Biology Flashcards
1
Q
Nucleus
A
Contains all of the genetic material necessary for replication of the cell
2
Q
Mitochondrion
A
Location of many metabolic processes (pyruvate dehydrogenase, CAC, ETC, oxidative phosphorylation, β-oxidation, some of gluconeogenesis, urea cycle) and ATP production
3
Q
Lysosomes
A
Membrane-bound structures containing hydrolytic enzymes capable of breaking down many different substrates
4
Q
Rough ER
A
Interconnected membranous structure with ribosomes studding the outside; site of synthesis for proteins destined for insertion into a membrane or secretion
5
Q
Smooth ER
A
Interconnected membranous structure where lipid synthesis and detoxification occurs
6
Q
Golgi apparatus
A
Membrane-bound sacs where posttranslational modification of proteins occurs
7
Q
Peroxisomes
A
Organelle containing hydrogen peroxide; site of β-oxidation of very long chain fatty acids
8
Q
Fluid mosaic model and membrane traffic
A
Phospholipid bilayer with cholesterol and embedded proteins
Exterior: hydrophilic phosphate head groups
Interior: hydrophobic fatty acids
9
Q
Cell theory
A
All living things are composed of cells; the cell is the basic functional unit of life; cells arise only from preexisting cells
A fourth tenet has been added: cells carry genetic information in the form of DNA
10
Q
Eukaryotes
A
Contain membrane-bound organelles such as a nucleus, while prokaryotes are simpler cells without a nucleus
11
Q
Prokaryotes
A
All divide by binary fission; circular chromosome replicates and attaches to the cell wall; the plasma membrane and cell wall grow along the midline, forming daughter cells
12
Q
Flagella
A
Eukaryotes: contain a basal body that serves as the engine for motion
13
Q
Gram-positive
A
Have large quantities of peptidoglycan in the cell wall
14
Q
Gram-negative
A
Have much smaller quantities of peptidoglycan with lipopolysaccharides
15
Q
Shapes of bacteria
A
Cocci: spherical
Bacilli: rod-shaped
Spirilli: spiral-shaped
16
Q
Cell division
A
G1: cell increases its organelles and cytoplasm
S: DNA replication
G2: same as G1
M: the cell divides in two
Mitosis: PMAT
Meiosis: PMAT X 2
17
Q
Meiosis I
A
- Two pairs of sister chromatids form tetrads during prophase I
- Crossing over leads to genetic recombination in prophase I
- Homologous chromosomes separate during metaphase I
18
Q
Meiosis II
A
- Essentially identical to mitosis, but no replication
- Meiosis occurs in spermatogenesis (sperm formation) and oogenesis (egg formation)
19
Q
Four stages of early development
A
- Cleavage: mitotic divisions
- Implantation: embryo implants during blastula stage
- Gastrulation: ectoderm, endoderm, and mesoderm
- Neurulation: germ layers develop a nervous system
20
Q
Ectoderm
A
“attract”oderm
- NS, epidermis, lens of eye, inner ear
21
Q
Endoderm
A
“endernal” organs
- Lining of digestive tract, lungs, liver, and pancreas
22
Q
Mesoderm
A
“means”oderm
- Muscles, skeleton, circulatory system, gonads, kidney
23
Q
The liver’s role in homeostasis
A
- Gluconeogenesis
- Processing of nitrogenous wastes (urea)
- Detoxification of wastes/chemicals/drugs
- Storage of iron and vitamin A
- Synthesis of bile and blood proteins
- β-oxidation of fatty acids to ketones
- Interconversion of carbohydrates, fats, and AA
24
Q
Layers of the skin
A
Stratum corneum, statum lucidum, stratum granulosum, stratum spinosum, stratum basalis
25
Osmoregulation
- Filtration at the glomerulus; filtrate (fluid and small solutes) passes through *passive*
- Secretion of acids, bases, and ions from interstitial fluid to filtrate; maintains pH, [K+] and [waste] *passive and active*
- Reabsorption: essential substances and water flow from filtrate to blood; enabled by osmolarity gradient and selective permeability of the walls *passive and active*
26
Aldosterone
Stimulates Na+ and water reabsorption
- Secreted from adrenal cortex in response to low blood pressure
- Regulated by the renin-angiotensin-aldosterone system
27
ADH (vasopressin)
Increases collecting duct's permeability to water to increase water reabsorption
- Released from the posterior pituitary in response to high blood osmolarity
28
Four stages of the menstrual cycle
1. Follicular: FSH causes growth of a follicle
2. Ovulation: LH causes follicle to release egg
3. Luteal: corpus luteum forms
4. Menstruation: endometrial lining sheds
29
Mechanisms of hormone action
Peptides act via second messengers and steroids act via hormone/receptor binding to DNA; AA-derivative hormones may do either
30
Resting potential
- Na+/K+ ATPase creates gradient of high [Na+] outside the cell, and high [K+] inside
- Movement of ions down their concentration gradient through leak channels establishes resting potential
31
Action potential
- Stimulus acts on the neuron, depolarizing the membrane of the cell body
32
Impulse propagation
Depolarization (Na+ rushing into axon) followed by repolarization (K+ rushing out of axon) along the nerve axon
33
The synapse
- At the synaptic knob, voltage-gated Ca2+ channels open, sending Ca2+ into the cell
- Vesicles fuse with presynaptic membrane sending the neurotransmitter across the synaptic cleft
- Neurotransmitter binds to receptors on the postsynaptic membrane, triggering depolarization
34
Gates in action potential
I: Rest - all gates closed
II: Depolarization - Na+ gates open
III: Repolarization - Na+ gates inactive; K+ gates open
IV: Hyperpolarization - all gates closed
35
NS Flowchart
NS
Central: brain and spinal cord
Peripheral: sensory and motor - somatic and automatic - parasympathetic and sympathetic
36
Follicle-stimulating (FSH)
Source: anterior pituitary
Action: stimulates follicle maturation; spermatogenesis
37
Luteinizing (LH)
Source: anterior pituitary
Action: stimulates ovulation; testosterone synthesis
38
Adrenocorticotropic (ACTH)
Source: anterior pituitary
Action: stimulates adrenal cortex to make and secrete glucocorticoids
39
Thyroid-stimulating (TSH)
Source: anterior pituitary
Action: stimulates the thyroid to produce thyroid hormones
40
Prolactin
Source: anterior pituitary
Action: stimulates milk production and secretion
41
Endorphins
Source: anterior pituitary
Action: inhibits the perception of pain the brain
42
Growth hormone
Source: anterior pituitary
Action: stimulates bone and muscle growth/lipolysis
43
Oxytocin
Source: hypothalamus; stored in posterior pituitary
Action: stimulates uterine contractions during labor, milk secretion during lactation
44
Antidiuretic (ADH, vasopressin)
Source: hypothalamus; stored in posterior pituitary
Action: stimulates water reabsorption in kidneys
45
Thyroid hormones (T3, T4)
Source: thyroid
Action: stimulates metabolic activity
46
Calcitonin
Source: thyroid
Action: decreases (tones down) blood calcium level
47
Parathyroid hormone
Source: parathyroid
Action: increases blood calcium level
48
Glucocorticoids
Source: adrenal cortex
Action: increases blood glucose level and decreases protein synthesis; anti-inflammatory
49
Mineralocorticoids
Source: adrenal cortex
Action: increases sodium and water reabsorption in kidneys
50
Epinephrine, norepinephrine
Source: adrenal medulla
Action: increases blood glucose level and heart rate
51
Glucagon
Source: pancreas
Action: stimulates conversion of glucogen to glucose in the liver; increases blood glucose
52
Insulin
Source: pancreas
Action: lowers blood glucose; increases glycogen stores
53
Somatostatin
Source: pancreas
Action: suppresses secretion of glucagon and insulin
54
Testosterone
Source: testes
Action: maintains male secondary sex characteristics
55
Estrogen
Source: ovary/placenta
Action: maintains female secondary sex characteristics
56
Progesterone
Source: ovary/placenta
Action: promotes growth/maintenance of endometrium
57
Melatonin
Source: pineal
Action: regulates sleep-wake cycles
58
Atrial natriuretic peptide
Source: heart
Action: involved in osmoregulation and vasodilation
59
Thymosin
Source: thymus
Action: stimulates T-cell development
60
Sarcomere
- Contractile unit of the fibers in skeletal muscle
- Contains thin actin and thick myosin filaments
61
Initiation
Depolarization of a neuron leads to an action potential
62
Sarcomere shortening
- Sarcoplasmic reticulum releases Ca2+
- Ca2+ binds to troponin on the actin filament
- Tropomyosin shifts, exposing myosin-binding sites
- Myosin binds, ATPase activity allows myosin to pull thin filaments towards the center of the H zone, and then ATP causes dissociation
63
Relaxation
Ca2+ is pumped back into the sarcoplasmic reticulum
64
Bone formation and remodeling
- Osteoblast: builds bone
- Osteoclast: breaks down bone
- Reformation: inorganic ions are absorbed from the blood for use in bone
- Degradation (resorption): inorganic ions are released into the blood
65
Circulatory pathway through the heart
Super and inferior vena cava - right atrium - right ventricle - pulmonary arteries - lungs - pulmonary veins - left atrium - left ventricle - aorta - body
66
Three portal systems:
Blood travels through an extra capillary bed before returning to the heart
- Liver (hepatic), kidney, and brain (hypophyseal)
67
Fetal circulation
- Foramen ovale: connects right and left atria
- Ductus arteriosus: connects pulmonary artery to aorta; along with foramen ovale, shunts blood away from lungs
- Ductus venosus: connects umbilical vein to inferior vena cava, connecting umbilical circulation to central circulation
68
Plasma
Aqueous mixture of nutrients, wastes, hormones, blood proteins, gases, and salts
69
Erythrocytes (RBCs)
Carry oxygen
- Hemoglobin: four subunit carry O2 and CO2; iron controls binding and releasing
- Oxygen-hemoglobin dissociation: right shift of curve - increase temp, Bohr effect, decrease pH, increase pCO2, O2 release to tissues enhanced when H+ allosterically binds to Hb, increase pCO2 leads to increase [H+]
70
Leukocytes (WBCs)
Function in immunity
71
Platelets
Clotting
- Platelets release thromboplastin, which (along with cofactors Ca and vitamin K) converts inactive prothrombin to active thrombin
- Thrombin converts fibrinogen into fibrin, which surrounds blood cells to form the clot
72
Blood typing and Rh
- Blood cells with Rh factor are Rh+; these individuals produce no anti-Rh antibody.
- Rh- blood cells lack the antigen; these individuals produce an antibody if exposed
- If type A: antigen A, antibodies (anti-B)
73
Gas exchange
- Exchange occurs across the thin walls of alveoli
- Deoxygenated blood enters the pulmonary capillaries that surround the alveoli
- O2 from the inhaled air diffuses down its gradient into the capillaries, where it binds with hemoglobin and returns to the heart
- CO2 from the tissues diffuses from the capillaries to the alveoli, and is exhaled
74
Fetal respiration
- Fetal hemoglobin has a higher affinity for oxygen than adult hemoglobin
- Gas and nutrient exchanges occur across the placenta
75
Lipid digestion
- When chyme is present, the duodenum secretes the hormone cholecystokinin (CCK) into the blood
- CCK stimulates the secretion of pancreatic enzymes and bile and promotes satiety
- Bile is made in the liver and emulsifies fat in the small intestine; it's not an enzyme
- Lipase is an enzyme made in the pancreas that hydrolyzes lipids in the small intestine
76
Salivary amylase (ptyalin)
Production site: salivary glands
Function site: mouth
Hydrolysis rxn: starch --> maltose
77
Pancreatic amylase
Production site: pancreas
Function site: sm intestine
Hydrolysis rxn: starch --> maltose
78
Maltase
Production site: intestinal glands
Function site: sm intestine
Hydrolysis rxn: maltose --> 2 glucoses
79
Sucrase
Production site: intestinal glands
Function site: sm intestine
Hydrolysis rxn: sucrose --> glucose, fructose
80
Lactase
Production site: intestinal glands
Function site: sm intestine
Hydrolysis rxn: lactose --> glucose, galactose
81
Pepsin
Production site: gastric glands (chief cells)
Function site: stomach
Function: hydrolyzes specific peptide bonds
82
Trypsin
Production site: pancreas
Function site: sm intestine
Function: hydrolyzes specific peptide bonds; converts chymotrypsinogen to chymotrypsin
83
Chymotrypsin
Production site: pancreas
Function site: sm intestine
Function: hydrolyses specific peptide bonds
84
Carboxypeptidases A and B
Production site: pancreas
Function site: sm intestine
Function: hydrolyzes terminal peptide bond at C-terminus
85
Aminopeptidase
Production site: intestinal glands
Function site: sm intestine
Function: hydrolyzes terminal peptide bond at N-terminus
86
Dipeptidases
Production site: intestinal glands
Function site: sm intestine
Function: hydrolyzes part of AAs
87
Enteropeptidase
Production site: intestinal glands
Function site: sm intestine
Function: converts trypsinogen and procarboxypeptidases to active form
88
Memory cells
(B-lymphocyte)
- Remember antigen, speed up secondary response
89
Plasma cells
(B-lymphocyte)
- Make and release antibodies (IgG, IgA, IgM, IgD, and IgE) which induce antigen phagosytosis
90
Active immunity
Antibodies are produced during an immune response
91
Passive immunity
Antibodies produced by one organism are transferred to another organism
92
Cytotoxic T-cells
(T-lymphocytes)
- Destroy cells directly
93
Helper T-cells
(T-lymphocytes)
- Activate B- and T-cells and macrophages by secreting lymphokines
94
Suppressor T-cells
(T-lymphocytes)
- Regulate B- and T-cells to decrease anti-antigen activity
95
Memory cells
Also T-lymphocytes
96
Nonspecific immune response
Includes skin, passages lined with cilia, macrophages, inflammatory response, and interferons (proteins that help prevent the spread of a virus)
97
Lympathic system
- Lymph vessels meet at the thoracic duct in the upper chest and neck, draining into the left subclavian vein of the cardiovascular system
- Vessels carry lymph (excess interstitial fluid), and lacteals collect fats by absorbing chylomicrons in the sm. intestine
- Lymph nodes are swellings along the vessels with phagocytic cells (macrophages); they remove foreign particles from lymph
98
Law of segregation
Homologous alleles (chromosomes) separate so that each gamete has one copy of each gene
- If both parents are Rr, the alleles separate to give a genotypic ration of 1:2:1 and a phenotypic ration of 3:1
99
Law of independent assortment
Alleles of unlinked genes assort independently in meiosis
- For two traits: AaBb parents will produce AB, Ab, aB, and ab gametes
- The phenotypic ratio for this cross is 9:3:3:1
100
Genetic mapping
- Crossing over during meiosis I can unlink genes (prophase I)
- Genes are most likely unlinked when far apart
- One map unit is 1% recombinant frequency
101
Autosomal recessive
May skip generations
102
Autosomal dominant
Appears in every generation
103
X-linked (sex-linked)
No male-to-male transmission, and more males are affected
104
Hardy-Weinberg equilibrium
No mutations, large population, random mating, no migration, and equal reproductive success
p + q = 1; p^2 + 2pq + q^2 = 1
p: dominant allele
q: recessive allele
p^2: dominant homozygotes
2pq = heterozygotes
q^2: recessive homozygotes
105
Nucleic acids
Basic unit: nucleotide (sugar, nitrogenous base, phosphate)
- 2 types of bases: double-ringed purines (adenine, guanine) and single-ringed pyrimidines (cytosine, uracil, and thymine)
- A = T, C (triple)G
106
Structural genes
Have DNA that codes for protein
107
Operator gene
Repressor binding site
108
Promoter gene
RNA polymerase's 1st binding site
109
Inducible systems
Need an inducer for transcription to occur
110
Repressible systems
Need a corepressor to inhibit transcription
111
Point mutation
One nucleotide is substituted by another; they are silent if the sequence of AA doesn't change
112
Frameshift
Insertions or deletions shift reading frame; protein doesn't form, or is nonfunctional
113
Viruses
Acellular structures of double- or single-stranded DNA or RNA in a protein coat
114
Lytic cycle
Virus kills the host cell
115
Lysogenic cycle
Virus enters the host genome
116
Plasmids
Extragenomic material; they can be integrated into the genome, but are then called episomes
117
Transformation
Occurs when a bacterium acquires a piece of genetic material from the environment and integrates that piece of genetic material into the host cell genome. This is a common method by which antibiotic resistance can be acquired
118
Conjugation
Bacterial form of mating (sexual reproduction)
- 2 cells forming a cytoplasmic bridge allowing for transfer of genetic material; transfer is from donor male (+) to recipient female (-)
- Bridge is made of sex pili; to form the pilus, bacteria must contain plasmids known as sex factors
119
Transduction
Occurs when a bacteriophage acquires genetic information from a host cell. Sometimes, when the new virions are assembled in a host cell is packaged along with the viral genetic material.
- Then, the bacteriophage infects another bacterium, resulting in transfer of bacterial genetic material
