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Flashcards in Biology Deck (103):
1

Prions

Infectious proteins - protein misfolding - alpha to beta reduces solubility

2

Viroids

Short ssRNA that infect plants - silence RNA genes - prevents synthesis of proteins

3

Viruses with envelopes vs without

Envelopes = easy to kill
No = difficult to kill

4

Virus replication

Can’t replicate independently because don’t have ribosomes

5

How do retroviruses synthesize DNA?

Reverse transcriptase

6

How is viral progeny released?

1. Apoptosis
2. Lysis
3. Fusion with pals a membrane

7

Classifications of bacteria (shape)

1. Cocci
2. Bacilli
3. Spirilla

8

Asexual reproduction of prokaryotes

Binary fission

9

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

10

Bacterial growth

Lag phase > exponential phase > stationary phase > death phase

11

Stages of Interphase

G1
S
G2

12

G1

Cells create fuel and increase in size
Also restriction point for S phase

13

S phase

Replicates genetic material - chromatids

14

G2

Twice as much DNA as G1
Another checkpoint

15

M phase

Prophase, metaphase, anaphase, and telophase

16

What molecules are responsible for cell cycle?

Cyklins > CDK > cyklin-CDK complex > (phosphate) > phosphorylated TFs > transcription

17

Where does mitosis occur?

Somatic cells or cells not involved in sexual reproduction

18

What types of cells do animals have? Germ cells?

Diploid
Haploid

19

Prophase

Chromatin > chromosomes
Spindles go to opposite poles

20

Metaphase

Kinetochores align chromosomes along metaphase plate

21

Anaphase

Centromeres split sister chromatids

22

Telophase and cytokinesis

Opposite of prophase - reappearance of nuclear membrane
Separation of daughter cells

23

Where does mitosis happen? Product?

Gametocytes (germ cells)
4 nonidentical gametes (sex cells)

24

Meiosis 1

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

25

Meiosis 2

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

26

How is biological sex determined?

23rd chromosome

27

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

28

How many sperm per spermatogenesis?

4

29

What does the mid piece of sperm contain and why?

Mitochondria for energy to swim

30

What hormones do the ovaries produce?

Estrogen and progesterone

31

Oogenesis

Production of female gametes

32

Where are primary oocytes suspended and until when? Secondary oocytes?

Prophase 1 until first menses
Metaphase 2 until fertilization

33

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

34

FSH and LH in males

FSH - sperm
LH - testosterone

35

FSH and LH in females

FSH - estrogen
LH - progesterone

36

What happens during female reproductive years?

Estrogen and progesterone levels rise and fall, which causes the endometrial lining to grow and shed

37

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

38

Blastulation

Morula forms blastula - hollow ball of cells

39

Gastrulation

Generation of 3 distinct cell layers

40

What does the archenteron form? Blastopore? Ectoderm? Mesoderm? Endoderm?

Gut
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

41

How does differentiation occur? How is it mediated?

Selective transcription
Inducers, is growth factors

42

Neurulation

Development of the nervous system

43

What does the notochord become? Neural tube? Neural crest cells?

Spine
Nervous system
Peripheral NS

44

Teratogens

Interfere with development

45

Potency of cells

Totipotent
Pluripotent
Multipotent

46

Morphogens

Cause differentiation of cells

47

Regeneration capacity
What do humans usually show?

Complete vs incomplete (humans)

48

Senescence

Biological aging

49

Astrocytes

Nourish neurons and form blood-brain barrier

50

Ependymal cells

Line ventricles of brain and produce cerebrospinal fluid

51

Microglia

Phagocytic cells in CNS

52

Oligodendrocytes (CNS) and Schwann cells (PNS)

Produce myelin around axons

53

What are the 4 divisions of the spinal cord?

Cervical, thoracic, lumbar, and sacral

54

Peptide hormones

Second messenger systems
Short lived
Rapid
Water soluble
Can’t pass membrane

55

Steroid hormones

Derived from cholesterol
Produced from gonads and adrenal cortex
Can pass membrane cause no polar
Not water soluble
(End in -one, -ol, -oid)

56

Amino acid derivative hormones

E and NE - fast, short lived
Thyroxine and triiodothyronine - longer, slower onset - regulate metabolic rate
(End in -in or -ine)

57

Direct vs tropic hormones

Don’t need intermediary
Need intermediary, ie GnRH

58

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)

59

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

60

What hormones are secreted by the posterior pituitary?

Oxytocin - contractions during labor and lactation
ADH - reabsorption of water in the kidneys

61

Direct hormones of the anterior pituitary

Prolactin - milk production
Endorphins - decrease affects of pain
Growth hormone

62

Two major functions of the thyroid

1. Setting basal metabolic rate - mediated by T3 and T4
2. Calcium homeostasis - mediated by calcitonin

63

Hypothyroidism

Iodine deficiency
Sx: lethargy, decreased body temp, slowed HR, and weigh gain

64

Hyperthyroidism

Excess of TSH
Sx: tumor, heightened activity, increased body temp, increased HR, and weight loss

65

Calcitonin

Tones down calcium levels by increased excretion by kidneys, decreased absorption by gut, and increased storage of calcium in bone

66

Parathyroid hormone (PTH)

Opposite of calcitonin
Activates vitamin D

67

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

68

Adrenal medulla hormones

E and NE

69

Pancreatic hormones

Glucagon - high when glucose is low - breakdown of fat and protein
Insulin - high when glucose is high
Somatostatin - inhibits glucagon and insulin

70

Pineal gland

Melatonin

71

Diaphragm

Under somatic control
Divides thoracic (chest) cavity

72

Inhalation

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

73

What prevents the collapse of alveoli? How?

Surfactant by reducing surface tension

74

Where is ventilation regulated? What neurons?

Medulla oblongata
Chemoreceptors - sensitive to CO2 lvls

75

Where does gas exchange occur?

Capillaries bring deoxygenated blood to pulmonary arteries (right), pulmonary veins carry oxygenated blood (left)

76

What is the driving force of gas exchange?

Pressure differential

77

How is heat regulated?

Vasodilation (thermal energy dissipated) and vasoconstriction (thermal energy conserved)

78

How to lungs fight off invaders?

Macrophages, antibodies, mast cells

79

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

80

What nerve slows down the heart?

Vagus nerve

81

Equation for cardiac output

CO = HR x SV

82

What does low BP and high BP release in relation to the CV system?

Low BP - aldosterone and ADH
High BP - ANP

83

How are clots broken down?

Plasmin

84

Antigen

RBC - surface proteins - target for immune system response (antibodies)

85

Rh factor

Antigens - The + or - part of blood types

86

What produces leukocytes

Bone marrow

87

B cells vs T cells

Part of the adaptive immune system

B - turn into plasma cells that later become antibodies
T - cell-mediated immunity

88

What do leukocytes become?

Granulocytes
Agranulocytes

89

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

90

Interferons

Defense against viruses - decrease protein production

91

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

92

Natural Killer Cells

Recognize the Dow regulation of MHC by pathogens avoiding immune response and cause apoptosis of affected cell

93

Mast cells

Release histamine and other chemicals to promote inflammation

94

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

95

What connects the heavy and light chains of antibodies?

Disulfide bond

96

Duodenum

Chemical digestion with some absorption

97

Where is bike created?

Liver

98

Colon

Absorbs water and salt

99

What accounts for the concentration of urine

Collecting duct

100

Where does most reabsorption in the excretory system occur

Proximal convoluted tubule

101

Missense vs nonsense mutations

Missense - changes AA
Nonsense - changes to stop codon

102

Genetic drift

More pronounce in small populations - changes to gene pool

103

Founder effect

Small population in reproductive isolation
- inbreeding may occur