Biology Honors Final Study Flashcards

Biology Honors Final Exam Flashcards

Define the cell cycle.

A series of events that take place in a cell leading to its division and duplication.

What is the correct order of the phases of the cell cycle?

Interphase → Prophase → Metaphase → Anaphase → Telophase → Cytokinesis

Describe the process of mitosis and meiosis. What are the similarities and differences?

Mitosis: 1 division → 2 identical diploid cells. Meiosis: 2 divisions → 4 different haploid cells. Both involve cell division and share phases like prophase, metaphase, etc.

Asexual reproduction is more similar to mitosis or meiosis?

Mitosis

In animals, when does meiosis occur?

During the production of gametes (sperm and egg).

What is crossing over in meiosis?

Exchange of genetic material between homologous chromosomes during Prophase I, increases genetic diversity.

What is a karyotype?

A visual profile of all the chromosomes in a cell. Used to detect abnormalities and determine sex.

The codon of and the anticodon of are complementary.

mRNA, tRNA

What do the rungs of a DNA ladder represent?

Paired nitrogenous bases (A-T and G-C) connected by hydrogen bonds.

DNA is found in what part of the cell?

The nucleus.

What components make up a nucleotide?

Phosphate group, deoxyribose sugar, nitrogenous base.

Which of the following represent a difference between DNA and RNA?

DNA: double-stranded, deoxyribose, thymine. RNA: single-stranded, ribose, uracil.

Order DNA, nucleus, chromosome, nucleotide, nitrogenous base from largest to smallest.

Nucleus > Chromosome > DNA > Nucleotide > Nitrogenous base

The code of mRNA is directly dependent on what?

The sequence of bases on the DNA template strand.

Which of the following does NOT happen in protein synthesis? a. tRNA and mRNA complement at ribosome b. DNA replicates c. mRNA is synthesized d. tRNA bonds with an amino acid

b. DNA replicates

What is the complementary DNA strand for TAC GTC GTA GGT AGT?

ATG CAG CAT CCA TCA

Translate DNA strand TAC GTC GTA GGT AGT to amino acids using mRNA codons.

Start → Val → His → Pro → Ser

Which letter in a diagram represents transcription? Which one translation?

Transcription = DNA → mRNA, Translation = mRNA → Protein

Correct order of stages: 1. tRNA brings amino acids, 2. DNA template for mRNA, 3. mRNA moves to ribosome, 4. Amino acid chain forms?

2 → 3 → 1 → 4

Genetic makeup of an organism is referred to as?

Genotype

Cross of two heterozygous purple pea plants: frequency of white offspring?

25%

Which molecule contains the anticodon and transports amino acid?

tRNA

Enzyme used in transcription?

RNA Polymerase

Where does translation occur?

At the ribosome

If 50% of guinea pig offspring are black and 50% are white, parent genotypes are?

Bb and bb

Genotype ratio of AaBb x aabb?

1 AaBb : 1 Aabb : 1 aaBb : 1 aabb

Homozygous black dog x homozygous white dog → gray F1; What color will F2 be when two gray dogs are crossed?

25% black, 50% gray, 25% white (incomplete dominance)

Possible genotypes for blood types A, B, AB, and O?

A: AA or AO, B: BB or BO, AB: AB, O: OO

What is an allele?

Different versions of a gene.

Chromosomes that are same size, shape and gene info are called?

Homologous chromosomes

When are two organisms considered same species?

When they can reproduce and produce fertile offspring.

Define natural selection and give an example.

Process where organisms with advantageous traits survive and reproduce. E.g., darker moths surviving better in polluted environments.

List 5 factors that change gene pools.

Mutation, natural selection, genetic drift, gene flow, non-random mating.

Define gene pool.

Total set of genes in a population.

Define biological fitness.

Ability of an organism to survive and reproduce.

Define artificial selection.

Selective breeding by humans for desired traits.

If 20% of insects are brown (recessive), what percent is heterozygous? (Hardy-Weinberg)

q = 0.45, p = 0.55 → 2pq = ~49.5% heterozygous

What is the function of the centrioles during mitosis?

Centrioles help organize the mitotic spindle and pull chromosomes apart during cell division.

What is the tRNA anticodon for CGA?

The tRNA anticodon that pairs with CGA (mRNA codon) is GCU.

Define haploid and give examples.

Haploid cells contain one set of chromosomes. Examples: gametes (sperm, egg), cells undergoing meiosis.

Define diploid and give examples.

Diploid cells contain two sets of chromosomes. Examples: somatic cells, zygotes, stem cells.

What happens during Prophase?

Chromatin condenses into chromosomes, nuclear envelope breaks down, spindle fibers form from centrioles.

What happens during Metaphase?

Chromosomes align in the middle of the cell along the metaphase plate, attached to spindle fibers.

What happens during Anaphase?

Sister chromatids are pulled apart toward opposite poles of the cell.

What happens during Telophase?

Nuclear envelope re-forms, chromosomes uncoil back to chromatin, cell prepares for cytokinesis.

Define mutation. How can it affect a gene?

A mutation is a change in DNA sequence. It can be silent, harmful, or beneficial depending on its location and type.

What is transcription and where does it occur?

Process of copying DNA to mRNA. Occurs in the nucleus.

What is translation and where does it occur?

Process where ribosome reads mRNA to assemble a protein. Occurs in the cytoplasm at the ribosome.

What is DNA replication and when does it occur?

The process of copying DNA. Occurs during the S phase of interphase.

What are codons and what do they code for?

Codons are sequences of three mRNA bases that code for specific amino acids.

What is codominance? Give an example.

Both alleles are fully expressed. Example: AB blood type.

What are the four blood types and their genotypes?

Type A: AA or AO; Type B: BB or BO; Type AB: AB; Type O: OO.

What is incomplete dominance? Give an example.

Neither allele is fully dominant; heterozygote shows a blend. Example: red + white flower → pink flower.

What are linked traits?

Genes located close together on the same chromosome and inherited together.

How can you tell the sex of a person from a karyotype?

Presence of XX = female, XY = male.

How does UV radiation affect skin?

It increases melanin production as a protective response, darkening the skin.

What is lactic acid and when is it produced?

Lactic acid is produced in muscle cells when oxygen is low during anaerobic respiration.

What connects muscles to bones?

Tendons.

What connects bones to other bones?

Ligaments.

How are X-linked traits passed down?

Males inherit X-linked traits from their mothers. Females must inherit two copies to express a recessive trait.

What is the purpose of a pedigree chart?

To trace inheritance of traits through generations and identify carriers or affected individuals.

What is the role of tRNA in protein synthesis?

tRNA brings specific amino acids to the ribosome, matching its anticodon to the codon on mRNA.

What is biotechnology and give an example?

Use of living systems to develop technologies. Example: Genetic engineering, CRISPR, cloning, DNA fingerprinting.

What is nondisjunction and what does it cause?

Failure of chromosomes to separate properly during meiosis. Causes conditions like Down Syndrome (trisomy).

What is a gene?

A segment of DNA that codes for a protein or trait.

What is natural selection?

Process by which organisms with favorable traits survive and reproduce more successfully.

Define artificial selection.

Selective breeding by humans to produce desired traits in organisms.

What is the role of skin in thermoregulation?

Releases sweat to cool the body; blood vessels constrict or dilate to conserve or release heat.

What are the parts of a nucleotide?

Phosphate group, five-carbon sugar (deoxyribose or ribose), nitrogen base.

How do red blood cells carry oxygen?

They contain hemoglobin, a protein that binds to oxygen.

What causes anemia?

Lack of iron or hemoglobin in the blood, reducing oxygen-carrying capacity.

What are homologous chromosomes?

Chromosome pairs (one from each parent) that have the same genes in the same order, but may have different alleles.

What is biological fitness?

The ability of an organism to survive and reproduce in its environment.

What happens during cytokinesis?

The cell's cytoplasm divides, forming two new cells after mitosis or meiosis.