BIO

An AP is initiated in the post-synaptic neuron only if the membrane potential becomes more positive and exceeds a certain threshold (−__ mV)

-55

In spermatogenesis, some of the daughter cells produced from mitotic divisions of spermatogonia become primary spermatocytes. They then become mature sperm via meiosis, a process involving two rounds of cell division known as meiosis I and II. A primary spermatocyte that undergoes meiosis I yields _ identical haploid cells labeled secondary spermatocytes. Each secondary spermatocyte then undergoes meiosis II to produce _ identical haploid spermatids that develop into mature sperm.

2 4

In eukaryotic organisms, gametes (eggs, sperm) form via meiosis, a process of cellular division resulting in the production of 4_ haploid (1N) daughter cells from _ diploid (2N) parental cell. Meiosis occurs in two stages, meiosis I and meiosis II, each of which is composed of prophase, metaphase, anaphase, and telophase followed by cytokinesis (cell division):

4 1

nucleotides are linked to one another by phosphodiester bonds between the sugar base of one nucleotide and the phosphate group of the adjacent nucleotide in a way that the _' end bears a phosphate, and the _' end a hydroxyl group.

5' 3'

The hormone ____ stimulates the adrenal cortex to secrete glucocorticoids

ACTH

When acetylcholine (ACh) is released by the motor neuron at the neuromuscular junction, the following occur: ___ binds and opens ligand-gated ion channels in the sarcolemma (the plasma membrane of the muscle cell). ____ flows down its electrochemical gradient and into the cell through the channel, resulting in depolarization of the sarcolemma and generation of an action potential that propagates along the muscle fiber in all directions. At certain locations along the muscle fiber, the sarcolemma burrows deep into the cells, forming a channel known as the transverse (_) tubule, which brings depolarizing current close to the sarcoplasmic reticulum (SR). The SR is a specialized smooth endoplasmic reticulum responsible for regulating cytosolic _____ levels within the muscle cell. Action potential propagation through the T tubule ultimately leads to the opening of Ca2+ channels in the SR membrane. Because Ca2+ is more highly concentrated inside the SR than in the cytosol, the opening of these channels results in Ca2+ flowing down its concentration gradient and into the cytosol. Cytosolic Ca2+ ions then bind to __________, which allows the actin and myosin filaments of the sarcomere to slide across one another. The sliding of the filaments results in shortening of the sarcomere and overall muscle contraction. The Ca2+ channels in the SR membrane close when the depolarizing stimulus ceases. Active transport Ca2+ pumps sequester the Ca2+ back into the SR, which allows the muscle to return to its relaxed state as cytosolic Ca2+.

ACh Na+ T tubule & Ca2+ troponin For a skeletal muscle cell to contract, Ca2+ must be released into the cytosol from the sarcoplasmic reticulum (SR). Ca2+ release is induced when a depolarizing current (action potential) runs along the sarcolemma and travels down the T tubules. This current causes the nearby SR to open its Ca2+ channels, allowing Ca2+ ions to flow into the cytosol and induce the sarcomeric actin-myosin interactions required for muscle contraction.

At the neuromuscular junction, the entry of calcium ions into presynaptic neurons leads to the release of _____________ from the presynaptic vesicles and into the synaptic cleft, where it then binds its receptor on the muscle fiber membrane.

ACh (acetylcholine

An open reading frame (ORF) is a set of codons within a strand of mRNA that can be translated by a ribosome. An ORF begins with a start codon (___) and ends with a stop codon (___, ___, or ___). The start and stop codons must be in the same reading frame.

AUG UAA,UAG,UGA

_____________, which is produced by the adrenal cortex, causes Na+reabsorption by kidney tubules. This decreases Na+ levels in the urine Increases blood volume & pressure

Aldosterone

The adrenal glands are endocrine organs located on top of the kidneys that secrete hormones mediating the stress response (physiological changes that allow the body to cope with and react to physical, social, and emotional stressors). The adrenal cortex secretes the hormones cortisol and aldosterone, and the adrenal medulla secretes the hormones epinephrine and norepinephrine. _______________, secreted from the adrenal cortex, stimulates Na+ reabsorption in the kidneys, leading to increased water retention due to osmosis. Increased water retention increases blood volume, which in turn leads to an increase in blood pressure. _______________ & ______________ secreted from the adrenal medulla, function to mobilize the body under extreme stress and promote rapid information processing in part by maximizing blood flow to organs essential for survival. Norepinephrine and epinephrine achieve this effect by promoting the following changes in blood vessel diameter that lead to altered blood pressure: Vasoconstriction (narrowing) of blood vessels supplying the intestines, kidney, and other abdominal organs decreases blood flow to these organs and conserves oxygen/nutrients for other tissues. Vasodilation (widening) of blood vessels leading to the heart and skeletal muscles increases oxygen/nutrient delivery to these organs.

Aldosterone Norepinephrine and epinephrine,

albumin is the main protein of human blood plasma. It binds water, cations (such as Ca2+, Na+ and K+), fatty acids, hormones, bilirubin, thyroxine (T4) and pharmaceuticals (including barbiturates): its main function is to regulate the oncotic pressure of blood.

An increase in plasma albumin will upset the osmotic balance because the blood will become hypertonic with respect to the tissue. Water will have to flow into the bloodstream to reestablish equilibrium. One of the causes of edema, increased fluid in body tissues, is a decrease in the plasma protein level.

_ lymphocytes are cells that bind and engulf a foreign antigen. The antigen is broken down into fragments within the B lymphocyte, and these fragments are transported to be displayed on MHC proteins present on the cell membrane. A helper _ cell binds the foreign antigen presented by the B lymphocyte and releases signaling molecules (cytokines) that induce division of the B lymphocyte into many identical cells, some of which differentiate to secrete antibodies against the invading pathogen.

B T

Muscle tissue can be classified as cardiac, skeletal, or smooth. ______ muscle is striated, contains 1-2 nuclei, has intercalated discs, and is under involuntary control. _________ muscle is striated and under voluntary control, and is multi-nucleated ______ muscle is not striated, uninucleated, and under involuntary control

Cardiac Skeletal Smooth

____________ evolution leads to similar characteristics in distantly related species that are exposed to similar environmental pressures. ex flying squirrlel and flying lizards ____________ evolution also leads to similar characteristics in species found in similar environments but occurs in species with a more recent common ancestor. ____________ evolution leads to unique characteristics in somewhat closely related species that face contrasting environmental

Convergent Parallel Divergent

____________ provide tensile strength to epithelial cell sheets by anchoring the cytoskeletons, specifically the intermediate filaments, of two cells together.

Desmosomes

___________ viruses have a membrane, or phospholipid bilayer, generally derived from the cell membrane of the host. The phospholipid bilayer of enveloped viruses surrounds the capsid and often contains host-derived proteins, allowing the virus to better evade the immune system and gain entry into the host cell. In contrast, ___________ (naked) viruses lack a phospholipid bilayer.

Enveloped nonenveloped

The synthesis and secretion of hormones from the anterior pituitary is regulated by the release of neurohormones into the blood from neurons located in the hypothalamus, and secreted into the hypophyseal portal system

FLAT-PEG

Sertoli cells support and nourish the spermatocytes and promote the process of spermatogenesis. Spermatogenesis would not occur without Sertoli cells. The two hormones that directly stimulate Sertoli cells are ____ and ______________. Thus they are essential for spermatogenesis to occur.

FSH & testosterone

____ junctions are cell-cell junctions that mediate communication between cells. Protein channels (connexons) in one cell align with complementary channels in another cell to form pores that facilitate the passive and bidirectional exchange of ions and small solutes. Gap junctions are found in cell populations that depend on coordinated activity, such as smooth muscle, cardiac muscle, or neural tissue.

Gap junctions

Chromatin structure affects gene expression by regulating transcription. __________________ is tightly wound DNA characterized by low levels of histone acetylation and _____ levels of DNA methylation. Genes in these regions are considered silenced because the DNA is so tightly packed that it is inaccessible to the transcription machinery. In contrast, ______________ is marked by high levels of histone acetylation and _______ levels of DNA methylation. This makes euchromatin looser and the DNA more accessible to the transcription machinery, allowing gene expression.

Heterochromatin; high euchromatin; low

Difference btwn Anaphase 1 and anaphase II of meoisis:

In anaphase II sister chromatids (not homologous chromosomes) are pulled to opposite poles of the cell by the meiotic spindle.

Microtubules are structural cytoplasmic filaments composed of tubulin subunits. These filaments have a number of critical functions, including serving as tracks for intracellular transport of organelles and vesicles. The movement of intracellular cargo along microtubules is mediated by two motor proteins: _______: Moves intracellular cargo along microtubules in anterograde axonal transport (ie, away from the nucleus and toward distal sites). _______: Participates in retrograde axonal transport of intracellular cargo (ie, from distal sites toward the nucleus)

Kinesin Dynein

A surge in __ hormone and follicular rupture are necessary steps for ovulation to occur. It provides the necessary stimulus for follicular rupture and the release of a secondary oocyte into the fallopian tube. Because these steps must happen before

LH

Ligaments and tendons are rope-like, dense connective tissue structures. ___________ attach bones to other bones __________ generally attach bones to muscles

Ligaments tendons

The ovaries are female reproductive structures that produce gametes and secrete sex hormones. _____________ or female gamete (ovum) production occurs in the ovaries as follows: In utero, oogonia (ovarian stem cells) of the female embryo rapidly multiply via mitosis to generate _____________ oocytes, which are surrounded by specialized cells that form a saclike structure known as a follicle. Female gametes must undergo meiosis to mature. Primary oocytes begin the first meiotic division but become arrested at ____________ I until puberty. At puberty, hormonal changes during each menstrual cycle result in a single follicle being selected to continue meiosis I. Completion of meiosis I produces one haploid ____________ oocyte and one small _______ body that ultimately degenerates. The secondary oocyte begins the second meiotic division but is arrested at _____________ II. In the ovulation phase of the menstrual cycle, the follicle ruptures and the secondary oocyte is released into the abdominal cavity. The secondary oocyte enters the __________ tubes, where it can be fertilized by a sperm cell. If fertilization occurs, the secondary oocyte will complete meiosis II to form one large ovum (fully mature) and a second polar body that degenerates

Oogenesis primary oocytes prophase I secondary oocyte & 1 polar body metaphase II fallopian tubes

During bone remodeling, osteoclasts break down (resorb) old bone and osteoblasts deposit new bone. ____________ promote the precipitation of calcium and phosphate from the bloodstream and their transfer and incorporation into the bone matrix. ____________ secrete proteolytic enzymes and acids that break down the organic and mineral components of bone. As the bone matrix is broken down, mineral components (eg, calcium) are reabsorbed into the bloodstream.

Osteoblasts osteoclasts

Posterior pituitary hormones are synthesized in hypothalamic neurons and undergo anterograde axonal transport to the posterior pituitary. The secretion of stored posterior pituitary hormones from the axon terminals is mediated by depolarization of the nerve terminals and sent out exocytosis of neurosecretory vesicles The 2 Hormones released by posterior pituitary = ____________ & ________________

Oxytocin & Vasopressin

Cells take up their surrounding environment via endocytosis, which includes mechanisms of phagocytosis, pinocytosis, and receptor-mediated endocytosis. ____________, also called "cell eating," occurs when cells engulf external particles by extending portions of their membrane to reach around the particle ___________ is a nonspecific process (ie, does not require receptor binding) that involves the continuous invagination of the cell membrane to take up extracellular fluid ________-_________ endocytosis, in which an external ligand binds specific receptor proteins on the cell surface. This binding induces the plasma membrane to bud inward toward the cytosol before pinching off as a vesicle that contains both the ligand and its receptor.

Phagocytosis Pinocytosis receptor-mediated

_____________ are a type of hydrolase that break peptide bonds by hydrolysis (addition of water). ____________ rearrange functional groups within a molecule but do not catalyze redox reactions. ________________ are a type of transferase that break bonds by adding phosphate, as in glycogen degradation.

Proteases Isomerases Phosphorylases

The gall bladder is an organ that stores bile produced by the liver. The major dissolved components of bile are breakdown products of hemoglobin such as bilirubin and bile salts. The bile salts are amphipathic Bile salts allow dietary fats (and oils), which do not dissolve in the watery digestive juices, to form an emulsion of tiny droplets dispersed in the digestive juices. Since triglycerides are hydrophobic fats, bile would aid in their digestion

Removal of the gall bladder would have no effect on digestion of proteins, polysaccharides, or lactose.

____ protein is found on the Y chromosome, which is present only in males, and its expression induces the development of the male gonads (testes). When the protein is produced, fetuses will develop as male, but in the absence of SRY, fetuses will develop as female.

SRY

The ______________ reticulum (SR) is a muscle fiber organelle that tightly regulates intracellular _____________ concentration. The release of calcium from the SR promotes muscle fiber ____________ whereas the transport of calcium into the SR promotes and maintains muscle fiber _____________.

Sarcoplasmic Reticulum Calcium Contraction Relaxation

_________ blotting is a technique used to detect and measure the concentration of DNA in a cell. ____________ blotting is a biomolecular assay used to detect and measure the concentration of specific RNA molecules within a cell or tissue sample

Southern Northern

In cell-mediated immunity, _ lymphocytes (cells) recognize and mount immune responses against foreign antigens displayed by other cells on specialized surface proteins called major histocompatibility complex (MHC) proteins.

T

_____ junctions are cell-cell junctions that prevent water and solutes from diffusing between cells and across the epithelial cell layer. These junctions form a watertight seal that fully encircles the apical end of every cell in the basal epithelial sheet. They serve as a barrier and separate tissue space; they are found in a number of tissues, including skin, gastrointestinal tract, and testis

Tight

______ ____________ _ is the main input of the citric acid cycle

acetyl coenzyme A

Corticosteroids (glucocorticoids and mineralocorticoids) are steroid hormones released by the adrenal cortex. The release of cortisol from the adrenal cortex is mediated by the secretion of __________________ (ACTH) hormone from the anterior pituitary.

adrenocorticotropic (ACTH)

Circulating blood enters the glomerulus through the ________ arteriole and exits through the _________ arteriole. The degree of vascular constriction of these two arterioles controls the rate of blood flow into and out of the glomerulus, thereby affecting the GFR through changes in glomerular hydrostatic pressure.

afferent efferent

Key difference btwn mitosis and meiosis is during _____________. During this phase in mitosis, sister chromatids are pulled apart at the centromeres, each becoming an independent chromosome in the two diploid daughter cells. During anaphase I of meiosis I, homologous pairs of chromosomes are separated into the two daughter cells. However, each chromosome still consists of two sister chromatids joined at centromere. It is not until anaphase II of meiosis II that the centromere is split and the sister chromatids separate.

anaphase

Meiosis I: In prophase I, the nuclear envelope of a diploid parental cell disintegrates and homologous chromosomes (each consisting of two sister chromatids) pair up. In metaphase I, these chromosomes align in the middle of the cell (ie, at the metaphase plate). The chromosomes are pulled to opposite poles of the cell by the meiotic spindle in __________ I. The nuclear envelope then reforms in telophase I and the cytoplasm of the cell divides (cytokinesis) to yield _ haploid daughter cells.

anaphase I 2

Gamete formation requires cellular division by meiosis I and meiosis II, in which homologous chromosomes and sister chromatids, respectively, are separated. In the absence of recombination, maternal and paternal alleles are separated from each other during ___________ I, and identical alleles on each sister chromatid are separated from each other during ___________ II.

anaphase I anaphase II

The _________ pituitary gland secretes several hormones, including follicle-stimulating hormone (FSH), luteinizing hormone (LH), adrenocorticotropic hormone (ACTH), thyroid-stimulating hormone hormone (TSH), and Prolactin, Endorphins, and growth hormone (GH). FLAT-PEG FLAT=______ hormones- meaning that they act upon other endocrine glands as their target organs. PEG= ______ hormones- meaning they act directly on non-endocrine organs

anterior tropic direct Specifically, GH promotes processes such as tissue growth and utilization of fats. In addition, pituitary release of LH and FSH regulates reproductive function in males and females. In females, FSH and LH stimulate follicle maturation, ovulation, and estrogen production. In males, spermatogenesis and testosterone production are regulated by FSH and LH, respectively.

When the RNA molecules hybridize, the antisense molecule would line up in an _____________ fashion with the sense molecule, meaning its 3′ end would line up with the 5′ end of its complement ex. 5′-CGAUAC-3′ 3′-GCUAUG-5′

antiparallel

Diabetes can promote weight loss, increased thirst, fatigue but NOT loss of ________

appetite

Specialized valves facilitate unidirectional blood flow through the heart. _________________- (AV) valves allow blood to flow from the atria to the ventricles, and ________________ (SL) valves allow blood to flow from the ventricles into the arteries.

atrioventricular semilunar

The PNS consists of all nerves and neurons located outside the CNS. The peripheral nervous system has two branches: the __________(involuntary) nervous system and the __________ (voluntary) nervous system.

autonomic somatic

The spleen has extensive capillary networks through which ______ is filtered. White blood cells housed within the spleen recognize and bind foreign antigens in the blood, mounting immune responses against these circulating pathogens. In addition, spleen macrophages remove and destroy old and damaged red blood cells.

blood

Two factors that normally determine the blood pressure are the _______ output and the ___________ to blood flow. The resistance to blood flow is primarily determined by the caliber of the small arteries, arterioles, and precapillary sphincters. Thus blood pressure equals total peripheral resistance times cardiac output, a relationship analogous to Ohm's law for electrical circuits.

cardiac output resistance to blood flow

During the stress response, ________________ secreted from the adrenal medulla act to promote the "fight-or-flight" response. Some effects of catecholamines include redirected blood flow to maximize the delivery of oxygen and other nutrients to organs essential for immediate survival (eg, brain, lungs, skeletal muscles), increased heart rate, and dilated airways.

catecholamines

Microtubules are involved in intracellular transport. The microtubules involved in this process originate near the nucleus on organelles called __________ and radiate out toward the plasma membrane. Fucntions: Microtubules form the mitotic spindle during cell division and are essential for cell motility as they form the core of cilia and flagella. Microtubules also facilitate transport of vesicles such as endosomes and other organelles from one location in the cell to another.

centrioles

Bacteria and archea have _________ chromosomes, while eukaryotic have ____________ chromosomes.

circular linear

When the plasma membrane is at its resting potential, the voltage-gated K+ channels and the voltage-gated Na+channels are _______. As triggering events bring the membrane up to its threshold potential, the voltage-gated Na+ channels _____ and cause further depolarization of the membrane by allowing Na+ to flow into the cell and the voltage-gated K+ channels are ______ during the depolarization phase of an action potential.

closed open closed

Breakdown of glucose proceeds first by glycolysis, which occurs in the __________, then by oxidation in the citric acid (Krebs or tricarboxylic acid) cycle, which occurs in the matrix of ______________

cytoplasm mitrochondria

In prokaryotes, transcription occurs in the _________ of the cell.

cytosol

Oxygen intake remains elevated after exercise due to the increased demand in muscle cells for oxygen to replenish ATP, creatine phosphate, and glycogen stores and restock myoglobin with oxygen. The amount of additional oxygen consumed is called the excess post-exercise oxygen consumption, or oxygen _____.

debt

Exercise promotes the insulin-independent uptake of glucose and thus it will _______ blood glucose levels in both Type 1 and type 2 diabetes

decrease

The genetic code is considered "_____________" because more than one codon can code for the same amino acid. This occurs because the 3rd position of the mRNA codon and tRNA anticodon can undergo nontraditional base pairing, allowing a single tRNA molecule to bind different codons.

degenerate

Acetylcholine is released at the neuromuscular junction where it binds to receptors on the muscle cells and, depending on the type of muscle cell, causes depolarization or hyperpolarization of the cell membrane. In skeletal muscles, acetylcholine binds to its receptors, which leads to ________________ of the muscle cell membrane and muscle contraction.

depolarization

The movement of sodium ions into a neuron during an action potential results in opening of more voltage-gated sodium channels, causing further ______________ of the membrane potential.

depolarization

Genetic ______ is the fluctuation of allele frequencies within a population due to chance events. This can lead to random loss of alleles within a population. In general, low-frequency alleles have an increased probability of being eliminated by random events than do high-frequency alleles. Because alleles on the _ chromosome exist at the lowest frequencies, they are most susceptible to loss by random chance alone.

drift Y

The ______________ system is a series of compartments that work together to package, label, and ship proteins and molecules

endomembrane

The secretory pathway involves the processing of proteins as they go through the ______________ reticulum and the ______ apparatus. After processing in the Golgi, proteins destined for the cell membrane are packed into secretory vesicles, which fuse with the plasma membrane. Other organelles, such as the nucleus, mitochondria, and peroxisomes, are not involved in the secretory pathway, and most of their proteins are translated in the cytosol.

endoplasmic Golgi apparatus

Depending on the neurotransmitter's effect on the post-synaptic neuron, synapses can be classified as excitatory or inhibitory. At an __________ synapse, the pre-synaptic neuron releases neurotransmitters that cause an influx of positively charged ions (Na+) into the post-synaptic neuron. These ions cause the resting membrane potential of the post-synaptic neuron to become more positive, or to _________, which promotes AP initiation.

excitatory depolarize

Severe dehydration greatly reduces the _________ of filtrate moving through the nephrons of the kidney. If it is too drastically reduced, the kidney will be unable to effectively do its job of filtering and maintaining homeostasis within bodily fluids

fluid/blood volume

Blood is filtered in the glomerulus by high hydrostatic (blood) pressure, which forces excess fluid and waste products (filtrate) across the porous endothelium and into Bowman's space. Proteins and cells are too large to pass through the pores. The volume of fluid filtered through the kidney per unit time is known as the glomerular filtration rate (GFR).

glomerular filtration rate

Filtrate is formed as fluid passes from the glomerular capillaries through the glomerular membrane into the Bowman's capsule. This region of the nephron is known as the ____________

glomerulus

_________________ act on skeletal muscle causing the breakdown of muscle proteins

glucocorticoids

______________________ is the pathway for the synthesis of glucose from other metabolic compounds and thus it is activated when the body's stores of carbohydrates are low

gluconeogenesis

The anterior pituitary secretes _________ hormone to induce tissue growth, including bone development. GH can stimulate osteoblast activity to increased bone matrix deposition ___________, a hormone secreted by the pancreas, raises the concentration of glucose in the blood by promoting glycogenolysis

growth hormone Glucagon

ATPase activity results in ATP __________. ATP hydrolysis produces ___ and inorganic ____________

hydrolysis ADP +Pi Pi=inorganic phosphate

If the cells membrane potential ______________, it becomes more positive and promotes an AP. If the cells membrane potential ________________, it becomes more negative and inhibits an AP.

hyperpolarizes Depolarizes

__________ dominance between alleles results in a blended or intermediate phenotype in heterozygous individuals. A common example of incomplete dominance is a cross between homozygous red flowers (RR) and homozygous white flowers (WW) producing heterozygous offspring (RW) that are pink.

incomplete dominance blended

Parathyroid hormone acts to ____________ blood calcium levels, while calcitonin acts to___________ blood calcium levels

increase decrease Which hormone puts calcium into bone and which gets rid of it is? Calcitonin-in, parathroid-rid.

________ synapses release neurotransmitters that affect the post-synaptic neuron by causing either an influx of negative ions (Cl−) or an efflux of positive ions (K+). The exit of positive ions or entry of negative ions into the post-synaptic neuron causes the cell's membrane potential to become more negative, or to __________, which inhibits AP initiation.

inhibitory hyperpolarize

Cells of the _______ immune system can rapidly and nonspecifically recognize and destroy foreign antigens. The ________ immune system, subdivided into cell-mediated and humoral immunity, comprises cells that recognize specific antigens and mount more specialized immune responses against invading pathogens.

innate adaptive

The pancreas regulates blood glucose concentration by secreting ________ & __________. Insulin is secreted in response to high blood glucose levels to promote glycogen formation in the liver and uptake of glucose by cells. In contrast, glucagon is secreted in response to low glucose levels to promote gluconeogenesis and glycogen breakdown.

insulin and glucagon

Eukaryotic cells have a unique mechanism for processing messenger RNA (mRNA). Eukaryotic mRNA is initially transcribed as pre-mRNA, containing both introns (noncoding sequences) and exons (coding sequences). Following transcription, the spliceosome (an RNA and protein complex) removes ________ from the pre-mRNA molecule to form mature mRNA in a process known as RNA splicing. This mature mRNA is transported out of the nucleus and into the cytoplasm, where it is translated into protein.

introns

The __________ is involved in the regulation of acid-base balance, blood pressure, water balance, and the removal of nitrogenous wastes.

kidney

Cell membranes are composed largely of phospholipids, which act as a fluid that allows other membrane components such as transmembrane proteins, glycoproteins, cholesterol, and glycolipids to migrate through this environment __________. Accordingly, the structure of the animal cell membrane is known as the fluid mosaic model.

laterally

Clotting factors (mainly synthesized in the ____) are specialized proteins that become activated in response to platelet aggregation and signaling factors outside the vessel. Activated clotting factors induce processes that lead to the formation of the enzyme _______. This enzyme induces protein strands (ie, ____) to form an adhesive mesh-like structure over the platelet plug, reinforcing the clot.

liver thrombin fibrin

Bacteriophages use the host cell's machinery and resources to replicate their genome and synthesize viral proteins to form new virions. Phages with a ____ life cycle replicate rapidly and release progeny via lysis of the host cell. In contrast, phages with a ___________ life cycle integrate their genome with the host genome and replicate as the cell divides

lytic lysogenic

____ is only directly involved in the process of translation, and not transcription

mRNA

_______________ and _________ cells engulf foreign antigens (via phagocytosis) and present these antigen fragments on the MHC proteins found on their cell membrane. Upon binding these antigens, helper T cells release cytokines that enhance other immune responses, including the phagocytotic activity of macrophages and the activation and proliferation of cytotoxic T cells, immune cells that release toxins to induce apoptosis in infected cells.

macrophages & dendritic cells

Glomerular filtrate is most concentrated in the ____________ portion of the collecting duct

medullary

The kidneys are composed of functional units called __________. In these, the glomerular capillaries (which are collectively known as the glomerulus), Bowman's capsule, the renal tubule, and the collecting duct work together to filter blood and concentrate the waste products as urine.

nephrons

Chromosomal ________________ during anaphase I may produce one daughter cell with an extra homologous chromosome (24 chromosomes) and one daughter cell missing a chromosome (22 chromosomes)

nondisjunction

Mature Erythrocytes (red blood cells) do not contain a ___________ or _____________ (organelles)

nucleus or mitochondria

During repolarization, ligand gated K+ channels _____, allowing K+ to flow out of the cell and repolarize the membrane by returning the membrane to near its resting potential and the the voltage-gated Na+ channels are _________ during this phase.

open closed

Decreased osteo____ activity and increased osteo____ activity result in bone loss

osteoblast osteoclast

The Na+K+ ATPase transports 3 sodium ions ___ of the cell and 2 potassium ions ____ the cell with each ATP hydrolyzed

out into

Disulfide bonds form in proteins when two cysteine residues are oxidized (lose electrons) to form cystine. They must be reduced (gain electrons) for the bond to break. Enzymes that catalyze oxidation-reduction reactions (transfer of electrons) are collectively known as ____________________.

oxidoreductase

Blood in the pulmonary artery is lower in _________, higher in _______ and has a _______ pH than arterial blood in the aorta. This is because the blood in the pulmonary artery, unlike blood in other arteries, is essentially the same as venous blood

oxygen CO2 lower

The left atrium receives _________________ blood returning from the lungs and transfers this blood into the left ventricle, a highly muscular chamber that pumps blood throughout the entire body via systemic arteries. _______________ blood returns to the heart via systemic veins and fills the right atrium, which transfers blood into the right ventricle. Right ventricular contraction pumps this type of blood to the lungs via the pulmonary arteries.

oxygenated deoxygenated

Parathyroid hormone (PTH) and calcitonin are hormones that maintain calcium homeostasis by regulating calcium absorption and bone remodeling. Specifically, low blood calcium levels lead to secretion of _____________, which then promotes several processes to elevate blood calcium levels. _____________ is secreted by the thyroid gland in response to high blood calcium levels and opposes PTH activity by decreasing the activity of osteoclasts and blood calcium levels

parathyroid hormone (PTH) Calcitonin

The following mechanisms contribute to maintenance of the resting membrane potential: Protein channels in the cell membrane enable certain ions to move down their concentration gradient across the membrane. For example, in resting neurons, potassium leak channels help maintain the membrane potential by enabling the __________ transport (without using energy) of K+ out of the cell. Because the membrane is more permeable to K+ than to Na+ (ie, _________ permeability), the resting membrane potential of neurons is approximately −70 mV, which is close to the negative equilibrium potential of K+ _______ transport pumps embedded in the outer membrane of neurons hydrolyze adenosine triphosphate (ATP) to provide energy to transport molecules against their concentration gradient. For example, sodium-potassium pumps (Na+K+ ATPase) transport 2 K+ into the cell for every 3 Na+ moved out of the cell. This is important for maintaining the unequal concentration of ions across the membrane; without active transport pumps, leakage of ions through the cell membrane would eventually result in equilibration and a membrane potential of 0 mV.

passive transport selective permeability Active transport

The inner membrane of a mitochondrion is analogous to the ________ membrane of a prokaryote. The enzymes for oxidative phosphorylation are embedded in the inner membrane.

plasma

Neurotransmitters traverse the synaptic cleft to bind receptors on the _____-synaptic membrane. This binding causes the opening of ion channels, facilitating the movement of charged ions into or out of this cell. As a result, the resting membrane potential (−__ mV) of the post-synaptic neuron is altered.

post-synaptic membrane -70

Neurotransmitters bind to a receptor on a ________________ membrane within the CNS.

postsynaptic

Oogenesis (oocyte production) begins before birth, not at puberty, in the female gonads (ie, ovaries). In the female embryo, oogonia (stem cells) undergo mitosis to produce _______ oocytes. Each primary oocyte is surrounded by a saclike structure called a follicle. Although they must also undergo meiosis to mature, primary oocytes begin meiosis I but become arrested at ________ I until puberty. At puberty, one primary oocyte is selected during each menstrual cycle to complete meiosis I.

primary oocytes prophase I

In __________ I of meiosis, homologous chromosomes recognize each other and line up side by side during synapsis. ____________ over result in daughter cells with chromosomes containing combinations of alleles that differ from those in the parent cell, leading to eukaryotic genetic recombination and increased genetic diversity.

prophase I crossing over

The pancreas produces several _______________enzymes, which are released into the small intestine where they are converted to their active forms of trypsin, chymotrypsin, and carboxypeptidase. Pancreas does not produce gastric juices (stomach releases them into duodenum Liver secretes bile salts into gallbladder

proteolytic enzymes

The lymphatic system: The bone marrow, a spongy tissue lining the inside of bones, is responsible for the production of ___ blood cells and ______ blood cells (eg, lymphocytes) from hematopoietic stem cells. The thymus receives immature _ lymphocytes migrating from the bone marrow and facilitates their maturation. Lymph nodes, organs clustered along lymph vessels, filter lymph as it flows through the lymphatic system. ____________ housed within lymph nodes identify a variety of pathogens in lymph and destroy them via phagocytosis.

red & white T lymphocytes Macrophages

During the diastole (bottom) phase, the heart _______ and fills with blood returning to the heart via the veins. Because blood is not pumped from the heart during diastole, the volume of blood flowing through the arteries is lower, ____________ pressure on the arterial walls. Therefore, arterial blood pressure is lowest during diastole and is measured as the diastolic blood pressure. During the systole (top) phase, the heart ________ and blood is forced from the heart into the arteries. This increased volume of blood flowing through the arteries on contraction of the heart exerts __________ pressure (ie, hydrostatic pressure) on the arterial walls. Accordingly, arterial blood pressure is highest during systole and is measured as the systolic blood pressure.

relaxes decreasing contracts increased

Na+K+ ATPase functions to ________ the resting membrane potential by moving the ions against their concentration gradients.

restore

Reduced volume of blood flowing into the _____ ventricle cause a backup of blood in the right atrium and systemic vessels and result in edema in the abdomen and legs.

right

Molecules can cross biological membranes by active or passive transport: Active transport involves a molecule moving against its concentration gradient and requires energy input (eg, ATP). Passive transport involves molecules diffusing down their concentration gradient and requires no external energy. Passive transport can be divided into _________ diffusion, in which molecules cross membranes directly, and ____________ diffusion, in which molecules must go through protein channels.

simple facilitated

Meiosis II: A process similar to meiosis I occurs in this stage, with the exception that it occurs in the previously formed haploid daughter cells. Following nuclear envelope disintegration in prophase II, chromosomes align at the metaphase plate during metaphase II. However, in anaphase II _______ chromatids (not homologous chromosomes) are pulled to opposite poles of the cell by the meiotic spindle. Reformation of the nuclear envelope in telophase II and cell division (cytokinesis) of each cell yields four haploid daughter cells.

sister

____-twitch (type 1) oxidative fibers contract at a slow rate due to the lesser frequency at which the myosin heads hydrolyze ATP during each contractile cycle. These fibers produce ATP via aerobic respiration. Therefore, they contain many mitochondria that use oxygen in the electron transport chain to produce large amounts of ATP (energy), making these fibers more fatigue resistant. Type 1 fibers receive oxygen from their extensive capillary networks and high concentrations of myoglobin.

slow-twitch

The female ovum is analogous to the male __________________.

spermatozoa

Cardiac output is equal to (_________ volume x _______ rate) and determines the amount of blood pumped into the system by the heart per unit time.

stroke volume heart rate

A synapse, which can be chemical or electrical, is a junction formed between the axon terminal of a pre-synaptic neuron and the dendrites of a post-synaptic neuron. An AP travels down the axon of a pre-synaptic neuron until it reaches the axon terminals. At chemical synapses, the AP induces the release of neurotransmitters from the pre-synaptic neuron into the _______ cleft (ie, the space between the pre-synaptic axon terminal and the post-synaptic dendrite).

synaptic cleft

In humans, cholesterol is a precursor to the steroid hormone __________________

testosterone

Electrical depolarization caused by action potential propagation leads to the contraction of skeletal muscle fibers. As extensions of the plasma membrane that penetrate deep into muscle fibers, ____________ tubules are specialized muscle fiber structures (similar to axons) that facilitate action potential propagation throughout individual muscle fibers.

transverse (T) tubules

Unlike in spermatogenesis, meiosis I in oogenesis yields two haploid cells of ________ size, the larger one being a ___________ oocyte and the smaller one being a ______ body that eventually degenerates

unequal secondary oocyte polar body