3b- Inheritence Flashcards
What is inheritance?
Inheritance is the process by which genetic information is passed from parents to offspring through DNA.
What is the structure of DNA?A:
DNA is a double helix made of two strands connected by base pairs (Adenine-Thymine, Cytosine-Guanine). Each strand is made of nucleotides containing a sugar, phosphate, and base.
What are genes and chromosomes?
Genes: Sections of DNA that code for specific proteins, determining traits.
Chromosomes: Structures made of DNA, found in the nucleus. Humans have 46 chromosomes (23 pairs).
What is the difference between genotype and phenotype?A:
Genotype: The genetic makeup of an organism (e.g., Bb for eye color).
Phenotype: The physical expression of a trait (e.g., brown eyes).
What is the difference between dominant and recessive alleles?
Dominant Allele: Expressed even if only one copy is present (represented as uppercase, e.g., B).
Recessive Allele: Expressed only if two copies are present (represented as lowercase, e.g., b).
What is a homozygous and heterozygous genotype?A:
Homozygous: Two identical alleles (e.g., BB or bb).
Heterozygous: Two different alleles (e.g., Bb).
How is sex determined in humans?
Sex is determined by the 23rd pair of chromosomes:
XX: Female
XY: Male
What is a Punnett square and how is it used?
A Punnett square predicts the probability of offspring inheriting particular traits by combining parental alleles.
Practical Investigating Genetic Crosses Using a Punnett Square
Example: Eye Color Cross (B = Brown, b = Blue)
Cross: Bb × Bb
Punnett Square:
Results:
Phenotype Ratio: 3 brown : 1 blue
Genotype Ratio: 1 BB : 2 Bb : 1 bb
What are mutations and how do they affect organisms?
Mutations are changes in the DNA sequence that can lead to different proteins. They may be beneficial, harmful, or have no effect.
What is inheritance?
Inheritance is the transmission of genetic information from parents to offspring via DNA. This process ensures that characteristics, such as eye color or blood type, are passed from one generation to the next.
What is the structure of DNA, and why is it important?
DNA (Deoxyribonucleic acid) is a double helix composed of two strands twisted around each other, held together by complementary base pairs:
Adenine (A) pairs with Thymine (T)
Cytosine (C) pairs with Guanine (G)Each nucleotide consists of a sugar (deoxyribose), a phosphate group, and a nitrogenous base. The sequence of bases determines the genetic code, which instructs cells on how to build proteins.
what are Genes:
Segments of DNA that contain the instructions for making specific proteins, which determine an organism’s traits.
what is Chromosomes:
Long strands of DNA coiled up inside the nucleus of a cell. Humans have 23 pairs of chromosomes (46 total), including one pair that determines sex.
define Genotype:
The genetic makeup of an organism (e.g., Bb for eye color).
define Phenotype:
The physical expression of the genotype (e.g., brown eyes)
what is Dominant Allele:
Expressed when present (represented as uppercase, e.g., B for brown eyes).
what is Recessive Allele:
Only expressed when two copies are present (represented as lowercase, e.g., b for blue eyes).
What is Homozygous:
Having two identical alleles for a trait (e.g., BB or bb).
what is Heterozygous:
Having two different alleles for a trait (e.g., Bb).
How is sex determined in humans?A:
Human sex is determined by the 23rd pair of chromosomes:
XX: Female
XY: MaleThe father determines the sex, as he can contribute either an X or a Y chromosome.
What is a Punnett square, and how is it used in genetic crosses?A:
A Punnett square is a diagram used to predict the possible genetic outcomes of a cross between two individuals. It shows the probability of inheriting particular alleles.
What are mutations, and how do they impact organisms?
A: Mutations are changes in the DNA sequence that can result in different proteins being produced. They can be:
Beneficial: Provide advantages, such as resistance to diseases.
Neutral: No significant effect on the organism.
Harmful: Lead to genetic disorders like sickle cell anemia or cystic fibrosis.
