Chapter 3- Meiosis Flashcards

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

Meiosis

A

Cell division in two stages that produces haploid gametes in germline cells
Maintains chromosome number within species

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

Meiosis I

A

Reduction division
Homologous chromosomes separate
Chromosome number reduces from 46 to 23
Crossing over occurs

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

Meiosis II

A

Equational division
Sister chromatids separate
Chromosome number remains constant

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

Mechanisms to Increase Genetic Diversity

A

Crossing Over
Independent Assortment

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

Alpha Thalassemia

A

Misalignment of alpha globin genes can lead to duplication-deletion events
Missing 1+ copies of alpha globin gene leads to globin imbalance and buildup of beta chains

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

Spermatogenesis

A

Spermatogonium- Primary Spermatocyte- Secondary Spermatocyte- Sptermatid- Spermatozoa
Continuous division and maturation after puberty
I spermatogonium produces 4 sperm

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

Oogenesis

A

Oogonium- Primary oocyte- Secondary oocyte- Ovum
Produce polar bodies during each meiotic division
Begins during utero, Meiosis I finishes during ovulation, Meiosis II completed during fertilization

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

Stages of Embryonic Development

A

Fertilization
Cleavage
Gastrulation
Neurulation
Neural Crest Development
Organogenesis

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

Fertilization

A

Matured sperm meets oocyte in fallopian tube
Sperm DNA enters oocyte
Meiosis II finishes and induces polarity relative to entry site

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

Cleavage

A

Frequent Mitotic divisions to increase cell number
~4 days- 16 cells, morula
Blastocyst- Hollow mass of 100 cells
Trophoblast- Outer layer, becomes chorion and amnio
Inner cell mass becomes embryo
Implantation occurs around day 7

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

Gastrulation

A

Invagination and migration to form 3 primary germ layers
Ectoderm- Skin and nervous system
Mesoderm- Muscle
Endoderm- Tracts
Days 14-28

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

Neurulation

A

Initiation of organogeneis at weeks 3-4
Ectoderm divides into neural tube and crest
Neural tube folds and pinches off to become CNS
Adjacent neural crest migrate to become pigment and distal neurons and smooth muscle

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

Organogenesis

A

Transformation of germ layers into distinct organs
All organs present by week 8- Fetus

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

Morphogenesis

A

Process by which order is created in an organism
Mediated by cell growth, migration, interaction and death
Mediated by growth factors and hormones

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

Processes of morphogenesis

A

Axis specification, pattern formation, an dorganogenesis

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

Paracrine Developmental Mediators

A

Extracellular Growth Factors
Fibroblast growth factor (FGF) Family
Hedgehog Family

17
Q

Transcription Factors mediating development

A

Regulate gene expression and differentiation
HOX, PAX, and T-BOX Families

18
Q

Sonic Hedgehog (Shh)

A

Transcription regulating protein with axis specification
Shh binds to patched, removes smothened inhibition
Activates GLI Transcription factors

19
Q

Homeobox (HOX) Genes

A

Conserved transcription factors that regulate body segmentation
Differential combinations create segments

20
Q

Pattern formationi

A

Axis specification-
Dorsal/ventral
Anterior/posterior
Right/left

21
Q

Limb formation

A

Mesoderm cells divide and protrude forming limb bud
Apical Ectodermal Ridge (AER) cells on end regulate proximal/distal growth
Zone of Polarizing Activity (ZPA) found under AER releases Shh to regulate anterior-posterior development

22
Q

Congenital Abnormalities

A

Birth defects in structure or function from intrauterine life

23
Q

Dysmorphology

A

Study of congenital birth defects that alter form of newborn
Determine maternal health, environmental, and genetic contributions

24
Q

Syndromic Abnormality Pattern

A

Causative agent causes defects in parallel

25
Q

Brachio-oto-renal dysplasia

A

Error in conserved ear and kidney genes causes ear, neck, and kidney abnormalities

26
Q

Sequential Abnormality Pattern

A

Defects in single organ cause further symptoms

27
Q

Robin Sequence

A

U-shaped cleft palate and small mandible
Mandibular restriction cause posterior tongue alignment, disrupts palate shelves, creates cleft palate

28
Q

Malformations

A

Intrinsic error in embryonic tissue formation
Genetic, maternal diabetes or medication, or infection as potential causes

29
Q

Deformation

A

Abnormal form or position of body region
Caused by extrinsic factors impinging on fetal development thru 35-38 weeks
Malformed uterus, crowding, or decreases in amniotic fluid

30
Q

Disruptions

A

Extrinsic factors destroy fetal tissue
Vascular insufficiency, trauma, or teratogens

31
Q

Teratogens

A

Chemical or other agents that cause birth defects
Thalidomide, cocaine, cigarettes, alcohol, viruses, nutrient excess

32
Q

Factors influencing teratogenicity

A

Timing, dosage, and duration
Ability to cross placenta
Maternal and fetal genetic susceptibility
Mechanism of action

33
Q

Hirschsprung Disease (HSCR)

A

Congenital megacolon caused by neural crest failure to innervate internal anal sphincter
Bowel becomes dilated via obstruction
Mortality due to ruptured colon

34
Q

Gorlin Syndrome

A

Mutation in patch 1 in Shh pathway
Patch 1 acts as tumor suppressant
Increased risk of cancer and de novo mutations

35
Q

Hutchinson-Fuilford Progeria Syndrome (Progeria)

A

Disorder of accelerated aging
Mutations in LMNA Gene- Encodes lamin A
Abnormal Lamin A- Progerin- Unstable nuclear envelope
Increased DNA damage- Growth failure
Baldness, cranial defects
Loss of body fat, dry scaly skin, stiff joints
Cardiovascular issues and insulin resistance

36
Q

Traits associated with longevity

A

Insulin resistance
Control of cell cycle
Lipid metabolism
Immune and stress responses
Antioxidant enzyme expression
Nutrient metabolism