Bio 101 Unit 3 Test

What are the major components of the nucleotides that make up DNA?

A phosphate group, a deoxyribose sugar, and a nitrogenous base (A, T, C, or G).

What are the major components of the nucleotides that make up RNA?

A phosphate group, a ribose sugar, and a nitrogenous base (A, U, C, or G).

What are the complementary base pairs in DNA?

Adenine (A) pairs with Thymine (T), and Cytosine (C) pairs with Guanine (G).

What are the complementary base pairs in RNA?

Adenine (A) pairs with Uracil (U), and Cytosine (C) pairs with Guanine (G).

What kinds of bonds hold the two strands of DNA together?

Hydrogen bonds.

What makes up the backbone of DNA?

Alternating phosphate groups and deoxyribose sugars.

What are the differences between RNA and DNA?

RNA has ribose sugar, uracil instead of thymine, and is usually single-stranded. DNA has deoxyribose sugar, thymine, and is double-stranded.

What are some similarities between RNA and DNA?

Both are nucleic acids, both have phosphate backbones, and both use adenine, cytosine, and guanine.

Describe DNA’s shape.

Double helix (twisted ladder).

Describe RNA’s shape.

Usually single-stranded, but can form secondary structures like hairpins.

What does mRNA do?

Carries the genetic information from DNA to the ribosome for protein synthesis.

What does tRNA do?

Transfers amino acids to the ribosome during translation, based on the mRNA codon.

What does rRNA do?

Forms the core of the ribosome and catalyzes protein synthesis.

Describe the process of DNA replication.

DNA unwinds, and each strand serves as a template for a new complementary strand, resulting in two identical DNA molecules.

Describe the process of transcription.

DNA is transcribed into mRNA by RNA polymerase, using one DNA strand as a template.

Describe the process of translation.

mRNA is read by ribosomes, and tRNA brings amino acids to build a polypeptide chain based on the mRNA codons.

How do you use a codon chart to determine the amino acid?

Match the mRNA codon (3 nucleotides) to the corresponding amino acid on the chart.

If given a strand of DNA, how do you find the complementary strand?

Replace A with T, T with A, C with G, and G with C.

If given a strand of DNA, how do you find the mRNA strand?

Replace T with U, and keep A, C, and G the same.

If given mRNA codons, how do you find the tRNA anticodons?

The tRNA anticodon is complementary to the mRNA codon (A-U, C-G).

How is cell division different in prokaryotes vs. eukaryotes?

Prokaryotes use binary fission; eukaryotes use mitosis or meiosis.

What happens during Interphase?

The cell grows, replicates its DNA, and prepares for division.

What happens in each phase of mitosis (PMAT)?

Prophase: Chromosomes condense, nuclear envelope breaks down. Metaphase: Chromosomes line up at the metaphase plate. Anaphase: Sister chromatids separate and move to opposite poles. Telophase: Chromosomes de-condense, nuclear envelope reforms.

What are the phases of mitosis in order?

Prophase, Metaphase, Anaphase, Telophase (PMAT).

What happens in each phase of meiosis?

Meiosis I: Homologous chromosomes separate. Meiosis II: Sister chromatids separate.

What are the phases of meiosis in order?

Prophase I, Metaphase I, Anaphase I, Telophase I, Prophase II, Metaphase II, Anaphase II, Telophase II.

What are the differences between mitosis and meiosis?

Mitosis produces 2 diploid cells; meiosis produces 4 haploid cells. Mitosis is for growth/repair; meiosis is for sexual reproduction.

What is the difference in products between male and female meiosis?

Males produce 4 sperm cells; females produce 1 egg and 3 polar bodies.

What is mitosis used for?

Growth, repair, and asexual reproduction.

What is meiosis used for?

Producing gametes for sexual reproduction.

What is the difference between asexual and sexual reproduction?

Asexual involves one parent and produces genetically identical offspring; sexual involves two parents and produces genetically diverse offspring.

How many chromosomes do humans have?

46 (23 pairs).

How many chromosomes are in human gametes (sperm/egg)?

23 (haploid).

What is one difference between plant and animal mitosis?

In plants, a cell plate forms during cytokinesis; in animals, a cleavage furrow forms.

How do the cells produced by mitosis compare to the original cell?

They are genetically identical and have the same amount of DNA.

How do the cells produced by meiosis compare to the original cell?

They are genetically different and have half the amount of DNA (haploid).

What is the function of the spindle?

To separate chromosomes during cell division.

What is cytokinesis?

The division of the cytoplasm to form two separate daughter cells.

What is a dominant allele?

An allele that is expressed even if only one copy is present.

What is a recessive allele?

An allele that is only expressed if two copies are present.

What is homozygous?

Having two identical alleles for a gene (e.g., AA or aa).

What is heterozygous?

Having two different alleles for a gene (e.g., Aa).

What is a genotype?

The genetic makeup of an organism (e.g., AA, Aa, aa).

What is a phenotype?

The physical expression of a genotype (e.g., brown eyes).

What is an allele?

A variant form of a gene.

What is a pedigree chart?

A diagram that shows the inheritance of a trait across generations.

What is a karyotype?

A visual representation of an individual’s chromosomes.

How do you work a simple dominance Punnett square?

Cross two heterozygous parents (Aa x Aa) to predict offspring genotypes and phenotypes.

How do you work an incomplete dominance Punnett square?

Cross two heterozygous parents (Aa x Aa), where the heterozygous phenotype is a blend of the two homozygous phenotypes.

How do you work a sex-linked Punnett square?

Use X and Y chromosomes to predict inheritance of traits linked to sex chromosomes (e.g., color blindness).

How do you work a codominance Punnett square?

Cross two heterozygous parents (Aa x Aa), where both alleles are expressed equally in the phenotype (e.g., blood type AB).

How do you work a blood type Punnett square?

Use multiple alleles (A, B, O) to predict blood type inheritance.

What sex chromosomes are associated with a male?

XY.

What sex chromosomes are associated with a female?

XX.

What is meant by multiple alleles?

A gene that has more than two possible alleles (e.g., blood type has A, B, and O).

How can the environment affect phenotype?

Factors like diet, temperature, and chemicals can influence gene expression (e.g., fur color in Himalayan rabbits).

What is a mutation?

A change in the DNA sequence.

What is a deletion mutation?

When one or more nucleotides are removed from the DNA sequence.

What is an insertion mutation?

When one or more nucleotides are added to the DNA sequence.

What is a point mutation (base substitution)?

When one nucleotide is replaced by another.

What is a translocation mutation?

When a segment of DNA is moved to a different location.

What is a duplication mutation?

When a segment of DNA is copied and inserted elsewhere.

When can mutations happen?

During DNA replication, exposure to mutagens, or errors in repair mechanisms.

When do mutations get passed on to offspring?

If they occur in gametes (sperm or egg).

What are some benefits of mutations?

They can lead to genetic diversity and adaptation (e.g., antibiotic resistance).

What are some disadvantages of mutations?

They can cause diseases (e.g., cancer) or harmful genetic disorders.