CHAPTER 6 CELL REPRODUCTION
_______________________ - 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.
______________________ - A set of chromosomes present in a somatic cell (body cell). Ex: 46, XX = normal female; 46, XY = normal male
Somatic Cell (Body Cell)
Gamete (Sex Cell: sperm/ ovum)
Do not occur in pairs
Exist throughout the body
2 homologues of each chromosome
Only ONE of each chromosome
__________________ 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 23rd 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, ______ & ______.
Genetic Diseases that Occur with an Abnormal Number of Chromosomes
Also referred to as "____________________________" Karyotype - ____________ Phenotype (Physical characteristics caused by an abnormal genotype, or
genetic make-up) 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) Karyotype - __________ Phenotype Occurs in 1/ 5,000 live births (PICTURE) Karyotype - ____________ Phenotype (PICTURE)
Also referred to as "____________________________"
Karyotype - ____________
Phenotype (Physical characteristics caused by an abnormal genotype, or genetic make-up)
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
Karyotype - __________
Occurs in 1/ 5,000 live births
Karyotype - ____________
Mitosis and Cell Division
Prokaryotic Cell Division (How BACTERIA reproduce)
_____________________________ - Process by which bacteria reproduce
Eukaryotic Cell Division
_____________________________ - Process by which a eukaryotic cell nucleus divides to form 2 nuclei, each containing a complete set of the cells 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.
(CELL CYCLE DIAGRAM)
Phases of Mitosis
Controlling the Cell Cycle
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 cells progress through the phases of the cell cycle.
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:
________________________ - 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 1st 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:
This acts as a ________________________________________________________________, which allows ___________________ ____________________ to occur.
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