Bio Exam chapter 11

Average body contains

nearly 40 trillion cells

cells can grow

larger up to a certain point, then they need to divide

to stay alive

cell must allow food, oxygen and water to enter through its membrane

to stay alive 2

waste products must leave through the cell membrane

the rate at which substances enter and leave the cell depends on

surface area

as cells get larger the surface area and volume do

not increase at the same rate

Traffic problems

it becomes too hard to move oxygen and nutrients in and wastes out

a cell runs out of DNA if it grows too

large

cell division

the process by which a cell divides into two new daughter cells (binary fission)

before cell division

DNA must be replicated

Step 1 of cell divison

each daughter cell gets one complete copy of genetic info

cell division cotnrols

the surface is to volume ratio

cell division allows

for a more efficient exchange of material between the cell and its environment

all living things must be

able to reproduce

Asexual Reproduction

production of genetically identical offspring from a single parent

Many single celled organisms (like bacteria)

simply divide

In asex repro ex

some multicellular organisms such as hydra/potatoes

asex repro

allows population to increase rapidly

in asex repro

all offspring are genetically identical

because of asex repro

there is a lack of genetic diversity- less adaptable in changing environments

Sexual reproduction

involves the fusion of 2 reproductive cells formed by 2 parents

sex repro takes place in

most animals and plans, many single celled organisms

in sex repro

offspring inherit genetic info from each parent

sex repro

produces genetic diversity- more adaptable in changing environments

How does ur body heal cuts or broken bones? How do skin cells renew themselves?

Mitosis

cells must make a copy of

their genetic material before cell division

Bacteria DNA is

1000 times longer than the cell itself

cells contain a lot of

DNA

Chromosomes

a bundle of genetic info

Prokaryotic Cells

do not have a nucleus- membrane bound

In P Cells DNA is found in the

cytoplasm

Eukaryotic Cells

contain multiple chromosomes- humans have 46 chromos

In E cells

DNA is tightly bound to proteins called Histones

Chromatin

DNA + Histones. Tightly coils are upon histones and then super coils

Chromosomes are precisely

sep. into 2 daughter cells during cell division

What happens during the cell cycle?

The cell grows, prepares for division, and splits into 2 daughter cells.

What do the daughter cells do after division in the cell cycle?

Each daughter cell goes to another cell cycle.

How quickly can the prokaryotic cell cycle take place?

Very rapidly

What happens to prokaryotic cells during the cell cycle?

Cells grow to a certain size

What process occurs after a prokaryotic cell grows?

Replicates DNA

How do prokaryotic cells divide?

Divides through binary fission

What is the result of the prokaryotic cell cycle?

Two genetically identical daughter cells

What are the four stages of the eukaryotic cell cycle

G1, S, G2, M

G1- cell growth

cells grow and increase in size and synthesizes new proteins and organelles

S phase- replication

s is for synthesis, chromosomes are replicated, results in 2 copies of DNA

G2 phase- prep for cell division

organelles and molecules needed for cell division are reproduced

M phase - cell division

produce 2 daughter cells, M=mitosis

Mitosis

division of the nucleus

Cytokinesis

division of the cytoplasm and completes cell division

Mitosis phases

prophase, metaphase, anaphase, telophase

Mitosis may last from

a few minutes to several days

Prophase

1) 1st and largest phase of mitosis

2) the genetic material inside nucleus condenses

3) chromosomes become visible

Each chromosome has

2 sis chromatids held together by a centromere

centromere

control pt

centrioles

extend spindle fibers

Last step of prophase

moving out to dif parts of cell8

What is the second phase of mitosis?

Metaphase

Which phase of mitosis is the shortest?

Metaphase

During metaphase, where are the centromeres of chromosomes located?

At the metaphase plate

What connects the centromeres of each chromosome to the poles of the spindle during metaphase?

Spindle fibers

Anaphase

3rd phase, sister chromatids sep and move apart, sister chromatids move to opp sides of cell

Telophase

final phase of mitosis, chromosomes begin to decondense, nuclear envelope reforms around chromosome