CHAPTER 3: The New Genetics Flashcards
No two cells of the human body contain exactly the same genetic instructions. TRUE or FALSE
TRUE
The genetic contribution of the father’s sperm determines whether a fertilized egg develops into a male or female. TRUE or FALSE
TRUE
Not all individuals are born genetically unique. TRUE or FALSE
FALSE
Humans have more than 100,000 genes. TRUE or FALSE
FALSE
All the genes a person has show up as observable characteristics. TRUE or FALSE
FALSE
The genomes of humans and chimpanzees are 99 percent identical. TRUE or FALSE
TRUE
There is a single alcoholism gene. TRUE or FALSE
FALSE
Middle-aged couples are less likely than younger couples to produce a child with a chromosomal abnormality. TRUE or FALSE
FALSE
Everyone carries several genes that could produce serious diseases or disabilities in their offspring. TRUE or FALSE
TRUE
Most known genetic disorders are transmitted through recessive genes. TRUE or FALSE
FALSE
Definition of genetic code?
molecular beginnings of human development
What is Deoxyribonucleic Acid (DNA)?
the chemical composition of the molecules that contain genes
What is chromosome?
one of 46 molecules of DNA (in 23 pairs) that virtually each cell of the human body contains and that, together, contain all the genes. Other species have more or fewer chromosomes
Definition of gene:
the basic unit for the transmission of heredity
Definition of zygote:
Two gametes (sperm and ovum) combine and produce a new individual with 23 chromosomes from each parent.
Definition of Gametes:
Reproductive cells
sperm and ova
Each gamete consists of how many chromosomes?
Each gamete consists of 23 chromosomes.
Even a small difference in one gene can cause major changes in a person’s….
A) genotype
B) phenotype
B) phenotype
Definition of genome:
Involves the full set of genes that are the instructions to make an individual member of a certain species
deifnion of Allele:
Variation of a gene or any of the possible forms in which a gene for a particular trait can occur
Single-nucleotide polymorphisms (SNP)
How many copies of each gene do humans get?
2 copies, on from each parent
Do the 2 copies of genes have to be identical with we get them?
no
Each variation of a gene is called an?
allele
How many chromosomes do humans usually possess?
46 chromosomes
Definition of phenotype:
The observable characteristics of a person.
Definition of genotype:
Organism’s entire genetic inheritance, or
genetic potential
Definition of homozygous:
Two genes of one pair that are exactly the
same in every letter of their code
Definition of heterozygous:
Two genes of one pair that differ in some way
How many chromosomes and genes do people have?
23 Pairs of chromosomes and about 20,000 genes.
What is an allele?
It is a variation that makes a gene different in some way from other genes for the same characteristic.
Why is each zygote unique, genetically?
When a sperm and an ovum combine, the zygote created is a new cell in which the genes on one of eight million possible sperm from the father interact with the genes on one of the eight million possible ova from the mother.
What determines whether a baby is a boy or a girl?
The sex depends on which sperm penetrates the ovum –a Y sperm, creating a boy (XY) or an X sperm, creating a girl (XX).
How are new cells (new people) formed?
The zygote begins duplication and division, and then differentiation and specialization occur.
Cells change from being stem cells, those from which any other specialized type of cell can form, to being only one kind of cell.
How many cells does a newborn have?
26 billion cells.
Each cell carries complete copy of genetic instructions
What are Stem Cells?
- Are first cells
- Are able to produce any other cell
- Can be reprogrammed
Definition of Assisted Reproductive Technology (ART):
General term for the techniques designed to help infertile couples conceive and sustain a pregnancy
What is In Vitro Fertilisation (IVF):
– Involves fertilization that takes place outside a woman’s body
– Involves mixing sperm with surgically removed ova from the woman’s ovary and implanting zygote into a woman’s uterus
There are two types of twins, what are they?
- monozygotic (identical) twins
- dizygotic (fraternal) twins
What are Monozygotic twins?
– Identical
– Originate from one zygote that splits apart very early in development
– Incomplete split results in conjoined twins.
– Same genotype but slight variations in phenotype are possible due to environmental influences.
What are Dizygotic twins?
– fraternal
– Result from fertilization of two separate ova by two separate sperm
– Dizygotic twins have half their genes in common and occur twice as often as monozygotic twins.
– Incidence is genetic and varies by ethnicity and age.