Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

MCAT Bio > Bio #3 > Flashcards

Bio #3 Flashcards

You may prefer our related Brainscape-certified flashcards:
MCAT flashcards Biology 101 flashcards
1
Q

all embryos are ____ by default but then the ______ gene produces ______. This occurs around _____ post-fertilization.

A

female
SRY
masculinization
6-8 weeks post-fertilization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

fertilization

A

Occurs in the widest part of the fallopian tube called the ampulla.
o Sperm releases acrosomal enzymes that allow it to get through the corona radiata and the zona pellucida.
o First sperm to come in contact with the secondary oocyte’s cell membrane forms a tube-like acrosomal apparatus which extends and penetrates the cell membrane.
 Sperm pronucleus then enters the oocyte after meiosis II
o Cortical reaction: release of calcium ions after the sperm penetrates the cell membrane.
 The depolarization that occurs does not allow the egg to be fertilized by another sperm cell and it increases the metabolic rate of the newly formed zygote.
 Fertilization membrane: depolarized and impenetrable membrane.
o Twins
 Dizygotic (fraternal) twins: fertilization of two different eggs released during one ovulatory cycle by two different sperm.
• Each develops own placenta, chorion, and amnion.
 Monozygotic (identical) twins: when a single zygote splits into two.
• Conjoined twins: result of incomplete division, two offspring are physically attached.
• Specific label depends on when they split.
• The more shared gestational structures the more risks are apparent as the fetus grows.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what are the steps of embryogenesis

A
  1. fertilization
  2. cleavage
  3. blastulation
  4. gastrulation
  5. differentiation
  6. neurulation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

where does fertilization occur?

A

Occurs in the widest part of the fallopian tube called the ampulla.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

sperm releases _______ that allow it to get through the corona radiata and the zona pellucida.

A

acrosomal enzymes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

First sperm to come in contact with the secondary oocyte’s cell membrane forms a tube-like _____ which extends and penetrates the cell membrane.
The sperm pronucleus then enters the oocyte after ______ is complete.

A

acrosomal apparatus

meiosis II

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

cortical reaction

A

release of calcium ions after the sperm penetrates the cell membrane.
 The depolarization that occurs does not allow the egg to be fertilized by another sperm cell and it increases the metabolic rate of the newly formed zygote.
 Fertilization membrane: depolarized and impenetrable membrane.

The calcium ions are held in cortical granules right inside of the secondary oocyte/mature ovum.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

dizygotic twins

A

(fraternal) twins: fertilization of two different eggs released during one ovulatory cycle by two different sperm.
• Each develops own placenta, chorion, and amnion.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

monozygotic twins

A

(identical) twins: when a single zygote splits into two.

characterized by what structures they share (chorion or amnion).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

conjoined twins

A

result of incomplete division, two offspring are physically attached.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

the _____ has the greatest nucleus to cytoplasm ratio

A

blastula

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

neural tube is _______ and the notocord is ______

A

ectodermal

mesodermal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

need ____ to make adult stem cells pluripotent

A

transcription factors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

imperforate anus is formed when there is not proper _______ in the digestive tract

A

apoptosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

_____ in the fetus are very sensitive and mature very late

A

lung tissues

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

cleavage

A

step 1
o Cleavage: the zygote undergoes rapid mitotic cell divisions.
 Indeterminate cleavage: cells that can still develop complete organisms or any cell type.
 Determinate cleavage: results in cells with fates that are already determined. They are committed to differentiating into a certain cell type. One path.
o Zygote must get to uterus in time so there is an endometrium still capable of supporting the embryo.
o First cleavage creates unicellularity.
o Divisions into smaller cells gives: increase the nuclear to cytoplasmic ration and the surface area to volume ratio (increased area for gas and nutrient exchange).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

cleavage

A

step 2
o Cleavage: the zygote undergoes rapid mitotic cell divisions.
 Indeterminate cleavage: cells that can still develop complete organisms or any cell type.
 Determinate cleavage: results in cells with fates that are already determined. They are committed to differentiating into a certain cell type. One path.
o Zygote must get to uterus in time so there is an endometrium still capable of supporting the embryo.
o First cleavage creates unicellularity.
o Divisions into smaller cells gives: increase the nuclear to cytoplasmic ration and the surface area to volume ratio (increased area for gas and nutrient exchange).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

indeterminate cleavage

A

cells that can still develop complete organisms or any cell type.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

determinate cleavage

A

results in cells with fates that are already determined. They are committed to differentiating into a certain cell type. One path.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

cleavage allows for _____

A

o Divisions into smaller cells gives: increase the nuclear to cytoplasmic ration and the surface area to volume ratio (increased area for gas and nutrient exchange).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

blastulation

A

step 3
morula ==> blastocyst ==> implantation

 Blastula moves to uterus and burrows into the endometrium.
 Trophoblasts connect the embryo to the maternal blood supply.
• Trophoblasts give rise to the chorion: an extraembryonic membrane that develops into the placenta.
• Trophoblasts form chorionic villi: microscopic fingerlike projections that penetrate the endometrium.
o Support maternal-fetal gas exchange

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

umbilical cord

A

connects the embryo to the placenta, consists of two arteries and one vein encased in gelatinous substance.
• Vein: oxygenated blood
• Arteries: deoxygenated blood and waste to placenta.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

yolk sac

A

the site of early blood development that supports the embryo until the placenta is functional.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

allantois

A

involved in early fluid exchange between the embryo and the yolk sac
o Umbilical cord is formed from allantois and yolk sac

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

amnion

A

surrounds the allantois, thin, tough membrane filled with amniotic fluid.
o Shock absorber during pregnancy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

chorion

A

develops into the placenta

forms another outer layer around the amnion.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

the umbilical cord is formed from the _____

A

allantois and yolk sac

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

gastrulation

A

step 4
after the cell mass implants, can begin more developmental processes such as the generation of three distinct cell layers.

o Gastrula: results after invagination, poke finger into balloon and then the outer membrane comes together.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

archenteron

A

the membrane invagination into the blastocoel, later develops into the gut.
 Blastopore: opening of the archenteron
• Deuterostomes: the blastopore is the anus
• Protostomes: the blastopore is the mouth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

what are the primary germ layers

A

ectoderm
mesoderm
endoderm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

what does the ectoderm give rise to?

A

outermost layer
• Gives rise to the integument: epidermis, hair, nails, epithelia of nose, mouth, and lower anal canal. Lens of the eye, nervous system (adrenal medula too) and inner ear.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

what does the mesoderm give rise to?

A

the middle layer
Means of gettering around: bones and muscle, sleeping around, around the body circulatory system
• Gives rise to the musculoskeletal, circulatory, and most of the excretory systems. Gives rise to the gonads, muscular and connective tissue layers of the digestive and respiratory systems and the adrenal cortex.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

what does the endoderm give rise to?

A

innermost layers
Linings of endernal, digestive and respiratory tract
• Gives rise to the epithelial linings of the digestive and respiratory tracts, including the lungs.
• Also the pancreas, thyroid, bladder, distal urinary tracts, and parts of the liver.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

differentiation

A

step 5
o Selective transcription: of the genome allows it, certain genes are turned on
o Induction: the ability of one group of cells to influence the fate of nearby cells.
 Inducers: chemical substances that diffuse from organizing cells to responsive cells.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

induction

A

the ability of one group of cells to influence the fate of nearby cells.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

inducers

A

chemical substances that diffuse from organizing cells to responsive cells that influence the fate of responsive cells.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

neurulation

A

step 6
o Neurulation: development of the nervous system, after the 3 germ layers are established.
o First the notochord forms from mesoderm cells.
o The notochord induces ectodermal cells to slide inward to form neural folds, which surround a neural groove.
o Neural folds grow toward one another to form the neural tube, gives rise to the central nervous system.
o Neural crest cells: at the tip of each neural groove.
 Migrate to form the peripheral NS (sensory ganglia, autonomic ganglia, adrenal medulla, and Schwann cells) and other stuff (melanocytes in skin)
o Ectodermal cells migrate over the neural tube and crest to cover the rudimentary NS.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

the _____ induces ectodermal cells to slide inward to form ______ and eventually the ______

A

notochord
neural folds
neural tube

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

neural crest cells and what they become

A

at the tip of each neural groove.
 Migrate to form the peripheral NS (sensory ganglia, autonomic ganglia, adrenal medulla, and Schwann cells) and other stuff (calcitonin producing cells of the thyroid, melanocytes in skin)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

teratogens

A

substances that interfere with development, causing defects or even death of the developing embryo.
 Ex: alcohol, drugs, viruses, bacteria, and environmental chemical
 Overall effects depend on genetics of fetus and exposure levels.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

cell specialization

A

o In order to create an organism as complex as the human, each cell must perform a specialized function and the cells must be organized so that the organ can function properly.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

specification

A

the cell is reversibly designated as a specific cell type

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

determination

A

the commitment of a cell to a particular function in the future. Irreversibly committed to a specific cell lineage. Happens in a couple ways:
• Unequal distribution of existing mRNA and protein during cleavage
• Secretion of morphogens (molecules) from nearby cells.
• Commitment to particular cell type, but the cell has not produced what it needs to to carry out the function of that cell type yet.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

differentiation

A

changing the cell’s structure, function, and biochemistry to match the cell type it has been determined to be.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

stem cells

A

cells that have not yet differentiated or that give rise to other cells that will differentiate.

they exist in both embryonic and adult tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

potency

A

determines the types of tissues a particular stem cell can differentiate into.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

totipotent

A

have the greatest potency, can differentiate into any cell type either in the fetus or the placental structures.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

pluripotent

A

cells can differentiate into any cell type except for those found in the placental structures.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

multipotent

A

cells that can differentiate into multiple cells types within a particular group.
o Example: hematopoietic stem cells: can differentiate into any blood cell type but not neurons, muscle cells, etc.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

Research on embryonic stem cells

A

• Research into ES cells and also using multipotent stem cells, inducing potency via addition of transcription factors, and then putting them back into patients to try and regrow lost tissue.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

The determination and differentiation of a cell depends on the ______ of the cell as well as well as the _______ of the surrounding cells.

A

location

identity

52
Q

inducer

A

cell that sends signal

53
Q

responder

A

cell that receives signal

receiver cells must be Competent: the responder cell must be able to receive the signal.

54
Q

what are the different signals for cell-cell communication

A

autocrine
paracrine
juxtacrine
endocrine

55
Q

autocrine signals

A

act on the same cell that secreted the signal in the first place.

56
Q

paracrine signals

A

act on cells in the local area

57
Q

juxtacrine signals

A

do not usually involve diffusion, but involve a cell directly stimulating receptors on an adjacent cell

58
Q

endocrine signals

A

secreted hormones that travel through the bloodstream to a distant target tissue.

59
Q

growth factors

A

inducers

peptides that promote differentiation and mitosis of certain tissues.

60
Q

reciprocal development

A

something that gets induced then induces something else (the same thing that originally induced it).

61
Q

morphogens

A

use gradients to induce, diffuse throughout the organism.
• Depending on the concentration of the morphogen, it will induce a specific response by the cell. Many different morphogens at once can result in highly specific differentiation (specific signal being received by groups of cells).

62
Q

cell migration

A

 Cells must be able to detach from where they are and migrate to parts of the body to function properly.

63
Q

cell death

A

 Apoptosis: programmed cell death
• Can occur via apoptotic signals or preprogramming
• Ex: our fingers are webbed and then the webbing undergoes apoptosis resulting in separation of the fingers.
• The cell divides into apoptotic blebs, which can then be broken apart into apoptotic bodies and digested by other cells.
o Digested by other cells so harmful chemicals are never released.
 Necrosis: cell death as a result of injury and internal substances are leaked which can cause irritation of nearby tissues.

64
Q

apoptosis

A

programmed cell death
• Can occur via apoptotic signals or preprogramming
• Ex: our fingers are webbed and then the webbing undergoes apoptosis resulting in separation of the fingers.
• The cell divides into apoptotic blebs, which can then be broken apart into apoptotic bodies and digested by other cells.
o Digested by other cells so harmful chemicals are never released.

65
Q

during apoptosis, the cell divides into _______, which can then be broken apart into ________ and digested by other cells.

A

apoptotic blebs

apoptotic bodies

66
Q

necrosis

A

cell death as a result of injury and internal substances are leaked which can cause irritation of nearby tissues.

67
Q

regeneration

A

 Regenerative capacity: the ability of an organism to regrow certain parts of the body, varies from species to species.
 Complete regeneration: the lost or damaged tissues are replaced with identical tissues.
• Stem cells can migrate to and differentiate into the lost tissue
 Incomplete regeneration: the newly formed tissue is not identical in structure or function to the tissue that has been injured or lost.
• Heart has no regenerative capacity while the liver has a lot.

68
Q

regenerative capacity

A

the ability of an organism to regrow certain parts of the body, varies from species to species.

salamanders have a large amount of stem cells so they have a high regenerative capacity.

69
Q

complete regeneration

A

the lost or damaged tissues are replaced with identical tissues.
• Stem cells can migrate to and differentiate into the lost tissue

70
Q

incomplete regeneration

A

the newly formed tissue is not identical in structure or function to the tissue that has been injured or lost.
• Heart has no regenerative capacity while the liver has a lot.

71
Q

senescence

A

biological aging, can occur at the cellular and organismal level as the changes accumulate.

72
Q

cellular level senescence

A

Cells are no longer able to divide properly, possibly due to shortening of telomeres.
• Telomerase prevents this from happening but is only acting in germ cells, fetal cells, and tumor cells.

73
Q

organismal level senescence

A

Changes in the body’s ability to respond to a changing environment.

74
Q

____ in the fetus occurs across the placenta as _____ do not function until birth.

A

Gas exchange

fetal lungs

75
Q

the placenta serves endocrine functions, secreting ______

A

estrogen, progesterone, and human chorionic gonadotropin (hCG)

76
Q

Oxygenation occurs at the placenta, so umbilical arteries carry ______ blood and the umbilical vein carries ______ blood.

A

deoxygenated

oxygenated

77
Q

Maternal and fetal blood cannot mix because ____

A

they may be different blood types

78
Q

fetal hemoglobin (HbF)

A

greater affinity for oxygen than maternal hemoglobin (HbA)

o Helps with transfer and retention of oxygen by HbF

79
Q

umbilical arteries

A

carry blood away from the fetus toward the placenta

deoxygenated

80
Q

umbilical veins

A

carries blood toward the fetus from the placenta.

oxygenated

81
Q

what are the differences between fetal and adult circualtion

A

 Lungs and liver do not function until after birth
 Gas exchange at the placenta (rather than lungs)
 Detoxification and metabolism by mother’s liver
 Nutrients and waste exchange at the placenta

82
Q

what are the names of the 3 shunts of the fetus

A

foramen ovale
ductus arteriosus
ductus venosus

83
Q

what are the shunts used to reroute blood from the lungs

A

foramen ovale

ductus arteriosus

84
Q

what is the shunt to bypass the liver

A

ductus venosus

85
Q

what part of the baby are the shunts used for

A

liver and lungs

86
Q

foramen ovale

A

one-way valve that connects the right atrium to the left atrium.
o Blood entering the right atrium from the inferior vena cava can flow into the left atrium instead of the right ventricle. Pumped through the aorta into systemic circulation directly. Due to pressure gradient where pressure is higher in left side (switched upon birth)

87
Q

ductus arteriosus

A

shunts leftover blood from the pulmonary artery to the aorta. Pressure difference once again pushes blood through this opening and into systemic circulation.

88
Q

ductus venosus

A

shunts the blood returning from the placenta via the umbilical vein directly into the inferior vena cava.

89
Q

ductus venosus

A

shunts the blood returning from the placenta via the umbilical vein directly into the inferior vena cava.

90
Q

placental lungs are filled with ______

A

fluid

91
Q

human gestation lasts _____ weeks

A

40

92
Q

what occurs during the first trimester?

A

organogenesis
o The major organs begin to develop.
o Embryo grows in size.
o Fetus: after 8 weeks, brain is developing, organs have formed, bones harden.

93
Q

what occurs during the second trimester?

A

– movement and face
o Grows, face and fingers take shape
o Begins to move in the amniotic fluid

94
Q

what occurs during the third trimester?

A

antibody transfer
o Rapid growth
o Further brain development
o Antibody transport from mother to fetus increases rate in preparation for outside world.
o At the end, growth slows, and becomes less active because it has less room to move

95
Q

parturition

A

vaginal childbirth
accomplished by rhythmic contractions of uterine smooth muscle, coordinated by prostaglandins and peptide hormone oxytocin.

96
Q

what hormone is responsible for uterine smooth muscle contraction during birth?

A

oxytocin

97
Q

what are the steps of birth?

A

 1. Cervix thins out and amniotic sac ruptures (water breaking)
 2. Strong uterine contractions result in birth
 3. Placenta and umbilical cord are expelled (from mother), known as afterbirth

98
Q

What is the fertilization membrane

A

depolarized and impenetrable membrane that is the result of the cortical reaction (a release of calcium ions into the zygote).

99
Q

cortical granule

A

holds the calcium ions responsible for the cortical reaction upon fertilization.

100
Q

_____ occurs in the fallopian tubes while _______ and _____ occurs in the uterus.

A

fertilization

implantation and growth

101
Q

____ occurs as the zygote moves from the fallopian tubes to the uterus.

A

cleavage

102
Q

what are two things that occur when cleavage occurs

A

increase in the nucleus to cytoplasmic ratio.

increase in the surface area to volume ratio.

103
Q

Blastocyst: the trophoblast gives rise to ____ and the inner cell mass gives rise to _____

A

chorion and placenta

the organism itself

104
Q

draw a blastocyst

A

fluid filled inner cavity surrounded by tropoblast cells with the inner cell mass cells at the top.

105
Q

chorionic villi

A

microscopic finger-like projections that penetrate the endometrium.

106
Q

compare deuterosomes and protostomes

A

Deuterostomes: the blastopore is the anus
Protostomes: the blastopore is the mouth

107
Q

what is selective transcription?

A

only genes needed for a particular cell type are transcribed which allows cells to be different (differentiated)

108
Q

_____ diffuse from organizing cells to the responsive cells

A

inducers

109
Q

the adrenal medulla is derived from the ______ and the adrenal cortex is derived from the _____

A

ectoderm

mesoderm

110
Q

the notocord is a part of the ____ germ layer

A

mesodermal

111
Q

how does induction influence development?

A

Certain cells influence the differentiation of nearby cells. It plays a role in spatial organization and is important for cells that play similar roles or are complementary to each other.

112
Q

when a cell is _____, it is committed to a particular lineage (irreversibly). When the cell ______, it assumes the structure, function, and biochemistry of that cell type.

A

determined

differentiates

113
Q

to create ______, scientists remove the _______ from a _____ created in a laboraotry

A

embryonic stem cell lines, inner cell mass, blastocyst

114
Q

to respond to an inducer signal, a cell must be _____, or able to respond to the inducing signal.

A

competent

115
Q

compare the regenerative capacity of the human heart, kidney, and liver

A

heart has no regenerative capacity
liver has high regenerative capacity
kidneys have moderate regenerative capacity

116
Q

what types of cells express telomerase

A

tumor, germ cells, fetal cells

117
Q

the placenta is where fetal ____, ___, and ____ exchange occurs

A

nutrient, gas, waste

118
Q

fetal and maternal ____ cannot mix because they may be different types

A

blood

119
Q

a _______ is used to move oxygen into the fetal blood stream along with the high affinity of fetal hemoglobin (HbF)

A

concentration gradient

120
Q

fetal lungs do not function until ____

A

birth

121
Q

the crossing of ______ across the placental membrane serves as a protective function

A

antibodies

122
Q

the 3 fetal shunts direct blood away from what fetal organs: ____ and ____

A

liver and lungs

123
Q

what do prostaglandins and oxytocin (peptide hormone) do during birth?

A

coordinate uterine smooth muscle contractions

124
Q

the development stage with the greatest nuclear to cytoplasmic ratio is the _____

A

blastula

125
Q

the neural tube forms from the ____

A

ectoderm

126
Q

the last structure to become fully functional in a developing child during pregnancy is the ____

A

lungs

127
Q

the placenta serves endocrine functions, secreting ______

A

estrogen, progesterone, and human chorionic gonadotropin (hCG)

MCAT Bio (12 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions