_______________________ - A "library" of genetic information. Consists of one long strand of __________ (_______%) wrapped around chunks of associated _________________ (________%). This occurs because all of the __________ needed in a cell cannot fit. Each chromosome contains thousands of _____________.

_______________________ - Joined strands off duplicated genetic material.

_______________________ - A protein disk that attaches chromatids to each other in a chromosome.

Chromosome Diagram

__________________ cells have _______ chromosomes, or ________ PAIRS of chromosomes Each pair of chromosomes #1 -> 23 in the cell is identical to one another, and contains the same _____________ in the same order.

___________________________ - Chromosomes # 1 -> 22 in the body. These are referred to as somatic cells, and they may be found ___________________________________________.

___________________________ - The 23^rd set of chromosomes. These chromosomes determine the sex of an individual, male or female. They are designated as "_____" & "_____"

EXAMPLE: Female Karyotype = _________

Male Karyotype = _________

The sex of a child is determined by the ___________________ of that child. This is because females only have only type of sex chromosome to contribute to the child, _____ . Males, on the other hand, have both types of sex chromosomes to contribute, ______ & ______.

Also referred to as "____________________________"

Karyotype - ____________

Phenotype (Physical characteristics caused by an abnormal genotype, or genetic make-up)

• Mental retardation
• Cardiac anomalies
• Mongolian slant to the eyes
• Simean crease in hand

This is the most common genetic cause of mental retardation

Occurs in 1/800 live births

Higher incidence among mother over 35 years of age

(PICTURE)

 

 

 

 

• ___________________________ - ___________________ one sex chromosome, _____

Karyotype - __________

Phenotype

• Short stature
• Gonadal dysgenesis
• Webbed neck
• Widely spaced nipples, broad chest
• Kidney & heart abnormalities

Occurs in 1/ 5,000 live births

(PICTURE)

 

 

 

• ___________________________ - One _____________ sex chromosome, _____

Karyotype - ____________

Phenotype

• Tall, thin individuals with long limbs
• May display both female and female secondary sex characteristics
• 1/ 1,000 live male births
• infertile
• 2/3 suffer from educational problems (dyslexia)
• poor psychosocial adjustment

 (PICTURE)

Prokaryotic Cell Division (How BACTERIA reproduce)

_____________________________ - Process by which bacteria reproduce

• Bacterium becomes _____________
• _________ is copied
• Copy of chromosome attaches to a part of the inner __________________
• New membrane & wall materials begin to form between the two ___________________ near the middle of the cell
• Cell _________________ inward, and splits into ___________________________________

Eukaryotic Cell Division

_____________________________ - Process by which a eukaryotic cell nucleus divides to form 2 nuclei, each containing a complete set of the cell’s chromosomes. In most cells, mitosis is followed by….

_____________________________ - Division of the original cell into 2 separate cells, each with its own nucleus.

________________ cells have cell walls that resist being ________________ _____________ like __________________ cell membranes. So they __________________________________ in the center of the cell. The new cell wall divides in half, resulting in _____________________.

After _____________________ & _________________________, each of the 2 new cells formed from the parent cell contains ______________ ________________ of all the ______________________ present in the ________________ cell.

The Cell Cycle

_____________________________ - Cycle of growth & division of a cell.

5 Phases of the Cell Cycle

_____________________________ - Most active phase of the cell cycle. Food is taken in, wastes eliminated, energy is converted, growth & differentiation occur. Cell makes copies of genetic material and duplicates organelles.

1. __________________________ - "First gap" Intense growth occurs. This phase occupies most of the cell’s life.
2. __________________________ - "Synthesis" The cell copies molecules of DNA in each of its chromosomes. These two molecules remain together, joined at the centromere
3. __________________________ - "Second Gap" Cell continues to grow & prepares for cell division. Cell duplicates organelles.
4. __________________________ - "Mitosis" Chromosomes arrange themselves along the "equator," or middle of the cell, and separate.
5. __________________________ - "Cytokinesis" Cell divides in half and becomes two new, identical cells.

 (CELL CYCLE DIAGRAM) 

Phases of Mitosis 

 (MITOSIS DIAGRAM)

• ___________________________ - Mitosis begins. Chromosomes coil into short, fat rods. Nuclear envelope breaks up, and a network of protein cables called _______________ _________________ assembles across the cell.

• ___________________________ - Chromosomes attach to _________________________ and ____________________ along the _________________ of the cell

• ___________________________ - Each chromosome separates from its identical copy. Centromeres ________________. Chromosomes are _________________ to __________________________________ of the cell. Spindle fibers break down.

• ___________________________ - Each side of the cell now has a complete set of _____________________. __________________ ___________________ forms around each new set of chromosomes. Chromosomes _________________ so that proteins can be built, and spindle fibers disappear.

Researchers have discovered that animal cells use a class of proteins called _______________ to help control different phases of the ________________ _________________.

________________________ - Stimulates DNA replication in S phase

________________________ - Stimulates Mitosis

Cyclins are influenced by another class of proteins, called _____________________________. These proteins supervise & monitor a cell’s progress through the phases of the cell cycle.

They can:

• ____________________________ that make specific cyclins
• ____________________________ of cyclins

This keeps the cell cycle in check, and prevents unnecessary __________________________.

Cancer Arises from a Faulty Cell Cycle

If the _______________________ _________________________ fails, cells can grow & divide without restraint. This result is a clump of cells called a ___________________.

Tumors may be:

• ______________________ - Stay in the region it originally formed.

• ______________________ - Continue to grow & invade other tissues.

________________________ - A disease characterized by uncontrolled cell division & growth

________________________ - A change in an amino acid sequence of a gene. It may be a random, spontaneous mistake or caused by exposure to environmental mutagens.

________________________ - A piece of a chromosome breaks off & reattaches itself to a non-homologous chromosome. Many cancers result in this, but this may also be random, resulting in Down Syndrome, or other forms of chromosomal abnormalities in individuals.

________________________ - A two-stage form of nuclear division in which the chromosome number is __________________. This is the manner in which ______________ are formed. Meiosis is often called ___________________ ____________________, because ______________ cells divide to become ________________ cells.

________________________ - A reproductive cell (egg or sperm). They are "_____________" ie, they contain _________ chromosomes in humans ("______").

Why do sperm & egg cells need to be haploid?

In sexual reproduction, _____ gametes fuse to form the 1^st cell of a new individual.

In __________________________, or the _________________________________________, the number of chromosomes is cut in __________ by the separation of ____________________ ______________________.

In __________________________, or the _________________________________________, identical copies of chromosomes are separated into ___________________. ______________ _____________________ occurs, producing _____________ __________________ cells.

 Importance of Crossing Over

_____________________________ - Exchange of corresponding segments of DNA during meiosis, when pairs of homologous chromosomes are held tightly together.

Crossing over results in: