
Stages of Meiosis II
Prophase II: the chromosomes condenses with no dna replication
Metaphase II: chromosomes align
Anaphase II: Sister chromatids separate
Telophase II: 4 haploid cells
Crossover
happens in proffer I, helps with genetic variability. mixture of both parents.
random assortment produces
2^23 possible combinations of homologous chromosome
Sporophytes
Diploid bodies with specialized structures that form spores (haploid cells) that give rise to gametophytes through mitosis
Gametophytes
A multi-celled haploid body inside which on ore more gametes form
fertilization
fusion of two haploid gametes (sperm and egg) resulting in a diploid zygote
Genes occur in pairs of
homologous chromosomes
Gregor Mendel
Breeding garden pea plants
Characters
heritable features that vary among individuals
Traits
variants for a character
Genes
Discrete heritable units of information for traits
Alleles
Alternative forms of a gene
Each gene has a specific ___on a chromosome
locus
How many chromosomes do diploid cells have
2 pairs of homologous chromosomes
Genotype
Particular set of allies that an individual carries
Bb, BB, bb
Homozygous
Two identical alleles of a gene is homozygous for that gene
Heterozygous
An individual with non-identical alleles of a gene
Phenotype
Observable traits such as color
Mutated genes are
new alleles whether or not it affects a phenotype
True breeding
individual that is homozygous for a particular trait; the same trait is produced over many generations. AA or aa
Hybrid
the heterozygote offspring of a cross between two individuals that breed true for different forms of a trait. Aa
Dominant and Recessive Alleles
Dominant is shown in a heterozygote phenotype and recessive is not
Genotypes of :
Homozygous dominant
Heterozygous
Homozygous recessive
AA; Aa; aa and they only have 2 phenotypes
Probability
A measure of the chance that a particular outcome will occur
Punnett square
a grid used to calculate the probability of genotypes and phenotypes among offspring of various crosses
Testcross
method of determine if an individual is heterozygous or homozygous dominant (BB x bb)
Monohybrid Cross
between two individuals that are heterozygous for a certain character. crossing of two true-breeding individuals resulting in heterozygote offspring and they are hybrids which are represented in the first filial generation. Then those hybrids are crossed with each other to produce the second filial generation
Mendel’s Law of Segregation
Differing traits in organisms result from pairs of genetic factors that separate during gamete formation such that each gamete receives only one of the two factors.
Dihybrid
16 results of genotypes, and phenotype ratio is 9:3:3:1
Mendel’s Law of Independent Assortment
during gamete formation, members of one pair of ‘genetic factors’ are distributed into gametes independently of other pair
Law of Segregation Modern
Different traits are the result of the separation of pairs of alleles on homologous chromosomes into discrete gametes during meiosis
Law of Independent Assortment Modern
Each pair of alleles is sorted into gametes independently of other pairs during meiosis; we now know that this law applies when the genes are located on different pairs of homologous chromosomes
Linkage group
all genes on one chromosome
genes are passed on together
Linked genes
very close together; crossing over rarely occurs between them
Codominance
two non-identical alleles of a gene are both fully expressed in heterozygotes, so neither is dominant or recessive
Multiple Allele System
genes with three or more alleles in a population
ex. blood types
Incomplete Dominance
one allele is not fully dominant over its partner, and the heterozygous offspring is a mix
Epistasis
Two or more gene products influence a trait, one gene product suppresses the effect of another (dog color)
Bell Curve
When continuous phenotypes are divided into categories and plotted as a bar chart.
genotype + environment=
phenotype
Are phenotypes qualitative
yes
Mendelian Genetics
Characters are controlled by a single gene
Alleles exhibit a complete dominance relationship
Phenotypes are qualitative
Pleiotropy
Single gene affecting many traits
Epigenetics
heritable changes NOT caused by change in DNA sequence
Genetic abnormalities
rare version of trait, not life-threateneing
Genetic disorder
does cause health problems, may be life threatening
Geneticists
study inheritance pattern in humans by tracking these genetic abnormalities and disorders through families
Pedigree
used to determine the probability that future offspring will be affected by a genetic abnormality or disorder
An allele is inherited in an autosomal dominant pattern if
if the trait it specifies appears in people with homozygous dominant and heterozygous genotypes
An allele is inherited in an autosomal recessive pattern if
if the trait it specifies appears only in people with homozygous recessive genotypes
Achondroplasia
Homozygous dominant individuals do not survive long enough to reproduce
Huntington’s Disease
Symptoms often do not develop until after 30 years of age
An affected individual may have already passed on the allele to offspring
Hutchinson-Gilford Progeria
Most individuals with this disease do not survive long enough to reproduce
Autosomal Recessive Inheritance
Skips generations, two recessive alleles, so heterozygotes do not have trait.
Albinism
Depending on which gene(s) are affected, absence or low levels of melanin may affect pigmentation of skin, hair, eyes
Autosomes and Sex Chromosomes pairs
22 pairs of autosomes(homologous) and 1 pair of sex chromosomes (non-homologs)
X-linked Disorders
inherit in a recessive pattern because dominant X chromosomes tend to be lethal in male embryos, only homozygous females have this disorder.
an ex. is color blindness
all new alleles arise by
mutation
duplication
DNA sequence that are repeated two or more times, duplication may be caused by unequal crossover in prophase
Deletion
Loss of some portion of a chromosome, usually causes serious or lethal disorders
Inversion
Part of the sequence of DNA becomes oriented in the reverse direction with no molecular loss
Translocation
If chromosome breaks, the broken part may get attached to a different chromosome, or to a different part of the same one.
Polyploid
they have three or more complete sets of chromosomes
Trisomy 21
down syndrome
Karyotype
arrangement of chromosome in pairs 23
Changes in sex chromosome number may
impair learning or motor skills or be undetected
Stem Cells
divide to produce more stem cells
OR
differentiate into specialized cells
Totipotent
embryonic stem cells develop into a individual
Embryonic Stem Cells (hESCs)
hold the potential to repair tissues that are normally not regenerated in the adult body
Cell Junctions
Connects cells, tights junctions (prevent fluid movement between cells), gap junctions(channel connects cytoplasm between cells) and adhering junctions(connect cels together)
Hierarchical Level
Atoms Molecules Organelles Cells Tissues Organs Organ System Organism
Epithelial tissue
covers body surfaces and lines the internal cavities such as the gut
connective tissue
holds body parts together and provides structural support
Muscle tissue
moves the body or its parts
Nervous tissue
detects stimuli and relays signals
extracellular fluid
surrounds cells, provides them with nutrients, and collects cellular waste
Plasma
fluid portion of blood
Generation evolution genes
genes that will best help an individual survive and reproduce in their environment are preferentially passed on
Diffusion is only efficient through
short distances
Evolution modifies
existing structures
Epithelium (epithelial tissue)
A sheet of cells that covers the body’s outer surface and lines internal ducts and cavities
Basement membrane
A layer of ECM (extracellular matrix) that is synthesized and secreted by the cells themselves
Simple squamous epithelium
lines blood vessels, the heart, and air sacs of lungs. allows substances to cross by diffusion
simple cuboidal epithelium
lines kidney tubules, ducts of some glands, reproductive tract. Functions in absorption and secretion, movement of materials
simple columnar epithelium
lines some airways, part of the gut. Functions in absorption and secretion, protection.
Cells that move substances across the surface of an epithelium have___
cilia
Glands are derived from_____. What does it do?
Epithelium. Secrete products destined for extracellular function
Exocrine Glands
ducts; external such as tears and internal such as enzymes to small intestine
Endocrine Glands
no ducts; cell products are released by interstitial fluid picked up by blood vessels for delivery to target hormones
Connective tissues
consist of cells and the extracellular matrix that is synthesized and secreted by these cells.
Connects body parts and provides structural and functional support.
Cartilage, bone, tissue and blood
Loose connective tissue
fibroblasts secrete ECM consisting of complex carbohydrates and protein fibers dispersed widely through the matrix
Dense Connective tissue
w/ dense collagen fibers. Ligaments (bone to bone) and tendons (muscle to bone)
cartilage
rubbery extracellular matrix, supports and cushions bones
adipose tissue
fat filled cells, stores energy, cushions and protect organs
Bone
rigid support, muscle attachment, protection , mineral storage, blood production
blood
connective tissue because its cells and platelets descend from stem cells in bone
ATP provides energy that fuels muscle ____
contractions
Skeletal muscle tissue
moves the skeleton (voluntary)
long, started cells with many nuclei
Cardiac muscle tissue
heart muscle (involuntary) striated cells with single nuclei
Smooth muscle tissue
In walls of hollow organs (involuntary), no striations, single nuclei
nervous tissue
detects changes in the internal or external environment, integrates info, and controls the activity of muscle and glands
Nervous tissue consist of specialized
signal cells (neurons) and cells that support them (neuroglial cells)
Neurons
excitable cells with long cytoplasmic extensions; they send an receive electrochemical signals
3 types of neurons
sensory neurons, interneurons and motor neurons which relay command from brain and spinal cord to muscle and glands
Neuroglia (neuroglial cells)
keep neurons in position and provide them with nutrients. They wrap around single sending cytoplasmic extensions of motor neurons and act as insulation that speeds the rate at which signals travel
integumentary system
protects body from pathogens, injuries; controls temp, excretes certain waste
Nervous system
detects external and internal stimuli; controls and coordinates the responses to stimuli. Integrates organ system.
Muscular system
moves body and is internal parts; maintains posture; generates heat by increases in metabolic activity
skeletal system
supports and protects body parts; provides muscle attachment sites; produces red blood cells; stores calcium, phosphorus
Circulatory system
rapidly transports many materials to and from interstitial fluid and cells; helps stabilize internal pH and temperature
Endocrine system
Hormonally controls body functions
Lymphatic system
collects and returns some tissue fluid to the bloodstream; defends the body against infection and tissue damage
Digestive system
Ingests food and water; mechanically, chemically breaks down food and absorbs small molecules into internal environment; eliminates food residues
urinary system
maintains volume and composition of internal environment; excretes excess fluid and waste
reproductive system
females: produce eggs
Male: Transfer sperm to female
integumentary system
consists of skin, connective and adipose tissue. Skin helps conserve water. Helps control internal temperature
Outer epidermis vs deeper dermis
outer contains keratinocytes and inner contains nerves, blood and lymph vessels, hair follicles and glands
epidermis
a stratified squamous epithelium with adhering junction and no extracellular matrix
dermis
consists primarily of dense connective tissue with elastin and collagen fibers.
ex. blood vessels, lymph vessels, sensory receptors, sweat glands, sebaceous glands and hair follicles
sensory receptor
a structure that detects a specific stimulus and sends sensory information to the brain
Negative feedback
process in which a change causes a response that reverses the change
ex. when you get hot you sweat
stimulus–sensory receptors–brain–muscle/gland–response
urinary system
filters water, metabolic wastes and toxins out of the blood, and reclaims water
kidneys
paired, excretory organs that filter blood and adjust level of solutes
marine body fish
hypotonic to its environment
freshwater fish
hypertonic to its environment
kidneys filter blood and form
urine
tight junctions
prevent fluid movement between cells
adhering junction
connects cells together
interstitial fluid
fluid in spaces between cells
coelom
human are bilateral and have a lined body cavity
Urine flows through ___ into a ____ that stores it
ureters; bladder
Urine flows out the body through the _____
urethra
nephron
browman’s capsule
proximal tube
loop of henle (water out, sodium in)
distal tubule (water, sodium out)
blood is delivered to a cluster of _____ inside a bowman’s capsule; fluid is ___ ___ of the blood vessels and filtered
capillaries (glomerulus); forced out
Glomerular filtration
first step in urine formation; occurs in Bowman’s capsule
Tubular reabsorption
returns most water and solutes to the blood
Renal Medulla
fliters in kidneys
Tubular secretion
movement of un-needed substances from the blood of the peritubular capillaries into the filtrate (to excrete as urine); occurs along nephron’s tubules
Concentrating Urine
flows down loop of Henle
Hypothalamus and Thirst
Hypo notifies you when you are thirsty by a hormone
Antidiuretic hormone (ADH)
released by the pituitary when sodium level rise.
Aldosterone
released by the adrenal cortex, increase salt reabsorption in collection ducts; water follows by osmosis; urine is concentrated
Renin
converts angiotensinogen to angiotensin I, converted to angiotensin II, which acts on the adrenal cortex to secrete aldosterone
sits on top of kidney
leads to aldosterone
reabsorption
returns most water and solute to blood
secretion
unneeded stuff released
Normal pH extracellular fluid
7.35-7.45
buffer system
minimizes pH changes by reversibly binding and releasing H+
Kidneys adjust blood pH by ___
H+ secretion; excess H+ leaves the body in urine. only organ that can release hydrogen ion
Ectotherms
body temp changes with environment, regulating by altering position, not metabolism (fish, amphibians and reptiles)
Endotherms
body temp maintained by metabolic heat (birds and mammals)
Heterotherms
can maintain or decrease core temp (some birds and mammals)
Change in body heat =
heat produced+heat gained -heat lost
Thermal radiation
heat is emitted into space surrounding an object
Conduction
heat is transferred by direct contact
convection
heat is transferred by movement of air or water by a breeze
evaporation
heat is lost when liquid is converted to a gas, sweat.
Hypothalamus functions like thermostat to______
maintain core temp via neg feedback
Fever
an increase in body temp regulated by hypothalamus, in response to infection
Torpor
a period of decreased metabolic rate and activity in response to low food availability
Hibernation
a period of dormancy during the cold season where animal is inactive
Estivation
desert lizards become dormant, spent season burrow deep in soil
sensory neurons
detect stimuli and signal interneurons or motor neurons
Have an axon with one end that responds to stimuli
interneurons
process information from sensory neurons and send signals to motor neurons
many dendrites and one axon
motor neurons
control muscle and glands
signals to motor neurons many dendrites and one axon
Central nervous system
brain and spinal cord
Peripheral nervous system
nerves from the CNS to the rest of the body and from the body to CNS
autonomic nerves and somatic nerves control different organs of the body
Nerve
consists of nerve fibers bundled inside a sheath of connective tissue
autonomic nerves
regulative body’s internal state; glands, cardiac muscle…
Somatic nerves
monitor body’s position and external conditions; they control skeletal muscle
Dendrites
receive info from other cells
Axons
send chemical signals to other cells
Mylein sheath
helps move neuron move faster
Voltage gate
postive feedback and allows more sodium to open
Membrane potential
negatively charged proteins and active transport of Na+ and K
Resting membrane potential
an unstimulated neuron. sodium is concentrated higher outside of the cell and potassium is higher inside cell
Action Potential
travels along axon to terminal
Graded potential
slight shift in the voltage difference across the neuron’s membrane
threshold potential
when stimulus in neuron’s trigger zone reaches, sodium channels open
Once threshold level is reached
membrane potential always rises to the same level as action potential peak (all or nothing response)
Outward diffusion of K+
causes membrane potential to decline to a bit below its resting value in a small area
Action potential is
self propagating- sodium ions diffuse to the adjoining region of the axon, triggering sodium gates one after another
Action can only move
one way, toward axon terminals- a brief refractory period after sodium gates close prevents the signal from moving backwards
Neuron’s membrane potential over time:
resting level–threshold level–peak is action potential
Synapse
is the region where an axon terminal send chemical signal to a neuron, muscle fiver or gland cell (postsynaptic cel)
Neuromuscular junction
the synapse between a motor neuron and a skeletal muscle fiber
Chemical synapse
action potential trigger release of signaling molecules (neurotransmitters) from axon terminals
Release of neurotransmitters from vesicles of the presynaptic neuron requires ____
Calcium ions
Myelin sheath
increases the transmission speed of action potential
wraps around neuron
Somatic nervous system
conducts information about the environment to the central nervous system (involuntary)
controls skeletal muscles (voluntary)
Autonomic nervous system
conducts signals to and from internal organs glands
Sympathetic neurons
active in stress or danger (fight or flight response)
Parasympathetic neurons
active in time of relaxation
Spinal cord
connects peripheral nerves with the brain
Central nervous system are made of
brain and spinal cord
Meninges
three membranes that cover CNS
Cerebrospinal fluid
fills central canal
Dorsal roots
sensory info
Ventral roots
motor signals
Reflex
automatic response to a stimulus, a movement or other action that does not require thought
Organizations of brain
forebrain, midbrain, hindbrain.
Weight of human brain
3 pounds or 1240 grams
Medulla Oblongata
connects the spinal cord
Pons
adjoins the medulla, it affects breathing and has connections to midbrain
Cerebellum
balance, motor skills and language
Brain stem
reflex behaviors
Cerebrum
main processing center. thought and language.
Corpus callosum
signals two hemispheres of cerebrum
Thalamus
receives sensory signals, sorts them and sends them to proper region of the cerebral cortex
Hypothalamus
center of homeostatic control of internal environment. Regulates thirst, appetite, sex and temp
Cerebral cortex
outermost gray matter, controls voluntary activity, sensory perception, abstract thought, language and speech
4 lobes of brain
frontal, temporal, occipital and parietal
Primary motor cortex
controls skeletal muscles
primary somatosensory cortex
front of the parietal lobe receives sensory input form the skin and joints
limbic system
governs emotion, memory and and gratifying behaviors.
includes: hypothalamus, hippocampus, amygdala, and cingulate gyrus
emotional state influences
long term memory
Neuroglial cells
act as framework that holds neurons in place
Action Potential speed
120 m/s vs 10m/s for non myelinated nerves
Oligodendrocytes
make myelin sheaths
microglia
have immune sytem functions
astrocytes
stimulate formation of the blood brain barrier
ependymal cells
line brain cavities
Hormones
internal secretions carried by the blood that influence the activities of specific body organs
Hormone action
signal is transduce (charged into a form that affects target cell behavior
hypothalamus is the main center for control of
the internal environment – it connects structurally and functionally with the pituitary gland
pituitary gland
The posterior lobe secretes hormones made in the hypothalamus
The anterior lobe makes its own hormones
Antidiuretic hormone (ADH)
affects certain kidney cells
Manufactured by hypothalamus, stored and released by posterior pituitary gland. Controls water
Oxytocin (OT)
triggers muscle contractions during childbirth
Releasing hormones
encourage secretion of hormones by target cells
Inhibiting hormones
reduce secretion of hormones by target cells
anterior pituitary produces hormones of its own:
Growth hormone (GH)Thyroid-stimulating hormone (TSH
Acromegaly
bones getting bigger as you age
The thyroid gland
located at the base of the neck, regulates metabolic rate
Parathryoids
regulate calcium levels
Needed for bone
adrenal cortex
secretes steroid hormones and small amounts of sex hormones
cortisol
affects metabolism and the stress response
adrenal medulla
contains specialized neurons of the sympathetic division that release epinephrine and norepinephrine, which stimulate the fight-flight response
Ovaries produce
estrogens and progesterone
hypothalamus and anterior pituitary control secretion of
sex hormones by gonads
The hypothalamus produces gonadotropin-releasing hormone (GnRH)
which causes the anterior pituitary to secrete follicle-stimulating hormone (FSH) and luteinizing hormone (LH
