3/26 ATB – 8th Period

• No ATB – Test Corrections

• Start with • You may use your notes to make corrections

on your test

• When there is 10 minutes left in class we will go over the test

3/26 ATB• FIRST NEW ATB!• Review: What is the purpose of cell respiration?• Today:– QUICKLY grade test corrections (5 minutes)– Start new chapter on cell division– Use books to complete page 2 in your packet starting

on page 274 in the book (show me when done)– THEN, complete the book assignment on page 278, #1a

& b, and all of 2– Book assignment due tomorrow

3/5 ATB

• If a cell was going to divide, what are some things it might need to do?

• Today:– Begin cell reproduction– Online cell reproduction assignment

3/6 ATB

• What makes up your chromosomes?• Today:– Go over the online sheet (then turn it in)– Begin discussing cell division and mitosis

3/27 ATB• What prevents cells from growing to the

size of this room?– Surface area to volume ratio– Information efficiency

• Today:– Begin going over the chapter– Book assignment – due tomorrow

– Movie tomorrow!

Chapter 10 – Cell Growth, Division and Replication

Objectives

• Describe the structure of a chromosome.

• Identify the differences in structure between prokaryotic chromosomes and eukaryotic chromosomes.

• Compare the numbers of chromosomes in different species.

• Explain the differences between sex chromosomes and autosomes.

• Distinguish between diploid and haploid cells.

DIRECTIONS: Read pages 274-278 and answer the following questions as you read.

• When a living organism grows, does it cells get larger or does it just produce more cells?– __Produce more cells____

• What do most cells do after they reach a certain point in size? – ____divide_________

• Describe the two main factors that limit cell size.– Information “overload” - not enough DNA to run the cell– Exchanging materials (surface area to volume ratio)– DNA efficiency

• Describe cell division – – Process by which cells divides into two new daughter cells

• When a cell divides, what are the new cells called? – __Daughter cells_______

• What must a cell do to its DNA before cell division occurs? – ____replicate it______

• What is an example of a type of cell that uses asexual reproduction? – ___bacteria / single cells________

• Describe asexual reproduction – – Production of genetically identical offspring from a single parent

• Describe sexual reproduction – – Offspring that inherit genetic material from from each parent

• One advantages of asexual reproduction is that when conditions are right the reproduce very __rapidly_______. However a problem occurs if conditions are unfavorable because there is a lack of ___diversity_____________.

• One problem of sexual reproduction is that organisms must find a ___mate________ and the growth and __development__________ of the offspring requires ____time_________. However an advantage of sexual reproduction is that it provides ___genetic diversity___.

• Please complete the 10.1 Assessment on page 278, #1a & b and 2.

Review: Why is cell size limited?• Cell size is limited by it’s surface area to

volume ratio– Volume increases faster than surface area as

a cell grows• Not enough DNA to code for all of cells

activities• So what does the cell do?– Divide

• What is the problem with increasing cell size?• Volume increases faster than surface area as a

cell grows– PROBLEM:• needed materials can’t

get in fast enough (O2, glucose) and wastes out fast enough (CO2)• Notice SA increased

only 25 times and thevolume increase125 times

• Now…page 3 of the new packet

Cell Reproduction• Cell Division – – Process in which a cell divides into two new daughter

cells• Mitosis – – Process which ONE cell divides into TWO genetically

identical cells– Asexual reproduction

• Meiosis – – Cell division that produces our gametes (sex cells)

• Mitosis• http://www.youtube.com/watch?v=VlN7K1-9

QB0&feature=related

Chromosome # in Mitosis and Meiosis

• Mitosis• Human cells in mitosis

will have how many chromosomes?– 46

• Why?– The cell needs all the

information in the chromosomes to function.

• Meiosis• Human cells that

undergo meiosis will have how many chromosomes?– 23

• Why?– B/c you can only supply ½

of the genetic material to create offspring

Chromosome Structure• Chromosomes – rod-shaped structures made

of DNA and protein.• Histones -– Proteins that DNA wrap around– Aids in the compact structure

of the chromosome

Chromosome Structure

4/2 ATB

• What does the process of mitosis create? (look in you packet)

• Today:– Packets – page 4– Continue discussing prokaryotic / eukaryotic

chromosomes

Chapter 8Parts of a chromosome• Eukaryotic cells:• Chromatids – – ½ a duplicated chromosome– identical to other half – (replicated in the “S phase” for

replication)• Centromere – – Where sister chromatids are joined.

• Genes – – Bands found on the chromosome that code for traits

• Chromatin –– Uncoiled DNA found in nucleus– Seen when cell isn’t dividing

Chapter 8

• Prokaryotic cells:• Contain only 1 circular chromosome

Chapter 8Comparing Cell Division in Prokaryotes and Eukaryotes

•Prokaryotic cells reproduce faster than eukaryotic cells•Less sophisticated, takes less time

Chromosome Numbers• Different species have a characteristic

number of chromosomes in each cell.• More chromosomes do not equal more

sophisticated• Might mean

chromosomes are smaller

Chromosome Type

• Autosomes– Non-sex chromosomes– 22 pairs

• Sex Chromosomes– determine the sex of an organism.– In humans:• X and Y• XX = female• Xy = male

4/3 ATB

• What does a karyotype show?• Today:– Review what we’ve covered so far– Review karyotyping– Karyotyping activity

• Homologous chromosomes– Chromosomes that carry the same genes (NOT the same

traits)– One from male other from female

• Karyotype– Picture of chromosomes

in a normal dividing cell

Review• What are the two factors that limit cell size?• What are autosomes?• How many autosomes do we have?• How many sex chromosomes do we have?• What are the two sex chromosomes in humans?• What makes up chromosomes?• What are homologous chromosome?• What does the process of mitosis create?• What is a karyotype?

Karyotype cont’d• Used primarily to study chromosome problems• Stop cell in metaphase and stain the chromosomes• Match use length and bands (bands can represent 100’s of

genes)• http://learn.genetics.utah.edu/content/begin/traits/karyotype/

Insect Karyotype• Cut out only ONE set of chromosomes at a

time!• Make sure you align them the same as Figure 1

on the front of the packet• Make sure you line the centromere up on the

line• Share the glue!• Make sure to shut the glue and throw away

paper scraps before you go

4/4 ATB

• What are some ways in which the homologous chromosomes can be paired up?

• Today:– Another Review – Continue with your karyotyping activity (last day)

Review• What is a karyotype?• What are some various chromosome

errors that can be seen in an karyotype?• How many autosomes does a human

have? How many sex chromosomes?• T / F – The more chromosomes an

organisms has the more complex it is

Karyotyping Activity

• Finish cutting and lining up the chromosomes• Then start answering the questions on the

back • You will not have time to work on this

tomorrow