SAMPLE TEST QUESTIONS FROM CELL
CYCLE
1. If there are 20 chromatids in a cell, how many
centromeres are there?
a.
b.
c.
d.
e.
20
80
10
30
40
SAMPLE TEST QUESTIONS FROM CELL
CYCLE
1. If there are 20 chromatids in the cell at
metaphase, how many chromosomes are there in
each daughter cell following cytokinesis?
a.
b.
c.
d.
e.
80
10
30
20
40
SAMPLE TEST QUESTIONS FROM CELL
CYCLE
1. If a cell has 8 chromosomes at metaphase of
mitosis, how many chromosomes will it have
during anaphase?
a.
b.
c.
d.
e.
4
8
16
2
1
SAMPLE TEST QUESTIONS FROM CELL
CYCLE
• During which phases of mitosis are chromosomes
composed of two chromatids?
a.
b.
c.
d.
e.
From G1 of interphase through metaphase
From interphase through anaphase
From anaphase through telophase
From metaphase through telophase
From G2 of interphase through metaphase
CHAPTER 45: HORMONES
AND THE ENDOCRINE
SYSTEM
DAY 1
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
DAY 2
IMPORTANT ENDOCRINE GLANDS (PG.
987)
• Hypothalamus
• Pituitary
• Anterior Pituitary Gland
• Posterior Pituitary Gland
•
•
•
•
•
Thyroid
Parathyroid
Adrenal
Gonads
Pineal
HUMAN ENDOCRINE SYSTEM
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
DAY 3
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