Grade 11 Biology Unit 2 - Genetic Processes

What is the meaning of DNA?

deoxyribonucleic acid

What are nucleotides?

They are individual units of each strand of DNA.

What are nucleotides composed of?

They are made of a phosphate group, a sugar group, and a Nitrogen containing base.

What are the four different bases in DNA?

adenine (A), thymine (T), cytosine (C), and guanine (G).

In Chargaff’s Rule, what does “Apples in the Trees” mean in nitrogenous bases and pairing?

It means adenine (A) always pair up with thymine (T).

In Chargaff’s Rule, what does “Cars in the Garage” mean in nitrogenous bases and pairing?

It means cytosine (C) always pair up with guanine (G).

What happens if DNA is replicated during Interphase?

When DNA is replicated during Interphase, the double helix unwinds and each strand of DNA serves as a template for a new strand.

What is this term called when DNA is copied, each of the new double-stranded DNA molecules contains one original strand of DNA and one new strand of DNA.

This is called semi-conservative.

What is a Karyotype?

A photograph of pairs of homologous chromosomes in a cell.

How many pairs of chromosomes does humans have?

23 pairs of chromosomes

What are ways to identify chromosomes?

size, banding pattern, and centromere position.

What kind of chromosomes do most pairs have in humans?

Autosomes

22 pairs of chromosomes are in humans, but what is the last pair of chromosomes called?

The last pair are sex chromosomes which determines the biological sex of an organism

What is this genetic disorder called when a pair of chromosomes has an extra copy of ONE more chromosome?

Trisomy

What are homologous chromosomes?

They are chromosomes that contain the same sequences of gene as another chromosome and they are mostly found during Meiosis.

What are diploids?

Cells that contain pairs of homologous chromosomes.

What are haploids?

Cells that contains HALF the number of chromosomes in a parent cells.

What is the purpose of meiosis?

To make haploid gametes for sexual reproduction.

How many chromosomes are in a human somatic cell chromosome?

46 chromosomes

How many chromosomes are in a gamete cell of chromosome?

23 chromosomes

Spermatogenesis

Applying meiosis in males, starts as diploid cells in testes and results in 4 haploid germ cells.

Oogenesis

Applying meiosis in females, starts as diploid germ cells in ovaries and results in 4 haploid cells: 1 ovum and 3 polar bodies.

Synapsis

The aligning of homologous chromosomes during prophase I in meiosis I

crossing over

The exchange of chromosomal segments between a pair of homologous chromosomes.

What is the end results of Meiosis I?

It ends with two haploid daughters.

What is the end results of Meiosis II?

It ends with four haploid daughter cells.

Independent assortment

arranged randomly in metaphase I in meiosis I

What is the chromatin’s structure in the cell during Interphase in Mitosis looks like?

It is structurally loose.

When does the chromatin becomes condensed?

It only becomes condensed in X formation during mitosis

What are chromatids?

They are single-stranded chromosomes.

What happens to chromatids after DNA replication?

They become double-stranded and homologous chromosomes.