Biology II

Cell cycle

Series of events that cells go through as they grow and divide

Diploid cells

Somatic and stem cells 23 pairs

Haploid

Gametes 23 chromosomes

Cell cycle

G1, S, G2, M

Cell cycle somatic and gametes

Somatic goes through mitosis and gametes meiosis

Necrosis

Cell death affected by external sources

Apoptosis

Cell auto-destruction

Interphase

G1, S, G2

G1

Cell increases in size

Synthesis

Chromosomes are duplicated and the synthesis of DNA molecules takes place

G2 phase

many of the organelles and molecules required for cell division are produced

M phase

prophase, metaphase, anaphase, telophase

Prophase

Nuclear envelope disappears
DNA is condensed into chromosomes
Centrioles move to the opposite hemispheres
Mitotic spindle is produced from the centrioles

Metaphase

The cell elongates
The chromosomes line up in the center
The spindle hold the chromosomes by their centromeres

Anaphase

Chromosomes split, half goes to one side (spindle pulls) and the other to the opposite

Telophase

DNA uncondensed
Nuclear envelope reappears
Spindle disappears
Formation of cleavage

Cytokinesis

The cell fully divides into cell daughters

Mitosis

(Stem and Somatic) (1 division) Divides into 2 new daughters with exactly the same information and same set

Meiosis

2 cell divisions
The first one is diploid and the 2 has a different sortment of the genetic material

Karyotype

A display of the chromosome that we have in a cell

Autosomes

Any chromosome that is not a sex chromosome (1-22)

Production of gametes (men)

Sperms - Spermatenogenesis - Meiosis

Production of gametes (women)

Eggs - Oogenesis - Happens on ovaries (4 cells, the one that is mature goes)

Fertilization

Sperm-egg fusion

after fertilization

The Zygote is created (1 new cell, diplod)

Moral

Cluster of cells (not an embrion) - Differenciation

Asexual reproduction

Vegetative propagation, budding, fragmentation, binnary fussion, sporelation, parthenogenesis

Vegetative propagation

Part of a plant is separated from the parent and grows into a new identical part, plant produces different structures.

Vegetative propagation examples

Tulips, onions, risoms, ginger

Budding

Organism splits off a small part of themselves to grow into a new organism (small budd)

Budding examples

Amoeba, Coral, Cacti, Hydra, Jellyfish

Fragmentation

A piece break off and grow into new individuals (genetically identical)

Fragmentation examples

Starfish, Worms, Sponges

Binnary fission

Single parent cell doubles its DNA, then divides into 2 cells

Sporelation

Every single spore can develop into a new individual

Sporelation examples

Fungi, liveworms, moses, ferms

Parthenogenesis

Egg develops without being fertilized, only females

Parthenogenesis examples

Ants, bees, salamanders

Sexual reproduction

Internal fecundation, external fecundation and hermaphroditism

Internal fecundation

Inside the female, advantage of protecting the egg

Internal fecundation examples

Humans, dogs, cats

External fecundation

Aquatic, humid environments

External fecundation examples

Fish, frogs, crustacea, corals

Hermaphroditism

individual may have both male and female reproductive systems, they can self-fertilize and change

Hermaphroditism examples

Snales, slugs, linchs, clownfish

Mendel's Principles

Principle of dominance, principle of segregation, and principle of independent assortment

Principle of dominance

Some alleles are dominant, and others are recessive

Principle of segregation

When any individual produces gametes, the copies of a gene separate so that each gamete receive only one copy (allele).

Principle of independent assortment

Genes from different traits can segregate independently during the formation of gametes

Types of genetic disorders

Monogenic, Multifactorial, Chromosomal

Monogenic

caused by a mutation in one gene

Multifactorial

mutation in multiple genes by a combination of gene mutations and environmental factors

Chromosomal

Changes in the number or structure of entire chromosome

Chromosomal genetic disorder classification

Sex linked, Autosomal, Aneuploidy

Sex linked

Mutation in only sex chromosomes, there is y - linked (only men affected) and x - linked

Autosomal

Mutation between 1st to 22nd pair of chromosomes

Aneuploidy

Missing or extra chromosomes, it's a mutation due to external factors (radiation, drugs, alcohol, tobacco), hence it's not inherited.

Sex-linked inheritance

Hemophilia, Color blindness, Duchenne muscular dystrophy (DMD), Azoospermia, Abnormal testicular development, Retinitis pigmentosa.

Hemophilia

Blood clotting gene is carried on the X chromosome
The royal disease
Disorder characterized by the inability to properly form blood clots
This results in abnormally heavy bleeding that will not stop, even from a small cut

Factors for Hemophilia (x-linked)

Factor VIII - A
Factor IX - B (christmas disease)

Color blindness (x-linked)

Group of conditions that affect the perception of color
Red-green color vision defects are the most common form of color vision deficiency
\____________ will be expressed in males with a higher probability than in females

Types of Color blindness

Deuteranopia: M - cones affected (green)
Protanopia: S - cones affected (red)
Tritanopia: L - cones affected (blue)
Monochromacy: the 3 cones are affected alongside the rods.

Duchenne muscular dystrophy (DMD) (x-linked)

Genetic disorder characterized by progressive muscle degeneration and weakness.
The disease primarily affects boys, but in rare cases it can affect girls.
The affected child might have difficulty jumping, running, and walking, enlargement of the calves, waddling gait, scoliosis, respiratory failure.

Azoospermia (y-linked)

\____________ means there's no sperm in a man's ejaculate. \___________ leads to male infertility.
Infertility, low sex drive, erectile dysfunction, lump, swelling, or discomfort around the testicles, decreased hair on the face or body.

Abnormal testicular development (y-linked)

Several abnormalities in males caused by Y chromosome mutations, may be caused due to harmful environmental factors that disrupt embryonal programming and genetic factors
Poor semen quality, testicular cancer, undescended testes, hypospadias, low birth weight

Retinitis pigmentosa (y-linked)

Eye diseases that affect the retina. \___________ makes cells in the retina break down slowly over time, causing vision loss.
Hard time seeing in poor lighting or in the dark, a reduced ability to see either central vision or side or peripheral vision, hard time reading print., hard time figuring out detailed images, hard time with stumbling or tripping over objects not seen.

Autosomal

Albinism, Sickle cell anemia, Polydactyly, Hutchinson Gilford (progeria), Tay-Sachs disease

Albinism (recessive)

Group of inherited disorders where there is little or no production of the piment melanin

Sickle cell anemia (recessive)

Affects hemoglobin and structure of red blood cells, which are crescent, or "sickle" shaped

Polydactyly (dominant)

Abnormality characterized by extra fingers or toes. The condition may be present as part of a collection of abnormalities, or may exist by itself.

Hutchinson Gilford (progeria) (dominant)

Genetic condition characterized by the dramatic, rapid appearance of aging beginning in childhood.
Slowed growth, with below-average height and weight, narrowed face, small lower jaw, thin lips and beaked nose, prominent eyes and incomplete closure of the eyelids, hair loss, including eyelashes and eyebrows, thinning, spotty, wrinkled skin, visible veins.

Tay-Sachs disease (recessive)

\____________ is caused by a baby receiving two defective HEXA genes, one from each parent. Babies born with \___________ often die at a young age.
"Cherry-red" spots in the eyes, loss of motor skills, muscle weakness, progressing to paralysis, vision loss and blindness, hearing loss and deafness, problems swallowing, loss of mental functions

Aneuploidies (not inherited)

Turner syndrome, Klinefelter syndrome, Edward's syndrome (Trisomy 18), Patau syndrome (Trisomy 13), Triple X syndrome (XXX), Jacob's syndrome (XYY), Down syndrome.

Turner syndrome

Caused by a missing or incomplete x chromosome
Some of the genes on the X chromosome are involved in growth and sexual development, which is why girls with the disorder are shorter than normal and have incompletely developed sexual characteristics

Klinefelter syndrome (XXY)

Affected individuals typically have small testes that don't produce as much testosterone as usual.
poor beard growing, narrow shoulders, breast development, female type pubic hair, small testicular size, fewer chest hair, long arms and legs, frontal baldness absent

Edward's syndrome (trisomy 18)

small, abnormally shaped head; a small jaw and moth; and clenched fists with overlapping fingers
Many individuals with \__________ die before birth or within their first month.

Patau syndrome (trisomy 13)

Heart defects, brain, spinal cord abnormalities, very small or poorly developed eyes (microphthalmia), extra fingers or toes, an opening in the lip (a cleft lip)
De to presence of several life-threatening medical problems, many infants with \__________ die within their first days or weeks of life

Triple X syndrome (XXX)

Females with this condition may be taller than average
Associated with an increased risk of learning disabilities and delayed development of speech and language skills.

Jacob's syndrome (XYY)

Affected children can have delayed development of motor skills or weak muscle tone
Individuals with this syndrome have an increased risk of behavioral, social and emotional difficulties

Down syndrome (trisomy 21)

\____________ is a condition in which a person has an extra chromosome
A flattened face, especially the bridge of the nose, a short neck, a tongue that tends to stick out of the mouth, tiny white spots on the iris (colored part) of the eye, a single line across the palm of the hand (palmar crease), small pinky fingers that sometimes curve toward the thumb, poor muscle tone or loose joints