Ch 7 Cell Structure Flashcards
Protoplasm
All living parts of a cell
-made up of the nucleus and cytoplasm
What parts of an animal cell can be seen under light microscope
Nucleus, cytoplasm, cell membrane
What is an animal cell surrounded by
Cell or plasma membrane
-membrane surround the protoplasm
Vacuoles
Contain fluid called cell sap ( salts, sugar, pigments )
What do green plant cells contain
Chloroplasts - for photosynthesis
What are plant cells enclosed by
A rigid cell wall made of cellulose
-cell membrane is found just inside cell wall
What are phospholipid made of
Phosphate and lipid
What is cell /plasma membrane composed of
Phospholipids (phospholipid bilayer) and proteins
phospholipid structure
Have a water loving phosphate group and a water hating lipid group
-phosphates are on the surface and lipids are in the middle
Proteins in the cell membrane
-completely or partially embedded in the phospholipid bilayer
-some are attached to the bilayer
-some are detachable and move throughout the bilayer
Selectively permeable
Allows some allows some things to passes through but blocks/ prevents other
Functions of membranes
-membranes retain cell contents
-controls what enters and leaves the cell - selectively permeable
-give some support to the cell
-recognise molecules that touch them
Organelles
Structure found inside cells
-cell membrane
-nucleus
-mitochondria
-chloroplast
-ribosomes
-cell wall
-vacuole
Nucleus
Control centre of the cell- controls the activity of the cell and contains DNA
What is a nucleus surrounded by
A double membrane with numerous nuclear pores
What do nucleus contain
Strands of DNA - arranged into chromosomes
Do every organisms have a definite number of chromosomes
Yes eg humans have 46, ferns have more than 1000
What are located on chromosomes
Genes
Chromosomes (when a cell is not dividing)
Chromosomes are long and interwoven - chromatin (in this form)
Nuclear pores
Allow mRNA in and out of the nucleus
Nucleolus
Makes ribosomes and is part of the nucleus that stains darkly
What makes up a nucleus
- Double membrane
- Nuclear pores - control movement of substances into and out of the nucleus
- DNA - Deoxyribonucleic acid
- Chromatin - tangle of DNA in the nucleus
- Chromosomes- individual strands of DNA
- Nucleolus - contains RNA, DNA, Poteins, and makes ribosomes
Cytoplasm
- jelly like liquid in the cell
- small bodies called organelles are suspended in the cytoplasm
Mitochondria
Supply energy to the cell - respiration
-cells with many mitochondria produce lots of energy eg muscle, liver cells
-cells with less/ few mitochondria produce less energy eg fat cells
What surrounds a mitochondria
Double membrane
How is energy released in a mitochondrion
Energy is released on the inner membrane and then more infoldings, the more energy can be produced.
What does each mitochondrion have
A loop of DNA
What happens if a cell rests for too long
Active mitochondria Converts to inactive form (less foldings)
-excercise causes number of infoldings to increase again
Chloroplasts
Green stuff tires in plants in which photosynthesis occurs
What are chloroplasts surrounded by
Double membrane
Chloroplasts contain
Membrane stacks which green pigment chlorophyll
Loop of DNA
Cell wall function
To support and strengthen the cell
Fully permeable - all molecules can pass through cell walls
What are cell walls made of
Cellulose
Vacuoles
Fluid filled space bounded by membrane
-fluid = cell sap = water, food, minerals, pigments
Function of vacuole
-Provide structural support
-storage
-waste disposal
-protection + growth
Vacuoles in plant vs animal cells
P- large permanent
C- small, temporary (if any)
Ribosomes
Function: to make proteins
-tiny, bead-like structures
-made of RNA, protein
-they combine amino acids to form proteins
Animal cells vs plant cells
Animal cells:
- do not have a cell wall
-do not have chloroplast (chlorophyll)
-do not have a large vacuole
Plant cells:
-have a cell wall
- may have chloroplasts/ chlorophyll
- have a large vacuole
Prokaryotic cells
Do not have a nucleus or membrane-enclosed organelles
Eukaryotic cells
Have a nucleus and organelles which are enclosed by membranes
Describe prokaryotic cells
- single called
- have a circular loop of DNA (not surrounded by membrane)
- have small cells
- don’t have membrane enclosed organelles
- include bacteria
Describe eukaryotic cells
- have a nucleus
- may have membrane-enclosed organelles
- have large cells
- includes animals, plants, fungi
- more advanced than prokaryotic cells
