YOMEDIA
Lecture Human anatomy and physiology - Chapter 3: Cells (part d)
Chia sẻ: Tttttttt Tttttttt
| Ngày:
| Loại File: PPT
| Số trang:9
34
lượt xem
2
download
Download
Vui lòng tải xuống để xem tài liệu đầy đủ
This chapter provides knowledge of cell cycle. The main contents of this chapter include all of the following: List the phases of the cell cycle and describe the key events of each phase, describe the process of DNA replication.
AMBIENT/
Chủ đề:
Nội dung Text: Lecture Human anatomy and physiology - Chapter 3: Cells (part d)
- PowerPoint® Lecture Slides
prepared by
Janice Meeking,
Mount Royal College
CHAPTER 3
Cells: The
Living Units:
Part D
Copyright © 2010 Pearson Education, Inc.
- Cell Cycle
• Defines changes from formation of the cell
until it reproduces
• Includes:
• Interphase
• Cell division (mitotic phase)
Copyright © 2010 Pearson Education, Inc.
- Interphase
• Period from cell formation to cell division
• Nuclear material called chromatin
• Four subphases:
• G1 (gap 1)—vigorous growth and metabolism
• G0—gap phase in cells that permanently cease
dividing
• S (synthetic)—DNA replication
• G2 (gap 2)—preparation for division
Copyright © 2010 Pearson Education, Inc.
- G1 checkpoint
(restriction point)
S
Growth and DNA
synthesis G2
Growth and final
G1 preparations for
Growth M division
G2 checkpoint
Copyright © 2010 Pearson Education, Inc. Figure 3.31
- Centrosomes
Interphase (each has 2 Plasma
centrioles) membrane
Nucleolus Chromatin
Nuclear
Interphase envelope
Copyright © 2010 Pearson Education, Inc. Figure 3.33
- DNA Replication
• DNA helices begin unwinding from the
nucleosomes
• Helicase untwists the double helix and
exposes complementary chains
• The Y-shaped site of replication is the
replication fork
• Each nucleotide strand serves as a template
for building a new complementary strand
Copyright © 2010 Pearson Education, Inc.
- DNA Replication
• DNA polymerase only works in one direction
• Continuous leading strand is synthesized
• Discontinuous lagging strand is synthesized in
segments
• DNA ligase splices together short segments of
discontinuous strand
Copyright © 2010 Pearson Education, Inc.
- DNA Replication
• End result: two DNA molecules formed from
the original
• This process is called semiconservative
replication
Copyright © 2010 Pearson Education, Inc.
- Old strand acts as a
DNA polymerase template for synthesis
Free nucleotides
Chromosome of new strand
Leading strand
Two new strands (leading and lagging)
synthesized in opposite directions
Old DNA Lagging
Helicase unwinds strand
the double helix and
exposes the bases
Replication
Adenine fork
Thymine
Cytosine
Guanine
DNA polymerase Old (template) strand
Copyright © 2010 Pearson Education, Inc. Figure 3.32
Thêm tài liệu vào bộ sưu tập có sẵn:
Báo xấu
LAVA
ERROR:connection to 10.20.1.98:9315 failed (errno=111, msg=Connection refused)
ERROR:connection to 10.20.1.98:9315 failed (errno=111, msg=Connection refused)
Đang xử lý...
Thêm vào BST
Báo xấu
