Grade 11 Biology unit 2

Flash cards - test review questions

Question

Answer

Define genetics.

Genetics is the study of how traits are passed from parents to offspring through genes.

How many chromosomes are present in each human body cell?

46 chromosomes (23 pairs)

What different forms can chromosomes take on during the cell cycle?

Chromatin, chromosomes, sister chromatids

Define chromatin, chromosome, sister chromatids, centromere and telomere.

Chromatin: Loose, thread-like DNA in the nucleus when the cell isn’t dividing; Chromosome: Tightly coiled DNA formed from chromatin; carries genetic information; Sister chromatids: Two identical copies of a chromosome, joined together before cell division; Centromere: The pinched spot that holds sister chromatids together; Telomere: Protective ends of a chromosome, like tips on shoelaces; they shorten with age

Know how to label these terms if given an image.

Refer to diagram with labels: chromatin, chromosome, sister chromatids, centromere, telomere

Define genes, locus and genome.

Gene: Part of a chromosome made of DNA; determines your traits; Locus: The physical location on a chromosome where a gene is located; Genome: Full set of genetic information

What is DNA? What does it stand for? Where is DNA found within our cells?

DNA is the molecule that carries genetic information in living organisms. DNA stands for Deoxyribonucleic Acid. DNA is found in the nucleus of a cell.

Which scientists played important roles in the discovery of the DNA molecule structure?

Friedrich Miescher discovered nuclein (early name for DNA); Hammerling’s experiments showed that DNA is in the nucleus and controls growth

How many strands does DNA have? What is the building block of DNA? What 3 components make up a nucleotide?

DNA has 2 strands. Building block: nucleotide. Each nucleotide is made of: phosphate group, sugar, nitrogen base

How many types of nitrogenous bases are found in DNA? What are the names of these bases?

Four types: Adenine (A), Thymine (T), Cytosine (C), Guanine (G)

What bond connects bases together? Which bases pair together in DNA? How many hydrogen bonds connect each complementary base pairing?

Hydrogen bonds. A pairs with T (2 hydrogen bonds), C pairs with G (3 hydrogen bonds)

Which bases are purines and which are pyrimidines?

Purines: A and G; Pyrimidines: C and T

What is the name given to the shape of the DNA molecule?

Double helix

What is the reason for DNA strands running antiparallel to each other? In which direction does each strand of DNA run?

To allow proper base pairing; One strand runs 5' → 3', the other runs 3' → 5'

What bond forms the sugar-phosphate backbone of DNA?

Phosphodiester bond

Know how to label a DNA molecule.

Refer to slide: label sugar, phosphate, nitrogen bases, hydrogen bonds, directions

Know how to write the complementary DNA sequence when given a strand.

Match A with T and C with G in opposite direction

Why is cell division so important?

Cell division is important for growth, repair, and reproduction

What areas of the body does cell division occur more often and why?

Skin, digestive tract, hair — due to high cell turnover

What is asexual reproduction?

Asexual reproduction is reproduction that requires only one parent and produces genetically identical offspring

What are 3 parts of the cell cycle? Be familiar with the key features of each stage of the cell cycle and know how to label each part.

Interphase: cell grows, performs normal functions, and duplicates its DNA; Mitosis: nucleus divides; Cytokinesis: cytoplasm divides into two cells

What is cloning? How did Dolly the sheep come about? How are plants cloned? How does cloning raise ethical concerns?

Cloning is making a genetically identical organism from a single parent; Dolly the sheep was cloned by transferring the nucleus of an adult cell into an empty egg; Plants are cloned by cuttings or tissue culture; Ethical concerns: identity, individuality, animal welfare, designer cloning

What is sexual reproduction? What 2 main processes does it involve?

Sexual reproduction involves two parents and produces genetically different offspring; Processes: meiosis and fertilization

What are the key differences between mitosis and meiosis?

Mitosis: 1 division → 2 identical diploid cells; Meiosis: 2 divisions → 4 unique haploid gametes

What is the difference between diploid and haploid?

Diploid (2n): 2 sets of chromosomes = 46; Haploid (n): 1 set of chromosomes = 23