Download Concept 3 - Ms DeBeaudrap Science

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Science 9
Unit A – Biological Diversity
Vocabulary Terms Concept 3
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genetics
continuous variation
discrete variation
dominant trait
recessive trait
mutation
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mutagen
DNA
chromosome
allele
gene
Concept 3 – Genetics
Learning Concept
 Describe, in general terms, the role and relationship of chromosomes,
genes and DNA
 There is a ________________ for each _________________
_______________ found within all the cells of the body
 Known as ________________________________, or _____________
 ________________ material responsible for variation
 First identified in ________________
 In 1953 a scientific paper by ________________________________ and
________________________________ presented the ________________
of DNA
 ________________________________ had groundbreaking work in
discovering the ________________ of DNA
 Structure is a ________________________________
 Resembles a ________________ that has been twisted into a spiral
 Rungs of the ladder are different in their composition
 Found in ________________
 ________________ (A) and ________________ (T)
 ________________ (G) and ________________ (C)
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 The ________________ of these four chemicals create a
________________ that cells can read
 Read in ________________
 Refer to this as the ________________________________ – a
language the cell understands
 These chemicals are _____________________________________
___________ on Earth
 ________________ are packages within the cell which contain the
_________
 ________________ chromosome only contains some of the
instructions for making an organism
 These are ________________ within a cell
 In plants and animals, chromosomes are contained within the
________________________________________________
 Chromosome ________________________________ from species to
species
 The ________________ of the chromosomes also varies
 Currently accepted in the scientific world
 ________________ are responsible __________________________
______________________________________
 A ________________________________ is an ________________
________________________________, with coded instructions
 ________________ are located on ________________
 ________________ have numerous ___________________________
 Genes come in ________________
 ________________ genes carry ________________ for the same
thing
 The same genes occupy ________________________________ on
the chromosomes
 The DNA code may differ in each location
 There
are
________________________________
of
the
________________ coming from the ________________
 These different gene forms are called ________________
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Formative Assessment
1. Define the term DNA and explain its function, in your own words.
 deoxyribonucleic acid
 blueprint of life for each multicellular organism
 tells the cell what to do and what to form where
2. What is a chromosome? Explain its function.
 a structure in which DNA is arranged and along which genes are found
3. What is an allele? Explain its function.
 a possible form of a gene
 variations arise from alleles, if environment changes then some of the
species will survive
4. Using the following mind map, provide linking statements to explain the
relationships. What is their role in storing genetic information?
DNA
CHROMOSOMES
GENES
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Learning Concept
 Distinguish between:
 Cell division that leads to identical daughter cells
 Cell division that leads to formation of sex cells
 Describe, in general terms, the synthesis of genetic material that takes
place during fertilization
 ________________ reproduction produces offspring ________________
________________ to the parents
 ________________ reproduction produces offspring ________________
________________ from the parents
 ___________________________ occurs in ________________ organisms
 Examples: amoeba, paramecium
 Cell contents divided ________________between the two new cells
 What happens if the DNA is split between the two cells?
 How is this corrected?
 Parent cell first makes an _____________________
__________________________
 For a short time, the parent cell has two
copies of its DNA
 When the cell divides, each new cell gets
_____________________________________
_____________________________________
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 A ________________ process occurs in multicellular organisms – called
________________
 Two new cells are produced with the same number of
________________
 Occurs on the ________________
 Responsible for ________________ and ________________ in
multicellular organisms
 Sexual reproduction requires the ________________________________
 The ________________ cell
 The ________________ cell
 Using humans as an example,
 What happens if each gamete contained 23 pairs of chromosomes?
 ________________________________________________________
________________________________________________________
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 ________________ is a type of cell division that produces cells with only
________________________________ of a normal cell
 A ________________ cell will have ________________ the DNA
 An ________________ cell will have ________________ the DNA
 When the ________________ to form the ________________, it will
have a ________________________________ of DNA
 ________________ involves ________________________________ to
produce ________________________________
 A gamete will contain one copy of each different chromosome
Science Log
Organism
Cabbage
Black
Bear
Human
Peanut
#
#
#
#
# of pairs of
Chromosomes Chromosomes Chromosomes Chromosomes
Chromosomes
after Mitosis in a body cell
in a Gamete
in a Zygote
18
38
23
40
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Formative Assessment
1. Describe a type of cell division that occurs during the asexual reproduction
of a unicellular organism.
2. What type of cell division is required for sexual reproduction? How does it
differ from cell division during asexual reproduction?
3. Describe the type of cell division that occurs in the body cells (ex skin) of
multi-cellular organisms.
4. If the amount of DNA in a gamete of an organism is n, is the amount of DNA
in the body cells of the organism equal to ½n, n, or 2n? Explain.
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 Plant and animal breeders have been conducting experiments in
________________________________________________ for a long
period of time
 Only organisms with ________________________________ were
allowed to reproduce
 Certain ________________________________________________
were eventually detected
Learning Concept
 Identify examples of dominant and recessive characteristics
 Recognize dominance and recessiveness provides only a partial explanation
for the variation of characteristics in offspring
 ________________ looks at how ________________________________
are passed from one generation to the next
 Work was began by ________________________________, an
Austrian monk
 Traced patterns of inheritance in ________________
 Discovered fundamental principles that led to modern genetics
 A ________________ organism (plant or animal) is one whose ancestors
________________________________________________
 A ________________ organism (plant or animal) is one who was produced
from ________________________________ with a ________________
________________________________________________
 ________________ traits are those which are typically ________________
________________________________ if ________________ is present
 ________________ dominant alleles are inherited
 Example
 Female provided allele for Yellow seed (dominant)
 Male provided allele for Yellow seed (dominant)
 Offspring will inherit both alleles
 Two dominant alleles are inherited and yellow seeds will
be observed
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 ________________________________ alleles are inherited
 Example
 Female provided allele for Tall plants (dominant)
 Male provided allele for Dwarf plants (recessive)
 Offspring will inherit both alleles
 Tall is a dominant alleles, so while both alleles are
inherited, a TALL plant will be observed
 ________________ traits are those which are _____________________
_____________________________________ when ________________are
present
 ________________________________ alleles are inherited
 Example:
 Female provided allele for white flowers
 Male provided allele for white flowers
 Offspring will inherit both alleles
 Two recessive alleles are inherited and a white flower
will be observed
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Science Log
 Which of the examples listed in these notes (seed color, tall/dwarf plants,
flower color) represents
 A hybrid?
 A purebred?
Learning Concept
 Investigate the transmission of characteristics from parents to offspring,
and identify examples of characteristics in offspring that are:
 The same as the characteristics of both parents
 The same as the characteristics of one parent
 Intermediate between parent characteristics
 Different from both parents
 Recall that each ________________ has a _____________________
_____________________, and ________________ are ________________
________________ carried on those chromosomes
 There is written “code” for genetics to show dominant versus
recessive traits
 We call the ________________________________ the organism’s
________________
 ________________ traits are always written as the ________________
 ________________ traits are always written as the __________________
______________
 For yellow seeds
 Dominant trait for yellow could be _______
 Recessive trait for green will then be _______
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 A pea plant with the yellow seed color will have two alleles
 Dominant traits are expressed when:
 Two ________________ alleles are inherited
 Two ________________________________ alleles
inherited
 What are the two possible genotypes for this pea plant?
are
 A pea plant with the green seed color will also have two alleles
 Recessive traits are expressed when:
 Two ________________ alleles are inherited
 What is the one possible genotypes for this pea plant?
Science Log
 Why is it possible for two plants that express the dominant yellow seed
color to have one green seed offspring?
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Science Log
 Textbook Challenge: Exploring Genetic Possibilities pg 52
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 Other patterns of inheritance also exist, due to
 ________________________________
 ________________________________ of inheritance
 ________________ factors
 ________________________________ arises when traits are not truly
dominant or recessive
 A purebred red snapdragon, when crossed with a purebred white
snapdragon, will produce all pink offspring
 What is the genotype of the red snapdragon?
 What is the genotype of the white snapdragon?
 What is the genotype of the pink snapdragon?
 ________________________________________________
can
cause
variations in things such as height, weight, etc.
 Presence of environmental factors can ________________ the genes
 Consumption of ________________ during a pregnancy will
interfere with normal development of _________________
_______________________________________________
 ________________ can cause ________________ deformities
 Example: thalidomide in the late 1950s
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Formative Assessment
1. Explain how dominant and recessive traits differ from one another.
2. How does a purebred individual differ from a hybrid individual?
3. How could two black cats produce a kitten who has white fur? Use a
diagram or Punnett square to explain your answer.
4. If you wanted to be certain a trait would appear in the offspring of the
plants or animals that you were breeding, what would you have to find out
about the parents? Explain.
5. Can dominance or recessiveness explain why two cats from the same litter
have different masses or have different leg lengths? Explain your answer.