Chapter 19 Pt. 1 Flashcards
What are the two ways in which cells divide?
(1) Mitosis
(2) Meiosis
What is a chromosome?
a tightly coiled combination of a DNA molecule and specialized proteins called histones
Chromosomes are a tightly coiled combination of a DNA molecule and specialized proteins called ________
histones
Where are chromosomes found in the cell?
the cell nucleus
_______ combined with the ____ are for support and control of gene activity
histones
DNA
What is a gene?
a specific segment of the DNA that directs the synthesis of a protein, which in turn plays a structural or functional role within the cell
______ are arranged in a fixed sequence
genes
genes determine the expression of a particular ____________ or _____
characteristic
trait
True or False: Genes occur individually
False; genes also occur in pairs
the members of each gene pair are located at the same position on _____________ ____________
homologous chromosomes
What is a somatic cell?
all cells except eggs or sperm have 46 chromosomes
Humans have ___ chromosomes= ___ pairs of chromosomes
46
23
one member of each (of human’s 23) pair comes from the ________ ____ and the _______ ______
mother’s egg
father’s sperm
___________ ____________ _____- a pair being two chromosomes with genes for the same traits
homologous chromosome pairs
homologous chromosome pairs are also known as ___________
homologues
What is a diploid?
any cell with two of each kind of chromosome
What is a sex chromosome?
one of the 23 pairs of chromosomes, that determines whether a person is male or female
What are the two types of sex chromosomes?
X
Y
Someone with two X chromosomes is genetically ________
female
Someone with an XY chromosome is genetically ______
male
What are autosomes?
the other 22 pairs of chromosomes
Autosomes determine the expression of most of a person’s inherited _____________
characteristics
__________ determine the expression of most of a person’s inherited characteristics
Autosomes
