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Outline Notes Chapter 6 – Chromosomes and Cell Reproduction
6.1 – Chromosomes
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V.
New Cells are formed by Cell Division
a. _______________cells are produced by our bodies every day
b. Cell division is also called cell ________________
c. cell division differs depending on the organism and why the cell is dividing
d. ______________are an organisms reproductive cells (sperm and eggs)
e. ______________must be present in all new cells
i. When a cell divides, the DNA is first __________and then distributed so each cell ends up with a
complete copy of the DNA
Bacterial cells divide to _____________
a. Bacteria reproduce by a process called ________________ ________________
i. Binary fission is a form of __________reproduction that produces ____________offspring
1. A single parent passes __________copies of all of its DNA to its offspring
2. Binary fission occurs in _____ stages
a. First, DNA is _________
b. Second, the cell __________
Eukaryotic Cells form Chromosomes before cell division ***draw a picture to the right!!!
a. __________– a segment of DNA that codes for a protein or RNA molecule
i. a single strand of DNA has thousands of genes
b. ____________– coiled DNA structure
c. _____________– 2 exact copies of DNA that make up each chromosome
d. _____________– The point at which the 2 chromatids of a chromosome are attached
Chromosome number and structure affect Development
a. Each human __________cell (body cell – any other cell than the sperm and egg) normally has two copies
of ___ different chromosomes, for a total of _____.
b. Possession of all chromosomes is essential for _______________
c. Sets of Chromosomes
i. ______________Chromosomes – chromosomes that are similar in size, shape, and genetic
content
1. AKA – Homologues – each homologue comes from one of the two parents
2. ________– when a cell contains 2 sets of chromosomes
a. Diploid number – 2n = ____
3. ________– when a cell contains 1 set of chromosomes
a. Example – ___________– sex cells
b. Haploid number – n = ______
ii. _______________– fusion of 2 haploid gametes which forms a diploid zygote
1. _______– is a fertilized egg cell
iii. Each organism has a characteristic number of chromosomes – but it is constant within a species.
1. ** Which organisms have more chromosomes than humans? Less??
Chromosomes determine your sex
a. ________________– chromosomes that are not involved in determining sex (gender)
i. IN humans there are _________ pairs of autosomes
b. _____________________– contain genes that will determine the sex of the individual
i. In humans there are ____ pair of sex chromosomes
ii. The 2 sex chromosomes in humans are ___ and ____
1. Any individual with a ____ chromosome is a boy (male) – X__
2. Any individual without a Y is a female – X__
VI.
VII.
Change in Chromosome number
a. Humans who are missing even one of the 46 chromosomes do not __________
b. Humans with more than 2 copies of a chromosome called___________, will not develop properly
i. __________Syndrome – Trisomy 21 – is an extra copy of Chromosome #21
c. __________- a photo of chromosomes arranged by size
d. _____________-- each chromosome and its homologue separates
e. ______________– when one or more chromosomes fail to separate properly
Change in Chromosome structure
a. ________________– change in chromosome structure
i. _____________ – piece of chromosome breaks off
1. Usually fatal to the zygote (fertilized egg)
ii. ____________ -- a chromosome fragment attaches to a homologous chromosome
iii. ____________ -- piece reattaches to original chromosome but in reverse orientation
iv. ____________ – piece reattaches to a non-homologous chromosome