370 likes | 568 Views
Sample Test Questions from Cell Cycle. If there are 20 chromatids in a cell, how many centromeres are there? 20 80 10 30 40. Sample Test Questions from Cell Cycle.
E N D
Sample Test Questions from Cell Cycle • If there are 20 chromatids in a cell, how many centromeres are there? • 20 • 80 • 10 • 30 • 40
Sample Test Questions from Cell Cycle • If there are 20 chromatids in the cell at metaphase, how many chromosomes are there in each daughter cell following cytokinesis? • 80 • 10 • 30 • 20 • 40
Sample Test Questions from Cell Cycle • If a cell has 8 chromosomes at metaphase of mitosis, how many chromosomes will it have during anaphase? • 4 • 8 • 16 • 2 • 1
Sample Test Questions from Cell Cycle • During which phases of mitosis are chromosomes composed of two chromatids? • From G1 of interphase through metaphase • From interphase through anaphase • From anaphase through telophase • From metaphase through telophase • From G2 of interphase through metaphase
Hormones • Molecules secreted into extracellular fluid • Circulates through blood and hemolymph • Targets specific cells
2 Categories of Hormones • Figure 45.5 (pg. 978) • Water-soluble • Cannot pass through cell membrane • Lipid-soluble • Able to pass through the cell membrane
3 Groups of Hormones • Polypeptides • Ex: insulin • Water soluble • Amines • Ex: epinephrine, thyroxine • Water soluble • Steroids • Ex: cortisol • Lipid soluble
Water Soluble Hormones • Signal receptor on cell membrane • Typical activities of water soluble hormones • Activates enzymes • Alter uptake/secretion of molecules • Alter cytoskeleton
Water Soluble Hormones • Signal transduction: extracellular signal triggers a specific intracellular response • Example: epinephrine (Figure 45.6) • Secreted by adrenal gland • Reaches liver cells, causes breakdown of glycogen within the cell • Glucose is secreted into the blood stream
Lipid Soluble Hormones • Activities: • Causes a change in gene expression • Hormone and intracellular receptor bind • Complex moves into nucleus • Alter transcription
Negative Feedback of Hormones • Most hormones follow a negative feedback loop • Secretion of the hormone will cause a response which will reduce the stimulus which caused the secretion of the hormone
Antagonistic Hormones • Insulin and Glucagon • Both are produced in the pancreas • Endocrine cells called islets of Langerhans • Alpha cells – synthesis of glucagon • Beta cells – synthesis of insulin
Insulin and Glucagon • Insulin: • Released to increase uptake of glucose from the blood • Lowers blood sugar concentration • Glucagon: • Released to promote release of glucose into blood • Raises blood sugar concentration • Figure 45.12 pg. 983
Important Endocrine Glands (pg. 987) • Hypothalamus • Pituitary • Anterior Pituitary Gland • Posterior Pituitary Gland • Thyroid • Parathyroid • Adrenal • Gonads • Pineal
Hypothalamus • Integrates nervous system and endocrine system • Located within the brain • Initiates endocrine signaling in response to external stimuli • Seasonal changes • Mating
Pituitary Gland • At base of the hypothalamus • Anterior Pituitary – derivative of mouth during embryo development • Regulated by hypothalamus • Posterior Pituitary – extension of the hypothalamus • Stores and secretes hormones from hypothalamus
Posterior Pituitary Gland • Oxytocin • Positive feedback • Regulate milk production • Uterine contraction • Mood and sexual arousal • Antidiuretic hormone • Blood osmolarity • Kidney regulation • Increases water retention within the kidneys • Lowers volume of urine
Anterior Pituitary Gland • Hormone cascade pathways • Hormones triggering other hormones • Tropic hormones: regulates function of endocrine cells and glands • Nontropic hormones
Tropic Hormones • Follicle-stimulating hormone (FSH) • Lutenizing hormone (LH) • Both are produced in the gonads • Adenocorticotropic hormone (ACTH) • Steroid released from adrenal gland
Nontropic Hormones • Prolactin • Mammals: lactation • Birds: fat metabolism • Amphibians: delays metamorphosis • Thought to be conserved throughout evolution • Melanocyte stimulating hormone (MSH) • Skin pigmentation (amphibs, fish, reptiles) • Neurons in the brain (mammals)
Growth Hormone • Anterior pituitary gland • Targets liver • Releases insulin-like growth factors (IGFs) • Bone and cartilage growth • Hyper-release – gigantism • Hypo-release – dwarfism
Thyroid Hormone • Regulates: • Bioenergetics • Maintain normal: • Blood pressure • Heart rate • Muscle tone • Digestive and reproductive functions • 2 hormones: triiodonthyronine (T3), thyroxine (T4)
Thyroid Hormone • Hyperthyroidism • High body temperature • Excessive sweating • Weight loss • Irritability • High blood pressure • Hypothyroidism • Weight gain • Lethargy • Intolerance to cold • For proper thyroid function, need iodine (iodized salt)
Parathyroid Hormone • Regulates Ca2+ levels • Release of parathyroid hormone raises Ca2+ levels within the blood • Breakdown of bony matrix • Vitamin D – needed for proper Ca2+ absorption • Active form of Vit.D from kidneys triggers uptake of Ca2+ from food in intestines • Calcitonin – inhibits bone resorption(breakdown of bone to release calcium)
Adrenal Hormones • Adrenal glands • 2 parts: • Adrenal cortex • Adrenal medulla
Adrenal Hormones • Norepinephrine • Epinephrine • Both increase breakdown of glycogen in liver, skeletal muscles • Promote release of glucose by liver cells, fatty acids by fat cells • Increases heart rate, dilates bronchioles
Adrenal Hormones • Steroids from adrenal cortex • Corticosteroids: • Glucorticoids • Mineralcorticoids
Glucordicoids • Glucose metabolism from noncarbohydrate sources (skeletal muscles) • Cortisol – skeletal muscle breakdown • Glucose to liver and kidneys • Anti-inflammatory effect • NSAIDs have similar effect but without the negative side effects of steroids
Mineralocorticoids • Salt and water balance • Aldosterone • Stimulate kidney to balance water and sodium balance
Gonads • Female is “default” in mammals • Testosterone production triggers male development • Lower voice, increase muscle mass, bone mass • Testes produce androgens
Ovaries • Production of • Estrogens (estradol) • Female reproductive development • Secondary sex characteristics • Progestines (progesterone) • Uterine maintenance • Synthesis of androgens, estrogens, progestines – regulated by FSH, LH
Melatonin • Synthesis in the pineal gland • Near center of the brain in mammals • In lower vertebrates, has light receptors – closer to surface of body • Circadian rhythms, night/day