Biology Chapter 12
A(n) ______ is a portion of DNA that encodes a protein.
gene
A cell with one set of chromosomes is a(n) ______ cell.
haploid
A ______ organism produces mixed offspring: some that are identical to the parent plant and some that are different.
hybrid
Cell division that results in the production of gametes is called
meiosis
What type of trait in Mendel's studies could vanish in one generation and reappear in the next generation?
recessive
In the human genome, the X and Y chromosomes are called the
sex chromosomes.
A ______ organism always produces offspring that are identical to the parent when self-fertilized.
true-breeding
Alternative forms of a gene are called
Blank 1: alleles, Alelles, allele, or alelle
In the nucleus of eukaryotic cells, all of the DNA is divided into multiple ____________ , which are continuous, long strands of DNA wrapped around proteins.
Blank 1: chromosomes, linear chromosomes, or chromosome
A(n) _________ allele always exerts its effects when present.
Blank 1: dominant
In humans, sex is determined by the sex chromosomes X and Y. If a human contains two X chromosomes, then its biological sex is typically ___________ ; but if a human contains an X chromosome and a Y chromosome, then its biological sex is typically __________
Blank 1: female, girl, or woman Blank 2: male, boy, or man
The union of gametes to form a zygote occurs during a process called
Blank 1: fertilization or sexual reproduction
Gametes, or sex cells, are _______, meaning they contain only one set of chromosomes.
Blank 1: haploid, haploid cells, or haploid cell
Gametes, or sex cells, are __________, meaning they contain only one set of chromosomes.
Blank 1: haploid, haploid cells, or haploid cell
A cell division process called _________ shuffles the genetic information contained in chromosomes and produces cells called gametes. Gametes are _____________ reproductive , Incorrect Unavailable cells because they only have one copy of each chromosome. _________________ unites sperm and egg to form a zygote, which has two copies of each chromosome and is therefore a(n) _____________ cell.
Blank 1: meiosis Blank 2: haploid or sex Blank 3: Fertilization or fertilization Blank 4: diploid
What is a sequence of DNA nucleotides that holds the instructions to make a protein?
Gene
Who discovered the basic principles of inheritance using traits of pea plants?
Gregor Mendel
______ is the cell division process that occurs in diploid germ cells and gives rise to haploid cells.
Meiosis
______ formulated key principles of genetics before DNA, genes, and chromosomes were discovered.
Mendel
Rank the hereditary components from smallest at the top to largest at the bottom.
Nucleotide Gene Chromosome Gamete
Different varieties of the same gene, called ______, may arise from mutations.
alleles
In the human genome, 22 of the 23 pairs of chromosomes are called
autosomes
Of the 23 pairs of human chromosomes, the 22 pairs of chromosomes that are the same in both sexes and are not sex chromosomes are called the
autosomes
Long strands of DNA and their associated proteins are called
chromosomes
A cell with two complete sets of chromosomes is a
diploid
A human ______ cell has 46 chromosomes, 23 chromosomes from each parent.
diploid
In Mendel's studies, a ______ trait is one that could mask the appearance of another trait.
dominant
The gametes of humans are called
eggs and sperm
The first cell of a new organism is formed from the merging of haploid gametes during
fertilization
The haploid cells of humans are called
gametes