GENBIO Q2

Chromosome

coiled DNA

Chromatid

single strand of a duplicated chromosome

held together by a centromere

Fertilization

union of sperm and egg cell

sexual reproduction

produces zygote

Germ Cells

produced in sex organs

way in which traits can be passed down

develop into sex cells upon maturity or puberty

Spermatogenesis

making sperm

Oogenesis

making egg cell

Meiosis

production of sex cells with haploid chromosomes

undergoes two rounds of cytokinesis

also called reduction division

reduces chromosome number into half

restoration of original chromosome number occurs during fertilization

ultimately produces four daughter cells with a reduced chromosome number

Meiosis I

division of homologous chromosome

produces two haploid cells with duplicated chromosome

begins after G2

chromosomes are in sister chromatid conformation

starts with duplicated chromosomes

Homologous Chromosomes

set of chromosomes with the same length and appearance

contain same gene coding of a trait but not entirely indentical

Karyotyping

used to view arranged chromosomes

using karyogram

Prophase I

- chromosome condensation

- synapsis between homologous pairs

- crossing over between homologous pairs

- pairing of homologous chromosome

Metaphase I

- alignment of homologous chromosomes the center

- maternal and paternal chromosomes are randomly arranged

- facilates reduction in chromosome number

Anaphase I

separation of homologous pairs

maternal and paternal members move to either pole

Telophase I and Cytokinesis

chromosomes reach opposite poles

chromosomes reach opposite poles

cytoplasm divides

Meiosis II

divides sister chromatids

results in sex cells with only half the chromosome number

Autosome

chromosome pair 1 to 22

Sex chromosome

23rd chromosome pair

x and y chromosome

1)Reduction of genetic material and sexual reproduction
2)Inheritance
3)Genetic diversity
4)Survival

Significance of Meiosis:

stem cell technology

genetic engineering

application of meiosis and mitosis

Stem Cell Technology

applications of stem cell therapy range from genetic disorders to injuries

Genetic engineering

meiosis produces new cell variants

 mitosis proliferates genetically modified cells

Corn Plants

genetically manipulated to impart desirable traits such as resistance to pests and drought conditions

Cancer

disorder that result from the malfunction of the cell during the cell cycle

uncontrolled cell division

 

brain

respiratory

lymph nodes

liver

skeletal

Common sites of cancer metastasis:

brain

- headaches

- seizures

- vertigo

Respiratory

cough

hemoptysis

dyspnea

lymph nodes

lymphadenopathy

Liver

hepatomegaly

jaundice

Skeletal

pain

fractures

spinal cord compression

1)Heredity
2)Cigarettes and alcohol
3)Obesity
4)Exposure to radiation
5)Exposure to carcinogens
6)Exposure to pollution

Factors that cause cancer:

independent assortment

crossing-over

random fertilization

mechanisms that contribute to genetic variation

Independent Assortment

random distribution of homologous chromosomes

Crossing-Over

- homologous chromosomes transfer or exchange genetic information

- during Prophase I

- contributes to recombinant chromosomes that result in genetic variation

Random Fertilization

random fusion of two gametes in fertilization

Nondisjunction

when chromosomes don’t separate correctly

cell can receive two many or too few

turner syndrome

down syndrome

trisomy x

klinefelter syndrome

genetic disorders associated with meisosis

Turner Syndrome (45, XO)

-chromosomal disorder in females

-missing or partially missing X chromosome

-short stature, webbed neck, low hairline

Down Syndrome (Trisomy 21)

-presence of all or part of a third copy of chromosome 21

-slanting eyes, short neck, flat nose and face

Klinefelter Syndrome (47, XXY)

-genetic disorder in males

- presence of an extra X chromosome

- reduced body muscle mass, body hair, gynecomnastia

trisomy X (47,XXX)

chromosomal disorder in females

involves an extra X chromosomes

taller than average, learning disabilities, ADHD

Cell Membrane

-primary barrier of the cell
 - receives information

  - allows cell to move and grow

  - selective barrier or a semipermeable barrier

  - made up of a bilary layer

  - aqueous nature of intracellular and extracellular environments help form the bilary layer

  - described as a fluid mosaic: important molecules are embedded into its structure

 

1)Phospholipids
2)Proteins
3)Cholesterol
4)Carbohydrates

Cell Membrane Molecules or Structure:

Cholesterol

prevents membrane to become too fluid at high temperature

prevents membrane to become too solid at low temperature

maintains fluidity

Fluidity

imparts flexibility

important for moving cells

allows synthesized membrane proteins or phospholipids to be easily incorporated into the membrane

Double bonds in fatty acids

helps maintain fluidity

saturated and unsaturated

types of fatty acid

saturated fatty acid

- straight tail or viscous

- push against each other at low temperature

- makes the membrane more rigid

unsaturated fatty acid

- kinky tail

- push adjacent phospholipids

- maintain fluidity at low temperatures

 - helps cell move

transport

adhesion

receptor

recognition

types of membrane proteins

> Channel protein
> Carrier protein

types of transport protei

Adhesion protein

protein that fasten adjacent cells

Recognition protein

protein that recognize pathogens

Receptor

protein that allow specific molecules to bind

Carbohydrate Chains

occur on the outside of the lipid bilayer or on the peripheral proteins

defines the cell’s unique characteristics and identify chemical signals

for cell communication

phospholipid

layer consisting of hydrophilic heads and hydrophobic tails

Polar molecule and large molecules

cannot enter cell membrane

requires energy to enter cell membrane

Lipids, alcohol, small molecules

free to move across the cell membrane
Ex. Nitrogen, oxygen, carbon dioxide, water

1)Passive Transport Mechanism
2)Active Transport Mechanism
3)Vesicular or Bulk Transport Mechanism

Substance transport across the cell membrane:

Passive Transport Mechanism

from greater concentration to lower concentration

simple diffusion

osmosis

facilitated diffusion

types of passive transport mechanism

Simple Diffusion

-molecules spread in air from a greater concentration to a point of lesser concentration

 -to attain equilibrium

- no energy required

temperature

pressure

concentration gradient

solvent density

solute solubility

- diffusion of a solute within a solvent is affected by:

Osmosis

diffusion of water molecules across cell membrane

from high water concentration to low water concentration

Tonicity

ability of a solution to cause cell to gain or lose water

depends on the solute concentration

 relative concentration of solutes in fluids

isotonic

hypotonic

hypertonic

types of tonicity

Isotonic

water and solute concentration is equal

water molecules move at same rate in both directions

hypotonic

less solute outside, more inside cell

more water outside, less inside

water moves towards the cell

Cytolysis

cell swells from too much water

caused by hypotonic

hypertonic

more solute outside, less inside cell

less water outside, more water inside cell

water moves outwards

Plasmolysis

cell shrinks or shrivel from lack of water

Lysis

breaking of cell

water potential

 - movement of water molecules as they undergo osmosis

osmotic pressure

- difference in the level of two solutions after osmosis

crenation

- when blood cells wilt

  - from latin crenatus meaning wrinkled

facilitated Diffusion

-movement down a gradient with the aid of transport protein

- molecules such as ions,amino acids, and sugar are transported across the cell membrane, facilitated by channel proteins

Aquaporin

channel where water passes through

Active Transport Mechanism

-from lower concentration to higher concentration

- occurs with energy expenditure

  - have large number of mitochondria

  - important in muscle and nerve cell

  - goes against concentration gradient

Sodium-Potassium Pump

- sodium-potassium protein has an initial shape that binds it to 3 sodium ions

   - phosphate from an ATP molecule is added to carrier protein, carrying the sodium ions across the membrane. It makes a new shape

   - the new shape picks up two potassium ions

   - the phosphate that was added previously was released

   - two potassium ions are released

Vesicles

structures within or outside of cell with a cytoplasm enclosed by a lipid bilayer

formed during secretion, uptake and transport of molecule

produced by golgi body

Bulk or Vesicular Transport Mechanism

transport for large molecules in and out of cells

through vesicles

large molecules

 - proteins, lipids, nucleic acid, carbohydrates and other polysaccharide

exocytosis

endocytosis

types of vesicular transport mechanism

Exocytosis

-molecules from cell fuses with plasma membrane to go outside

- golgi bodies are involved

- uses intracellular vesicles

- for hormones, neurotransmitters, digestive enzymes

constitutive

regulated

types of exocytosis

Constitutive

transports molecules through vesicles

Regulated

transports molecules because of a triggered signal

Endocytosis

vesicles bud inward from cell membrane

 later invaginates to envelope substances

vesicles delivers its content

molecules from the cell being transported into the cell

phagocytosis

pinocytosis

receptor-mediated endocytosis

types of endocytosis

phagocytosis

- cell eating

   - cells take in large particles or solid through infolding of the cell membrane to form endocytic vesicles

   - exhibited by white blood cell

   - engulfing and packing through vacuole

   - vacuole fuses with the lysosome and molecule will be digested

   - for defense and repair for human body

pinocytosis

- cell drinking

   - any solute or small particles in the fluid will be moved into the cell

   - vesicles form around liquid or around very small particles

   - for ingestion

Receptor-mediated endocytosis

- uses receptor protein to recognize compatible molecules

   - for the regulation of molecules into the cell

   - involved in the uptake, transfer, and exchange of substances between cells