Cells and tissues Anas Power point

Question 1

Cell theory

Answer 1

basic structural and functional unit of living organisms collective activness of cells subcellular structures – function of cells Cells arise from pre-existing cells

Question 2

Chemical Components of Cells

Answer 2

Carbon Hydrogen Oxygen Nitrogen

Question 3

Anatomy of the Cell

Answer 3

three main regions Nucleus Cytoplasm Plasma membrane

Question 4

The Nucleus

Answer 4

Control center of the cell Contains genetic material (DNA) Three regions Nuclear envelope (membrane) Nucleolus Chromatin

Question 5

The Plasma Membrane

Answer 5

Double phospholipid layer Hydrophilic heads Hydrophobic tails Also contains proteins, cholesterol, and glycoproteins

Question 6

Membrane junctions

Answer 6

Tight junctions (impermeable) Bind cells together into leakproof sheets Desmosomes Anchoring junctions Gap junctions Allow communication

Question 7

Cytoplasm

Answer 7

Site of most cellular activities Major elements: Cytosol Fluid that suspends other elements Organelles Metabolic machinery of the cell Inclusions Chemical substances (stored nutrients, cell products,etc.)

Question 8

Cytoplasmic Organelles

Answer 8

Mitochondria

Carry out reactions where oxygen is used to break down food

Provides ATP for cellular energy

Ribosomes

Protein + ribosomal RNA

Sites of protein synthesis

a)Part of the rough endoplasmic

reticulum

a)Free in the cytoplasm

Question 9

Transport how this process works

Answer 9

1 As the protein is synthesized on the

ribosome, it migrates into the rough ER

cistern.

2 In the cistern, the protein folds into its

functional shape. Short sugar chains

may be attached to the protein (forming

a glycoprotein).

3 The protein is packaged in a tiny

membranous sac called a transport

vesicle.

4 The transport vesicle buds from the

rough ER and travels to the Golgi

apparatus for further processing.

Question 10

Cytoplasmic Organelles

Answer 10

Modifies and packages proteins as:

Cell membrane components

Secretory vesicles

Lysosomes

Question 11

Cytoplasmic Organelles

Answer 11

Lysosomes

Contain enzymes produced by ribosomes

Packaged by the Golgi apparatus

Digest worn-out or nonusable materials within the cell

Question 12

Cytoplasmic Organelles

Answer 12

Peroxisomes

Membranous sacs of oxidase enzymes

Detoxify harmful substances

Break down free radicals

Replicate by pinching in half

Question 13

Cytoplasmic Organelles

Answer 13

Cytoskeleton

internal protein framework of the cell

Three different types of elements

Microfilaments (largest)

Intermediate filaments

Microtubules (smallest)

Question 14

Cytoplasmic Organelles

Answer 14

Centrioles

Rod-shaped bodies made of microtubules

Direct the formation of mitotic spindle during cell division

Question 15

Cellular Projections

Answer 15

Cilia move materials across the cell surface (respiratory system)

Flagella - propel the cell (sperm)

Microvilli - Increase surface area for absorption

Question 16

Cell diversity

Answer 16

Cell’s shape reflects its function

Cells that connect body parts

Fibroblast, erythrocyte

Cell that covers and lines body organs

Epithelial cell

Cells that move organs and body parts

Muscle cells

Cell that stores nutrients

Fat cell

Cell that fight disease

Macrophage

Cell that gathers information and control cells

Nerve cell

Question 17

Cell diversity

Answer 17

. Cells of reproduction

Oocyte

Sperm

Question 18

Solutions and Transport

Answer 18

Solution—homogeneous mixture of two or more components

Solvent—dissolving medium;

Solutes—components in smaller quantities within a solution

Intracellular fluid —nucleoplasm and cytosol

Interstitial fluid —fluid on the exterior of the cell

Selective permeability – barrier (plasma membrane) selects substances to pass through it

Question 19

MEMBRANE TRANSPORT

Answer 19

PASSIVE

No energy is required

DIFFUSION

FILTRATION

ACTIVE Cell provides the metabolic energy (ATP)

Question 20

Passive Processes

Answer 20

Diffusion

Movement is from high concentration to low concentration, or down a concentration gradient

Question 21

Types of diffusion

Answer 21

Types of diffusion

Simple diffusion

lipid-soluble or small molecules

through membrane pores

Facilitated diffusion

lipid-insoluble and large

substances that require

a protein carrier or a channel

Osmosis

Diffusion of water through

aquaporins

Question 22

•Filtration

Answer 22

Water and solutes are forced through a membrane by fluid, or hydrostatic pressure

Question 24

Active Processes

Answer 24

Substances unabled to pass by diffusion

ATP is used for transport

ACTIVE TRANSPORT

ATP energizes protein carriers

substances are moved against concentration gradients

VESICULAR TRANSPORT

Exocytosis

Endocytosis

Phagocytosis – “cell eating”

Pinocytosis – “cell drinking

Question 25

Cell Life Cycle

Answer 25

Cells have two major periods

Interphase

Cell grows

metabolic phase

Cell division

Cell replicates itself

Question 26

DNA Replication

Answer 26

Always precedes cell division

Genetic material is duplicated

DNA uncoils and each side serves

as a template

Question 27

Events of Cell Division

Answer 27

Mitosis—division of the nucleus

Results in the formation of two daughter nuclei

Cytokinesis—division of the cytoplasm

Begins when mitosis is near completion

Results in the formation of two daughter cells

http://www.ck12.org/life-science/Cell-Cycle-in-Life-Science/lecture/Cell-Division-and-the-Cell-Cycle/

Question 28

Stages of Mitosis

Answer 28

Interphase

Cell performs normal functions, Cell growth (G1 and g2), Synthesizes new molecules and organelles

Prophase

Changes occur in nucleus and cytoplasm, chromatin fibers become more tightly coiled and folded, Nucleoli disappear, each duplicated chromosome appears as two identical sister chromatids, mitotic spindle begins to form.

Prometaphase

Nuclear envelope disappears,, each sister chromatid has a protein structure called the kinetochore, some microtubules attach to kinetochores

Metaphase

Mitotic Spindle is fully formed, poles at opposite end of cell, chromosomes convene on metaphase plate, centrometres are lined up on the metaphase plate, for each chromosome the kinetochores of sister chromatids face opposite poles.

Anaphase

Two centrometres of each chromosome come apart separating sister chromatids, each sister chromatid (once separated) becomes a full fledged daughter chromosome. Daughter chromosomes are walked to opposite poles of cell.

Telophase

“Reverse of Prophase”, cell elongation (anaphase) continues, chromatin fiber of each chromosome uncoils and nucleoli reappear, at the end of this phase the mitotic spindle reappears

Cytokinesis

The final stage of the cell cycle, in which the cell’s cytoplasm divides, distributing the organelles into each of the two new cells. Involves a cleavage furrow which pinches the cell in two.

Question 29

Protein Synthesis

Answer 29

• Gene—DNA segment that carries a blueprint for building one protein
• Proteins have many functions

▫Building materials for cells

▫Act as enzymes (biological catalysts)

•RNA is essential for protein synthesis

Question 30

Role of RNA

Answer 30

Messenger RNA (mRNA)

Carries the instructions for building a protein from the nucleus to the ribosome

Transfer RNA (tRNA)

Transfers appropriate amino acids to the ribosome for building the protein

Ribosomal RNA (rRNA)

Helps form the ribosomes where proteins are built

Question 31

Transcription and Translation

Answer 31

Transcription – in the nucleus

Transfer of information from DNA to mRNA

Three-base sequences on mRNA are called codons

Translation – in the cytoplasm

Base sequence of nucleic acid is translated to an amino acid sequence - building blocks of proteins

Question 32

Body Tissues