Flashcards in Biology Deck (103):
Infectious proteins - protein misfolding - alpha to beta reduces solubility
Short ssRNA that infect plants - silence RNA genes - prevents synthesis of proteins
Viruses with envelopes vs without
Envelopes = easy to kill
No = difficult to kill
Can’t replicate independently because don’t have ribosomes
How do retroviruses synthesize DNA?
How is viral progeny released?
3. Fusion with pals a membrane
Classifications of bacteria (shape)
Asexual reproduction of prokaryotes
Bacterial genetic recombination
1. Transformation - foreign DNA in host genome
2. Conjugation - bacterial form of mating
3. Transduction - requires a host, ie bacteriophage
4. Transposons - capable of inserting and removing themselves
Lag phase > exponential phase > stationary phase > death phase
Stages of Interphase
Cells create fuel and increase in size
Also restriction point for S phase
Replicates genetic material - chromatids
Twice as much DNA as G1
Prophase, metaphase, anaphase, and telophase
What molecules are responsible for cell cycle?
Cyklins > CDK > cyklin-CDK complex > (phosphate) > phosphorylated TFs > transcription
Where does mitosis occur?
Somatic cells or cells not involved in sexual reproduction
What types of cells do animals have? Germ cells?
Chromatin > chromosomes
Spindles go to opposite poles
Kinetochores align chromosomes along metaphase plate
Centromeres split sister chromatids
Telophase and cytokinesis
Opposite of prophase - reappearance of nuclear membrane
Separation of daughter cells
Where does mitosis happen? Product?
Gametocytes (germ cells)
4 nonidentical gametes (sex cells)
Prophase 1 - 2 homologous chromosomes > tetrad connected at chiasma > crossing over > recombinant chromosomes
Metaphase 1 - metaphase plate alignment of tetrads
Anaphase 1 - chromosomes separated from tetrad - disjunction
Telophase 1 - 2 haploid cells with one homologous chromosome
Prophase 2 - nuclear envelope disappears, nucleoli disappear, centrioles migrate
Metaphase 2 - metaphase plate
Anaphase 2 - split into sister chromatids
Telophase 2 - 4 haploid daughter cells
How is biological sex determined?
Sex linked is X linked
Men will most likely display sex linked disorders while females can be heterozygous or homozygous cause they have 2 Xs
How many sperm per spermatogenesis?
What does the mid piece of sperm contain and why?
Mitochondria for energy to swim
What hormones do the ovaries produce?
Estrogen and progesterone
Production of female gametes
Where are primary oocytes suspended and until when? Secondary oocytes?
Prophase 1 until first menses
Metaphase 2 until fertilization
How is sexual development restricted before puberty?
Hypothalamus is prevented from producing GnRH, but once produced will activate anterior pituitary that produces FSH and LH
FSH and LH in males
FSH - sperm
LH - testosterone
FSH and LH in females
FSH - estrogen
LH - progesterone
What happens during female reproductive years?
Estrogen and progesterone levels rise and fall, which causes the endometrial lining to grow and shed
Stages of the mistrial cycle
1. Follicular - low FSH and LH stimulate increase GnRH increasing these, develop follicles, produce estrogen, negative feedback on hormones
2. Ovulation - estrogen causes flux in hormones, but increased LH causes ovulation
3. Luteal - increased LH so increased progesterone
4. Menstruation - decrease estrogen and progesterone
5. Pregnancy - increased hCG
6. Menopause - no longer sensitive to FSH and LH
Morula forms blastula - hollow ball of cells
Generation of 3 distinct cell layers
What does the archenteron form? Blastopore? Ectoderm? Mesoderm? Endoderm?
Anus (human) or mouth
External layer: Epidermis, hair, nails, epithelia, nervous system, adrenal medulla, pituitary gland
Middle layer: Musculoskeletal, circulatory, and excretory systems, adrenal cortex
Internal layer: Epithelial linings of tracts, pancreas, liver, thyroid, lung, bladder, urethra
How does differentiation occur? How is it mediated?
Inducers, is growth factors
Development of the nervous system
What does the notochord become? Neural tube? Neural crest cells?
Interfere with development
Potency of cells
Cause differentiation of cells
What do humans usually show?
Complete vs incomplete (humans)
Nourish neurons and form blood-brain barrier
Line ventricles of brain and produce cerebrospinal fluid
Phagocytic cells in CNS
Oligodendrocytes (CNS) and Schwann cells (PNS)
Produce myelin around axons
What are the 4 divisions of the spinal cord?
Cervical, thoracic, lumbar, and sacral
Second messenger systems
Can’t pass membrane
Derived from cholesterol
Produced from gonads and adrenal cortex
Can pass membrane cause no polar
Not water soluble
(End in -one, -ol, -oid)
Amino acid derivative hormones
E and NE - fast, short lived
Thyroxine and triiodothyronine - longer, slower onset - regulate metabolic rate
(End in -in or -ine)
Direct vs tropic hormones
Don’t need intermediary
Need intermediary, ie GnRH
Tropic hormones of the hypothalamus to anterior pituitary
GnRH > FSH, LH
Growth hormone releasing hormone (GHRH) > growth hormone (GH)
Thyroid releasing hormone (TRH) > thyroid stimulating hormone (TSH)
Corticotropin releasing factor (CRF) > adrenocorticotropic hormone (ACTH)
How is cortisol activated and mediated?
ACTH stimulates the adrenal cortex to produce cortisol, but cortisol will have a negative feedback effect on the anterior pituitary and hypothalamus
What hormones are secreted by the posterior pituitary?
Oxytocin - contractions during labor and lactation
ADH - reabsorption of water in the kidneys
Direct hormones of the anterior pituitary
Prolactin - milk production
Endorphins - decrease affects of pain
Two major functions of the thyroid
1. Setting basal metabolic rate - mediated by T3 and T4
2. Calcium homeostasis - mediated by calcitonin
Sx: lethargy, decreased body temp, slowed HR, and weigh gain
Excess of TSH
Sx: tumor, heightened activity, increased body temp, increased HR, and weight loss
Tones down calcium levels by increased excretion by kidneys, decreased absorption by gut, and increased storage of calcium in bone
Parathyroid hormone (PTH)
Opposite of calcitonin
Activates vitamin D
Adrenal cortex hormones
Glucocorticoids - cortisol and cortisone - increase blood glucose - under control of ACTH
Mineralocorticoids - aldosterone - water and sodium reabsorption - controlled by renin
Cortical sex hormones - androgens and estrogens
Adrenal medulla hormones
E and NE
Glucagon - high when glucose is low - breakdown of fat and protein
Insulin - high when glucose is high
Somatostatin - inhibits glucagon and insulin
Under somatic control
Divides thoracic (chest) cavity
Diaphragm flattens, chest wall expands and pulls lungs
Volume increases so pressure decreases -> results in negative pressure breathing because atmospheric pressure (outside) is now higher
What prevents the collapse of alveoli? How?
Surfactant by reducing surface tension
Where is ventilation regulated? What neurons?
Chemoreceptors - sensitive to CO2 lvls
Where does gas exchange occur?
Capillaries bring deoxygenated blood to pulmonary arteries (right), pulmonary veins carry oxygenated blood (left)
What is the driving force of gas exchange?
How is heat regulated?
Vasodilation (thermal energy dissipated) and vasoconstriction (thermal energy conserved)
How to lungs fight off invaders?
Macrophages, antibodies, mast cells
How do the lungs control pH?
Bicarbonate buffer system
- increased H+ will increase CO2, increasing respiratory rate
- decreased H+ will decrease CO2, decreasing respiratory rate
What nerve slows down the heart?
Equation for cardiac output
CO = HR x SV
What does low BP and high BP release in relation to the CV system?
Low BP - aldosterone and ADH
High BP - ANP
How are clots broken down?
RBC - surface proteins - target for immune system response (antibodies)
Antigens - The + or - part of blood types
What produces leukocytes
B cells vs T cells
Part of the adaptive immune system
B - turn into plasma cells that later become antibodies
T - cell-mediated immunity
What do leukocytes become?
What is the complement system?
Proteins in the blood that act in a nonspecific defense to bacteria - punches hole in bacteria to make it osmotically unstable
-classical - antibody to pathogen
-alternative - no antibody
Defense against viruses - decrease protein production
MHC class 1
MHC class 2
Present pathogens to the adaptive immune system
1 - endogenous pathway - present antigen from inside
2 - exogenous pathway - present antigen from outside
Natural Killer Cells
Recognize the Dow regulation of MHC by pathogens avoiding immune response and cause apoptosis of affected cell
Release histamine and other chemicals to promote inflammation
What are the 3 responses of antibodies?
1. Opsonization - attract more leukocytes to attack antigen
2. Agglutinate - cause pathogen to clump together
3. Prevent pathogen from entering tissue
What connects the heavy and light chains of antibodies?
Chemical digestion with some absorption
Where is bike created?
Absorbs water and salt
What accounts for the concentration of urine
Where does most reabsorption in the excretory system occur
Proximal convoluted tubule
Missense vs nonsense mutations
Missense - changes AA
Nonsense - changes to stop codon
More pronounce in small populations - changes to gene pool