Grade 11 Biology Unit 2 - Genetics (unfinished

DNA, Reproduction

What are the three types of inherited characteristics?

Traits, genes, and alleles.

What is a trait?

An expressed characteristic of an organism. Ex. eye colour, hair colour.

What are genes?

Sections of DNA containing instructions for building proteins.

What are alleles?

Versions of genes. Ex. brown eyes or blue eyes.

What does DNA stand for?

Deoxyribonucleic Acid.

What is a monomer of DNA, a polymer, called?

A nucleotide.

What are nucleotides made up of?

1. Nitrogen base (A, T, C, or G)

2. Deoxyribose sugar

3. Phosphate group

How many chromosomes do humans have (typically)?

46

What is the shape of DNA?

Double helix, meaning two strands that spiral together (anti-paralell/opposite directions)

Which parts of the nucleotides form the “backbone” of a DNA strand?

The phosphate group and deoxyribose sugar.

What material forms the “ladder rungs” of a DNA strand?

N bases.

Explain Chargaff’s rule.

N bases are found in predictable ratios -- A bonds with T, and C bonds with G.

What makes up a base pair?

A pair of N bases (A and T or C and G) are bonded with Hydrogen.

What are the names of each Nitrogenous base?

Ademine, Cytosine, Thymine, Guanine.

What is a purine?

A type of molecule with 6- and 5-membered rings in their structure. Each has 2 rings.

What is a pyrimidine?

A type of molecule with 6-membered rings in their structure. Each has 1 ring.

Which two N bases are purines?

Adenine and guanine.

Which two N bases are pyrimidines?

Cytosine and thymine.

If a DNA strand reads ACGTTGAC, what are the corresponding base pairs in order?

TGCAACTG.

If a DNA strand reads GTGACCA, what is the complimentary sequence?

CACTGGT.

Why does mitosis happen?

1. Growth and reproduction

2. Repair and replacement

3. Communication and transport throughout the cell

Bonus - bigger surface area

What are the stages and substages of the cell cycle?

Interphase (Growth phase 1 - normal cell activities, DNA synthesis - chromatin duplication; Growth phase 2 - preparation for mitosis, duplication of organelles), Mitosis (Prophase, Metaphase, Anaphase, Telophase), Cytokinesis (division of cytoplasm/organelles).

What happens in mitosis Prophase?

Chromatin condenses into chromosomes, the nuclear membrane disappears, centrioles move to opposite poles of the cell, and spindle fibers begin to form from the centrioles.

What happens in mitosis Metaphase?

Spindle fibers attatch to chromosomes by their centromere, chromosomes line up along the cell’s equator.

What happens in mitosis Anaphase?

Chromosomes are pulled apart, spindle fibers shorten towards poles, sister chromatids have been separated.

What happens in mitosis Telophase?

Cell begins to divide into two, nuclear membranes reform, chromosomes return to chromatin.

What is asexual reproduction?

Mitosis, 2 identical daughter cells from one parent cell.

What are the advantages/disadvantages of asexual reproduction?

Advantages - no mate is required, save time and energy of mating behaviours, no need for specialized anatomy (reproductive organs), rapid reproduction (fast as 20 minutes).

Disadvantages - if environment changes, genetically identical individuals may not survive.

What is sexual reproduction?

Meiosis produces gametes (sperm/eggs - haploid cells), produces 4 genetically unique cells from 1 parent cell.

What are advantages/disadvantages of sexual reproduction?

Advantages - genetic biodiversity, adaptability and suvival in constantly changing conditions, few surviving individuals can ensure species survival.

Disadvantages - specialized organs, mating behaviours take time/energy, sec is biologically costly and risky.

What is meiosis?

Sexual reproduction, produces 4 genetically unique cells (called gametes, half normal chromosome # - gametes have 23, somatic cells have 46)

What does it mean to be diploid?

Regular chromosome #, ‘2n’, somatic cell number, in humans 2n=46

What does it mean to be haploid?

Half the regular chromosome #, ‘n’, gamete cell number, in humans n=23.

How does meiosis work in males?

Spermatogenesis - 4 sperm produced; each has haploid nucleus, high mitochondria, flagellum (movement); production from puberty to death

How does meiosis work in females?

Oogenesis - 4 cells produced (1 ovum/viable egg, 3 pol