Review Key Day 2
Cell Division and Genetics
1.The DNA must replicate before mitosis in order to have two identical sets of DNA, one for each daughter cell
2.The cell will complete mitosis when making ____somatic/body/diploid____ cells.
3.The cell will complete meiosis when making __gamete/sex/haploid_ cells.
4. List four differences between mitosis and meiosis:
1.
2.
3.
4.
Mitosis creates diploid cells while meiosis creates haploid cells
Mitosis creates genetically identical cells while meiosis creates genetically unique cells
Mitosis is used for growth, repair and healing while meiosis creates sex cells
Meiosis is two sets of divisions while mitosis is one set of divisions
5. Summarize how sexual reproduction, which includes meiosis and fertilization, affects genetic variation within an
offspring. Meiosis makes genetically different gametes because crossing-over occurs. When fertilization occurs, a
genetically unique egg cell is fused with a genetically unique sperm cell to create a unique zygote
6. Mitosis phases
Phase
What happens in the phase
Interphase
“I’m working” – cell does its jobs like making proteins, repairing organelles, and growing
Prophase
Metaphase
“Pieces of DNA” – DNA coils into chromosomes to prepare for cell division/nucleus
disappears
“Middle” – Chromosomes line up at the middle of the cell
Anaphase
“Away” – Chromosomes are pulled away from one another
Telophase
“Twin Nuclei form” – the nuclei reform around the separated sets of DNA
9. What are the three components of a nucleotide?
1 sugar + 1 phosphate + 1 base
10. Draw a picture of the structure of DNA that (at least) includes the terms: base, 1 sugar, phosphate, nucleotide,
and helix.
11. Describe gel electrophoresis using the following terms: electrophoresis, agarose gel, DNA bands, banding
pattern, lane, DNA fragment, common ancestry, relatedness
Gel electrophoresis separates DNA fragments using electricity. DNA fragments move through an agarose gel
and banding patterns are viewed to see relatedness between individuals. Common ancestry, paternity, and
crime scene evidence can all be determined using gel electrophoresis.
12. What do the bands in the gel pattern represent? What causes some bands to move further than other?
DNA segments – short DNA segments move further than long segments because they fit easily through the
agarose gel
13. RNA/ DNA Comparison: Fill in the chart
Characteristic
DNA
Sugar present
Deoxyribose
RNA
Ribose
Number of strands
2
1
Location(s) It Can
Be Found
Nucleus of eukaryotes/cytoplasm of prokaryotes as
a nucleoid
Nucleus or cytoplasm
Used in ribosomes
Function(s)
Holds all genetic information for an organism
Helps create a protein from a gene
sequence
13. Mutations: Mutations and crossovers create different genes and gene sequences. Explain how mutations are
an important and normal part of sexual reproduction.
Crossing-over during meiosis 1 swaps genes on DNA to create variation in the gametes. This helps ensure that all
offspring will be genetically different from their parents and from one another
14. Protein Synthesis Definitions
Word
Definition/Picture
Codon
Series of 3 bases on messenger RNA – each codon indicates 1 amino acid needed to build
a protein
Nucleotide
1 sugar + 1 phosphate + 1 base/building blocks of DNA and RNA
Replication
Copying an identical strand of DNA – occurs in the nucleus before mitosis and meiosis
(REMEMBER: Crossing over during meiosis changes the DNA in each gamete!!!)
Anticodon
A 3 base sequence on tRNA that is the opposite of a codon
Clone
genetically identical offspring
mRNA
Messenger RNA – carries the copied DNA information to make a protein
tRNA
Transfer RNA – brings amino acids to ribosomes in order to build a protein
15.What happens during transcription? DNA information to make a protein (1 gene) is copied on to mRNA in the
nucleus
16.What happens during translation? mRNA brings the gene information to the ribosome. At the ribosome, mRNA is
read one codon at a time so that tRNA can bring the correct amino acid sequence to form a protein
17. What is a chain of amino acids called? protein
18.Genetics Definitions
Word
Definition
Allele
Any variation on a trait, written as a letter
Autosome
A body chromosome/identical in males and females/humans have 22 pairs of autosomes
Dominant
An allele that is the phenotype when one or two copies are present
Gene
Genotype
DNA information to produce a protein
The two letter genetic sequence for a trait
Heterozygous
Aa – dominant trait expressed
Homozygous
AA or aa – having two identical alleles for a given trait
Phenotype
The physical appearance of an organism
Recessive
Lowercase letter, the allele the is expressed only when an individual is homozygous recessive
for a trait
Females – XX males – XY
Sex-chromosome
Complete the following punnett squares. Give the genotype and phenotype of each.
19. Monohybrid
20. Sex-linked
Cross a heterozygous right handed person with a left handed person.
Right is dominant over left.
Cross a female who is a carrier for hemophilia with a hemophiliac male.
21.Answer the following questions.
In Pisum sativum, a pea plant, the allele for purple flower (P) is dominant over the allele for white flowers (p). A
cross between two purple-flowered plants in both purple-flowered and white-flowered offspring, as shown in the
table below.
RESULTS OF PEA PLANT CROSS
Flower
Number of
Plants
Purple
103
White
35
On a piece of paper, do the following:
Draw a Punnett Square that shows the cross between the two purple-flowered parent plants described
above. When writing the allele pairings, underline all lowercase letters (p).
Fill in the genotypes of the offspring on the Punnett Square.
Make a key to indicate which genotype produces which flower color.
Give the ratio of flower colors that can be expected from the cross.
Explain how the data in the table and in the Punnett square helped you determine the ratio.
22. A genetics study was conducted that crossed two red-flowered plants. The next generation was a mixture of redflowered and white-flowered offspring. Which of these represents those of the parent generation?
A) rr and rr
B) Rr and Rr C) RR and rr D) RR and RR