Biology 203 Unit 3: Study Guide

Question

1. Describe the difference between a haploid and a diploid cell.
2. Define asexual reproduction. Give an example of it.
3. Define sexual reproduction. Give an example of it.
4. How is sexual reproduction and asexual reproduction similar? How are they different?

Answer 1

Here is my explanation of your questions, most of the questions were asking for definition and explanation of key vocabulary terms. If you need further explanation or clarification please contact me.

Describe the difference between a haploid and a diploid cell.

By definition, haploid cells have only half the number of chromosomes found in the parent cell.

Haploid cells are sex cell or gametes (sperm and egg). Sex cells are made through meiosis. It is important for sex cells to be haploid because when they fuse together half of the set of chromosomes comes from the mother and half comes from the father. For example, in humans haploid cells have 23 chromosomes. During fertilization, a sperm cell with 23 chromosomes fuses with egg cell with 23 chromosomes the result is a zygote with 46 chromosomes.

In contrast by definition, diploid cells have a full set of chromosomes. Somatic cells, body cells that aren't sex cells, are diploid. Diploid cells are produced through the process of mitosis to help with growth and repair. By having a full set of chromosomes, the somatic cells can divide and pass on all the important genetic information to their daughter cells.

Lastly, I tell my students to remember the difference between haploids and diploids this way- haploid kind of sounds like "half"- so you can remember they have half the number of chromosomes as a "regular" cell. In contrast, "double" and "diploid" both start with the letter "d" so you can remember that they have double copies of each chromosome.

Define asexual reproduction. Give an example of it.

Asexual reproduction is a type of reproduction where offspring come from one parent rather than two. Here are some characteristics of resulting offspring are genetically identical to the parent, sometimes they are referred to as "clones". Some examples of asexual reproduction include 1. mitosis where body cells divide to make more cells for growth and repair of organism, 2. binary fission the process in which prokaryotes duplicate their DNA internally and then split into two identical cells, and 3. budding process in which some yeast and viruses actually grow on an existing one- doesn't involve splitting cell.

Define sexual reproduction. Give an example of it.

Sexual reproduction is a type of reproduction where offspring come from the joining of sex cells from two parents. The resulting offspring are genetically different from each of their parents. Internal fertilization is an example of sexual reproduction- this occurs when fertilization occurs while the egg is still inside the female- this is how humans reproduce.

How is sexual reproduction and asexual reproduction similar? How are they different?

Sexual and asexual reproduction are similar in that they are both used to pass on genetic information to offspring and both processes allow species to survival (by producing more). They are different in the following ways- this list is not exhaustive

1. Number of parents involved: asexual= 1 parent; sexual= 2 parents
2. Types of cells produced: asexual= clones; sexual= gametes
3. Types of genes passed on: asexual= exact copies of parent genes; sexual= recombination of parent genes
4. Amount of energy required and time to develop: asexual= quick process; lots of offspring; not a lot of energy required sexual= slower process; fewer offspring; takes time for offspring to develop
5. Genetic variability: asexual= very little genetic variability; sexual= lots of genetic variability

I hope this helps!

Carly