Genetics topic 3

Question 1

Asexual Reproduction

Answer 1

Advantages:

No need to find a mate.
Rapid reproductive cycle.
Efficient in stable environments.

Disadvantages:

No variation in the population.
Less adaptability to changes in environment.

Question 2

Sexual Reproduction

Answer 2

Advantages:

Produces genetic variation in offspring.
Increases chances of survival in changing environments.

Disadvantages:

Requires finding a mate.
Slower reproduction process.

Question 3

Meiosis

Answer 3

Produces four daughter cells.
Each cell has half the number of chromosomes (haploid).
Results in genetically different gametes.

Question 4

Structure of DNA

Answer 4

DNA is a polymer made up of two strands coiled into a double helix.
Strands are linked by complementary base pairs (A-T, C-G) with hydrogen bonds.
Nucleotides consist of a sugar, phosphate group, and a base (A, T, C, G).

Question 5

Genome and Gene

Answer 5

Genome: The entire DNA of an organism.
Gene: A section of DNA that codes for a specific protein.

Question 6

Extracting DNA from Fruit

Answer 6

Steps:

Crush the fruit to break cell walls.
Add detergent to break down cell membranes.
Filter the mixture to remove large particles.
Add alcohol to precipitate DNA.

Question 7

DNA Bases and Proteins

Answer 7

The order of bases in DNA determines the order of amino acids in a protein.
Proteins fold into specific shapes, like enzymes.

Question 8

Protein Synthesis (Transcription and Translation)

Answer 8

1 RNA polymerase binds to non-coding DNA in front of a gene.
2 mRNA strand is produced from the coding DNA.
3 mRNA attaches to a ribosome.
4 Codons in mRNA code for specific amino acids.
5 tRNA transfers amino acids to the ribosome.
6 Amino acids link to form a polypeptide.

Question 9

Genetic Variants and Phenotype

Answer 9

Non-coding DNA variants can affect how much protein is produced.
Coding DNA variants can alter amino acid sequence, changing the protein’s activity.

Question 10

Alleles and Inherited Characteristics

Answer 10

Inherited characteristics differ due to different alleles of genes.
Dominant alleles mask recessive alleles in heterozygous individuals.

Question 11

Gregor Mendel and Genetics

Answer 11

Mendel discovered the principles of inheritance by studying pea plants.
His work was not understood until the discovery of DNA.

Question 12

Key Terms in Genetics

Answer 12

Chromosome: Structure of DNA.
Gene: Section of DNA.
Allele: Variant of a gene.
Dominant/Recessive: Type of allele.
Homozygous/Heterozygous: Identical/different alleles.
Genotype: Genetic makeup.
Phenotype: Physical characteristics.
Gamete: Sex cell (sperm/egg).
Zygote: Fertilized egg.

Question 13

Monohybrid Inheritance

Answer 13

Use Punnett squares to predict offspring traits.
Show the inheritance of dominant and recessive traits.

Question 14

Sex Determination

Answer 14

XX = female, XY = male.
Genetic diagrams can show how sex is determined.

Question 15

Monohybrid Cross Outcomes

Answer 15

Outcomes from monohybrid crosses can be analyzed using probabilities, ratios, and percentages.

Question 16

Sex-Linked Disorders

Answer 16

Sex-linked genetic disorders are often carried on the X chromosome.
Males are more likely to express these disorders (e.g., hemophilia).

Question 16

ABO Blood Groups Inheritance

Answer 16

Codominance occurs when both alleles contribute to the phenotype (e.g., blood type AB).
Multiple alleles include A, B, and O blood types.

Question 17

Causes of Variation

Answer 17

Genetic variation: Due to mutations and sexual reproduction.
Environmental variation: Caused by environmental factors (e.g., diet, climate).

Question 18

Effects of Mutations on Phenotype

Answer 18

Most mutations have no effect.
Some mutations have small effects, while rare mutations can have significant effects.

Question 18

Human Genome Project

Answer 18

Mapped the entire human genome.
Applications include personalized medicine and gene therapy.

Question 19

Genetic Variation

Answer 19

There is usually extensive genetic variation within a species.
Variations arise through mutations.

Question 20

Estimations

Answer 20

Use estimations to simplify complex calculations in genetics.
Example: Estimating the probability of offspring inheriting a trait.

Question 21

Numerical and Graphical Forms

Answer 21

Translate information between numerical and graphical forms.
Example: Use a graph to represent the proportion of offspring inheriting a trait from a Punnett square.

Question 22

Data Extraction from Graphs and Tables

Answer 22

Extract and interpret data from graphs, charts, and tables.
Example: Analyzing inheritance patterns or genetic variation from a data table.

Question 23

Direct Proportions and Ratios in Genetic Crosses

Answer 23

Use direct proportions and simple ratios in genetic crosses.
Example: In a monohybrid cross, the ratio of offspring traits may be 3:1 for dominant and recessive traits.

Question 24

Probability in Genetic Crosses

Answer 24

Use the concept of probability to predict outcomes of genetic crosses.
Example: Probability of inheriting a dominant or recessive allele

Question 25

Calculating Arithmetic Means

Answer 25

Calculate arithmetic means to determine the average outcome from multiple genetic crosses.
Example: Average percentage of offspring displaying a specific trait.

Question 26

Using Percentages in Genetic Analysis

Answer 26

Calculate percentage gain and loss of a particular genetic trait.
Example: Percentage of offspring with a specific phenotype from a Punnett square.

Question 27

Using Percentiles

Answer 27

Understand and use percentiles in monitoring growth or genetic traits.
Example: Comparing genetic trait distribution in a population using percentiles.